green sand and dry sand

molding sand: constituents, types and properties

molding sand: constituents, types and properties

The general sources of receiving molding sands are the sea shores, rivers, lakes, deserts and granular elements of rocks. Molding sands can be classified mainly into two types namely natural or synthetic. Natural molding sands contains sufficient amount of binder material. Whereas synthetic molding sands are prepared artificially using basic sand molding constituents (silica sand in 85-91%, binder 6-11%, water or moisture content 2-8%) and other additives in proper proportion by weight with perfect mixing and mulling in suitable equipments.

Silica sand in form of granular quarts is the main constituent of molding sand having enough refractoriness which can impart strength, stability and permeability to molding and core sand. But along with silica small amounts of iron oxide, alumina, lime stone (CaCO3), magnesia, soda and potash are present as impurities. The chemical composition of silica sand gives an idea of the impurities like lime, magnesia, alkalis etc. present. The presence of excessive amounts of iron oxide, alkali oxides and lime can lower the fusion point to a considerable extent which is undesirable. The silica sand can be specified according to the sand grain size and the shape (angular, sub-angular and rounded) of the sand.

Binders can be either inorganic or organic substance. Binders included in the inorganic group are clay sodium silicate and port land cement etc. In foundry shop, the clay acts as binder which may be Kaolinite, Ball Clay, Fire Clay, Limonite, Fullers earth and Bentonite. Binders included in the organic group are dextrin, molasses, cereal binders, linseed oil and resins like phenol formaldehyde, urea formaldehyde etc. Binders of organic group are mostly used for core making. Among all the above binders, the bentonite variety of clay is the most commonly used. However, this clay alone cant develop bonds among sand grins without the presence of moisture content in molding sand and core sand.

The amount of moisture content in the molding sand varies from 2 to 8%. This amount is added to the mixture of clay and silica sand for developing bonds. This is the amount of water required to fill the pores between the particles of clay without separating them. This amount of water is held rigidly by the clay and is mainly responsible for developing the strength in the sand. The effect of clay and water decreases permeability with increasing clay and moisture content. The green compressive strength first increases with the increase in clay content, but after a certain value, it starts decreasing. For increasing the molding sand characteristics some other additional materials besides basic constituents are added which are known as additives.

Additives are the materials generally added to the molding and core sand mixture to develop some special property in the sand. Some commonly used additives for enhancing the properties of molding and core sands are coal dust, corn flour, dextrin, sea coal, pitch, wood flour, silica flour.

Coal dust is added mainly for producing a reducing atmosphere during casting process. This reducing atmosphere results in any oxygen in the poles becoming chemically bound so that it cannot oxidize the metal. It is usually added in the molding sands for making molds for production of grey iron and malleable cast iron castings.

Corn flour belongs to the starch family of carbohydrates and is used to increase the collapsibility of the molding and core sand. It is completely volatilized by heat in the sand mould, thereby leaving space between the sand grains. This allows free movement of sand grains, which finally gives rise to mould wall movement and decreases the mold expansion and hence defects in castings. Corn sand if added to molding sand and core sand improves significantly strength of the mold and core.

Sea coal is the fine powdered bituminous coal which positions its place among the pores of the silica sand grains in molding sand and core sand. When heated, sea coal changes to coke which fills the pores and is unaffected by water. Because to this, the sand grains become restricted and cannot move into a dense packing pattern. Thus, sea coal reduces the mould wall movement and the permeability in mold and core sand and hence makes the mold and core surface clean and smooth.

Pitch is distilled form of soft coal. It can be added from 0.02 % to 2% in mold and core sand. Pitch enhances hot strengths, surface finish on mold surfaces and behaves exactly in a manner similar to that of sea coal.

Wood flour is a fibrous material mixed with a granular material like sand. Wood flour is relatively long thin fibers prevent the sand grains from making contact with one another. wood flour can be added in between 0.05 % to 2% in mold and core sand. Wood flour volatilizes when heated, thus allowing the sand grains room to expand. Wood flour will increase mould wall movement and decrease expansion defects. Wood flour also increases collapsibility of both mold and core.

Silica flour is called as pulverized silica. Pulverized silica can be easily added up to 3% which increases the hot strength and finish on the surfaces of the molds and cores. It also reduces metal penetration in the walls of the molds and cores.

Backing sand or floor sand is used to back up the facing sand and is used to fill the whole volume of the molding flask. Backing sand is sometimes called black sand because of old, repeatedly used molding sand is black in color due to addition of coal dust and burning on coming in contact with the molten metal.

Core sand is used for making cores and it is sometimes also known as oil sand. Core sand is highly rich silica sand mixed with oil binders such as core oil which composed of linseed oil, resin, light mineral oil and other bind materials. Pitch or flours and water may also be used in large cores for the sake of economy.

Green sand that has been dried or baked in suitable oven after the making mold and cores is called dry sand. It possesses more strength, rigidity and thermal stability. Dry sand is mainly used for larger castings. Mold prepared in this sand are known as dry sand molds.

Facing sand forms the face of the mould. It is next to the surface of the pattern and it comes into contact with molten metal when the mould is poured. Initial coating around the pattern and hence for mold surface is given by facing sand. Facing sand have high strength refractoriness. Facing sand is made of silica sand and clay, without the use of already used sand. Different forms of carbon are used in facing sand to prevent the metal burning into the sand. A facing sand mixture for green sand of cast iron may consist of 25% fresh and specially prepared and 5% sea coal. They are sometimes mixed with 6-15 times as much fine molding sand to make facings. The layer of facing sand in a mold usually ranges between 20-30 mm. From 10 to 15% of the whole amount of molding sand is the facing sand.

Green sand is also known as tempered or natural sand which is a just prepared mixture of silica sand with 18 to 30% clay, having moisture content from 6 to 8%. The clay and water furnish the bond for green sand. It is fine, soft, light, and porous. Green sand is damp, when squeezed in the hand and it retains the shape and the impression to give to it under pressure. Molds prepared by this sand are not requiring backing and hence are known as green sand molds. Green sand is easily available and it possesses low cost. Green sand is commonly employed for production of ferrous and non-ferrous castings.

Loam sand is mixture of sand and clay with water to a thin plastic paste. Loam sand possesses high clay as much as 30-50% and 18% of water. Patterns are not used for loam molding and shape is given to mold by sweeps. Loam sand is particularly employed for loam molding used for large grey iron castings.

Parting sand without binder and moisture is used to keep the green sand not to stick to the pattern and also to allow the sand to the parting surface the cope and drag to separate without clinging. Parting sand is clean clay-free silica sand which serves the same purpose as parting dust.

In mechanized foundries where machine molding is employed. System sand is used to fill the whole molding flask. In mechanical sand preparation and handling units, facing sand is not used. The used sand is cleaned and re-activated by the addition of water and special additives. This is known as system sand. Since the whole mold is made of this system sand, the properties such as strength, permeability and refractoriness of the molding sand must be higher than those of backing sand.

Cohesiveness is property of molding sand by virtue which the sand grain particles interact and attract each other within the molding sand. Thus, the binding capability of the molding sand gets enhanced to increase the green, dry and hot strength property of molding and core sand.

After the molten metal in the mould gets solidified, the sand mould must be collapsible so that free contraction of the metal occurs and this would naturally avoid the tearing or cracking of the contracting metal. In absence of collapsibility property the contraction of the metal is hindered by the mold and thus results in tears and cracks in the casting. This property is highly required in cores.

As soon as the molten metal is poured into the mould, the moisture in the sand layer adjacent to the hot metal gets evaporated and this dry sand layer must have sufficient strength to its shape in order to avoid erosion of mould wall during the flow of molten metal. The dry strength also prevents the enlargement of mould cavity cause by the metallostatic pressure of the liquid metal.

Flowability or plasticity is the ability of the sand to get compacted and behave like a fluid. It will flow uniformly to all portions of pattern when rammed and distribute the ramming pressure evenly all around in all directions. Generally sand particles resist moving around corners or projections. In general, flowability increases with decrease in green strength and vice versa. Flowability increases with decrease in grain size of sand. The flowability also varies with moisture and clay content in sand.

The green sand after water has been mixed into it, must have sufficient strength and toughness to permit the making and handling of the mould. For this, the sand grains must be adhesive, i.e. they must be capable of attaching themselves to another body and. therefore, and sand grains having high adhesiveness will cling to the sides of the molding box. Also, the sand grains must have the property known as cohesiveness i.e. ability of the sand grains to stick to one another. By virtue of this property, the pattern can be taken out from the mould without breaking the mould and also erosion of mould wall surfaces does not occur during the flow of molten metal. The green strength also depends upon the grain shape and size, amount and type of clay and the moisture content.

Permeability is also termed as porosity of the molding sand in order to allow the escape of any air, gases or moisture present or generated in the mould when the molten metal is poured into it. All these gaseous generated during pouring and solidification process must escape otherwise the casting becomes defective. Permeability is a function of grain size, grain shape, and moisture and clay contents in the molding sand. The extent of ramming of the sand directly affects the permeability of the mould. Permeability of mold can be further increased by venting using vent rods.

Refractoriness is defined as the ability of molding sand to withstand high temperatures without breaking down or fusing thus facilitating to get sound casting. It is a highly important characteristic of molding sands. Refractoriness can only be increased to a limited extent. Molding sand with poor refractoriness may burn on to the casting surface and no smooth casting surface can be obtained. The degree of refractoriness depends on the SiO2 i.e. quartz content, and the shape and grain size of the particle. The higher the SiO2 content and the rougher the grain volumetric composition the higher is the refractoriness of the molding sand and core sand. Refractoriness is measured by the sinter point of the sand rather than its melting point.

In addition to above requirements, the molding sand should not stick to the casting and should not chemically react with the metal. Molding sand need be economically cheap and easily available in nature. It need be reusable for economic reasons. Its coefficients of thermal expansion need be sufficiently low.

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8 different types of moulding sand with their properties

8 different types of moulding sand with their properties

In this article, you learnwhat is moulding sand, types of moulding sand and their properties.Moulding Sand And TypesContents show1. Moulding Sand And Types2. Types of Moulding Sand2.1. 1. Green Sand2.2. 2. Dry Sand2.3. 3. Loam Sand2.4. 4. Facing Sand2.5. 5. Backing Sand2.6. 6. System Sand2.7. 7. Parting Sand2.8. 8. Core Sand3. Properties of Moulding SandThe Moulding sand is also known as foundries sand, this sand is commonly used for making moulds. Natural sand located on the bed and banks of rivers gives a larger source, although high-quality silica sand is also mined.Image Credit: Indiamart.comThe sand is chemically Si02, silicon dioxide in a granular manner. Ordinary river sand contains a percentage of clay, moisture, non-metallic impurities and traces of magnesium and calcium salts besides silica grains. After appropriate treatment, this sand is used to make a mould.Types of Moulding SandFollowing are the 8 different types of moulding sands:GreensandDry sandLoam sandFacing sandBacking sandSystem sandParting sandCore sand1. Green SandGreen sandis asandorsandstonewhich has a greenish colour. it is a mixture of silica sand with 18 to 30% clay, having total water of 6 to 8%. It is soft, light and porous with clay and water furnishing the bond for green sand.In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The Moulding sand is also known as foundries sand, this sand is commonly used for making moulds. Natural sand located on the bed and banks of rivers gives a larger source, although high-quality silica sand is also mined.Image Credit: Indiamart.comThe sand is chemically Si02, silicon dioxide in a granular manner. Ordinary river sand contains a percentage of clay, moisture, non-metallic impurities and traces of magnesium and calcium salts besides silica grains. After appropriate treatment, this sand is used to make a mould.Types of Moulding SandFollowing are the 8 different types of moulding sands:GreensandDry sandLoam sandFacing sandBacking sandSystem sandParting sandCore sand1. Green SandGreen sandis asandorsandstonewhich has a greenish colour. it is a mixture of silica sand with 18 to 30% clay, having total water of 6 to 8%. It is soft, light and porous with clay and water furnishing the bond for green sand.In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The sand is chemically Si02, silicon dioxide in a granular manner. Ordinary river sand contains a percentage of clay, moisture, non-metallic impurities and traces of magnesium and calcium salts besides silica grains. After appropriate treatment, this sand is used to make a mould.Types of Moulding SandFollowing are the 8 different types of moulding sands:GreensandDry sandLoam sandFacing sandBacking sandSystem sandParting sandCore sand1. Green SandGreen sandis asandorsandstonewhich has a greenish colour. it is a mixture of silica sand with 18 to 30% clay, having total water of 6 to 8%. It is soft, light and porous with clay and water furnishing the bond for green sand.In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Following are the 8 different types of moulding sands:GreensandDry sandLoam sandFacing sandBacking sandSystem sandParting sandCore sand1. Green SandGreen sandis asandorsandstonewhich has a greenish colour. it is a mixture of silica sand with 18 to 30% clay, having total water of 6 to 8%. It is soft, light and porous with clay and water furnishing the bond for green sand.In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Green sandis asandorsandstonewhich has a greenish colour. it is a mixture of silica sand with 18 to 30% clay, having total water of 6 to 8%. It is soft, light and porous with clay and water furnishing the bond for green sand.In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

In green sand, It is slightly wet when squeezed by hand. It has the ability to maintain the shape and impression given to it under the pressure. The green sand can be easily available and it has a low cost. The mould that is prepared in this sand is called green sand mould. It is commonly used for the production of ferrous and non-ferrous castings.Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Read Also:Heat treatment: Types, Working and Process of Heat TreatmentMetal Casting Process: Types, Stages of Metal Casting2. Dry SandThe Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The Green sand that has been dried or backed after the mould is made is called dry sand. They are suitable for large castings. Moulds prepared in dry sand are known as dry sand moulds. If we talk about the physical composition of dry sand, it is similar to green sand except for water.3. Loam SandThe Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The Loam sand with 50% of clay is called loam sand. They are also suitable for large castings. It is a mixture of sand and clay and water is present in such a quantity that it forms a thin plastic paste. In these types of sand, moulding patterns are not used.4. Facing SandIt forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

It forms the face of the mould. The facing sand is used directly next to the patterned surface and comes into direct contact with the molten metal when the molten metal is poured into the mould. It has high strength and refractivity as it comes in contact with molten metal. It is made of clay and silica sand in addition to unused sand.5. Backing SandThe backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The backing sand is also called floor sand used to back up the facing sand. It is an old and frequently used moulding sand is used for backing purpose. It is sometimes called black sand because of the addition of coal dust and burning due to in contact with the molten metal.6. System SandIn mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

In mechanical sand preparation and handling units, facing sand is not encountered. The sand that is used is cleaned and reactivated by adding water, binder and special additives. And the sand we get it is called system sand.The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The system sand is used to fill the entire flask in the mechanical casting where machine moulding is employed. The mould made of this sand has high strength, permeability and refractivity.7. Parting SandThe parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The parting sand is used to avoids sticking of green sand to the pattern. And also it allows in easy removal of cope and drag. This parting serves the same purpose as dust. It is pure clay free silica sand.8. Core SandThe core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

The core sand is the sand for making cores. It is also called oil sand because it is a mixture of silica sand and core oil. Core oil is a mixture of linseed oil, resin, light mineral oil and other binding materials. For the sake of economy, pitch or flour and water can be used to make large cores.[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

[quads id=2]Properties of Moulding SandGood, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Good, well-prepared moulding sand must have the following properties:Refractoriness It should be able to withstand high temperature.Permeability Ability to allow gases, water vapour and air to pass through it.Greensand strength When the mould is formed of moist sand, it must have sufficient strength, otherwise, the mould will break.Good flowability When it is arranged around a pattern in a moulding box, it must be able to fill all nooks and corners, otherwise the impression of pattern in mould would not be sharp and clear.Good collapsibility It should collapse easily after the casting has cooled down and has been extracted after breaking the mould. It is particularly important in case of care making.Cohesiveness Ability of sand grains to stick together. Without cohesiveness, the mould will lack strength.Adhesiveness Ability of the sand to stick to other bodies. if the moulding sand does not stick to the wall of moulding box, the whole mould will slip through the box.Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Thats it, thanks for reading. If you have any question or doubts about Types of Moulding Sand ask in the comment section below. Share this article if it is worth sharing.Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Read Next:What is Cast Iron Its properties, Effects of Impurities and Types of Cast Iron [Explained]Metal Saw Machine and Types of Sawing MachineHeat treatment: Types, Working and Process of Heat Treatment

Saif M. is a Mechanical Engineer by profession. He completed his engineering studies in 2014 and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at www.theengineerspost.com...

the difference between green sand casting process and resin sand casting process

the difference between green sand casting process and resin sand casting process

In the past, one client asked us the difference between green sand casting process and resin sand casting process. Herein, I make a brief introduction to these two casting processes, and hope it could be helpful for other casting purchasers. Green sand casting process is screening and mixing the wet sands, and filling the sands into the sand boxes, then use machines or just by workers to tamp the sands, then pouring the liquid iron into the sand molds. Resin sand casting process is mixing the furan resin and sand together, then filling the mixed sands into the sand boxes, then after tamping, using the paints to flush the surfaces of molds, then burning the paints to make the sand molds to become very hard, finally, pouring the liquid iron into the solid sand molds. 1. Materials The green sand casting process mainly uses the green sands as the molding material. The green sand is a kind of wet sand. The resin sand casting process mainly uses the resin sand as the molding material, and need to use the alcohol paints. Since the furan resin is more expensive, the resin sand castings will be more expensive than green sand castings. 2. Equipments As for the traditional green sand casting process, it only needs sand boxes and workers, so no equipment needed. Today, more and more iron foundries in China use molding machines or automatic molding machines. The resin sand casting process usually needs equipments to mix the resin sand and fill the sands into the sand boxes. 3. Production time The resin sand casting process has an extra time to flush the paints, and burn the paints and wait the resin molds become hard. Therefore, it needs more production time, therefore, more costs.

If the green sand casting process uses the automatic molding machines, it will have very high production rate, one FBO molding line could normally produce 20 tons each day. Therefore, automatic molding line usually produce iron castings for the automotive industrial. 4. Casting quality The casting quality has big difference for these two processes. Since resin sand casting process uses the hard molds, therefore, resin sand castings have better surface smoothness, higher dimensional tolerance, and less surface and inside casting defects, such as sand holes, air holes and shrinkage. 4. Suitable casting products Resin sand casting process is suitable to produce large iron castings with weight range from dozens of kilograms to several tons. Green sand casting process is suitable to produce small and medium castings with weight under 50 kilograms. Interestingly, as for the very large iron castings with weight of several tons, such as the dryer cylinders for the paper manufacturing machinery, the green sand casting process is the suitable choice. However, you can not produce so large castings by sand boxes, but just produce them by digging the large holes under ground. Although there are so many differences between these two casting processes, it is not absolutely to judge your parts have to use certain casting process, the iron foundries should consider the suitable production process according to their technical conditions and capability.

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the advantages and disadvantages of green sand molding, no-bake sand, resin shell molding, lost wax, die casting, lost foam, permanent mold and centrifugal molding

the advantages and disadvantages of green sand molding, no-bake sand, resin shell molding, lost wax, die casting, lost foam, permanent mold and centrifugal molding

Comparing the advantages and disadvantages of various metal casting processes, including green sand molding, no-bake sand molding, resin shell sand molding, lost wax investment casting, die casting, lost foam, permanent mold, and centrifugal molding processes. Green Sand Molding The green sand process utilizes a mold made of compressed or compacted moist sand packed around a wood or metal pattern. A metal frame or flask is placed over the pattern to produce a cavity representing one half of the casting. The sand is compacted by either jolting or squeezing the mold.

The other half of the mold is produced in like manner and the two flasks are positioned together to form the complete mold. If the casting has hollow sections, cores consisting of hardened sand (baked or chemically hardened) are used.

High-Density Molding (High Squeeze Pressure / Impact) Large air cylinders, hydraulics, and innovative explosive methods have improved the sand compaction around the pattern, improving the standards of accuracy and finish which can be achieved with certain types of castings. Advantages Most ferrous / non-ferrous metals can be used. Low Pattern & Material costs. Almost no limit on size, shape or weight of part. Adaptable to large or small quantities Used best for light, bench molding for medium-sized castings or for use with production molding machines. Disadvantages Low design complexity. Lower dimensional accuracy. No-Bake Sand Molding Chemical binders (furan or urethane) are mixed with sand and placed in mold boxes surrounding the pattern halves. At room temperature, the molds become rigid with the help of catalysts. The pattern halves are removed and the mold is assembled with or without cores. Advantages Most ferrous / non-ferrous metals can be used. Adaptable to large or small quantities High strength mold Better as-cast surfaces. Improved dimensional repeatability Less skill and labor required then in conventional sand molding. Better dimensional control. Disadvantages Sand temperatures critical. Patterns require additional maintenance. Resin Shell Sand Molding Resin-bonded silica sand is placed onto a heated pattern, forming shell-like mold halves. Pattern halves are bonded together with or without cores. Probably the earliest, most automated and most rapid of mold (and core making) processes was the heat-curing technique known as the shell process.

Ejector pins enable the mold to be released from the pattern and the entire cycle is completed in seconds depending upon the shell thickness desired. The two halves of the mold, suitably cored, are glued and clamped together prior to the pouring of the metal. Shell molds may be stored for long periods if desired. Because of pattern costs, this method is best suited to higher volume production. Advantages Adaptable to large or medium quantities Most ferrous / non-ferrous metals can be used. Rapid production rate. Good dimensional casting detail and accuracy. Shell molds are lightweight and may be stored almost indefinitely. Disadvantages Since the tooling requires heat to cure the mold, pattern costs and pattern wear can be higher. Energy costs are higher. Material costs are higher than those for green sand molding. Permanent Mold Permanent molds consist of mold cavities machined into metal die blocks and designed for repetitive use. Currently, molds are usually made of cast iron or steel, although graphite, copper and aluminum have been used.

Gravity Permanent Mold -The flow of metal into a permanent mold using gravity only is referred to as a gravity permanent mold. There are two techniques in use: static pouring, where metal is introduced into the top of the mold through downsprues similar to sand casting; and tilt pouring, where metal is poured into a basin while the mold is in a horizontal position and flows into the cavity as the mold is gradually tilted to a vertical position.

Low-Pressure Permanent Mold - Low-pressure permanent mold is a method of producing a casting by using a minimal amount of pressure (usually 5-15 lb/sq in.) to fill the die. It is a casting process that helps to further bridge the gap between sand and pressure die casting. Advantages Superior mechanical properties. Produces dense, uniform castings with high dimensional accuracy. Excellent surface finish and grain structure. The process lends itself very well to the use of expendable cores and makes possible the production of parts that are not suitable for the pressure die casting process. Repeated use of molds. Rapid production rate with low scrap loss. Disadvantages Higher cost of tooling requires a higher volume of castings. The process is generally limited to the production of somewhat small castings of simple exterior design, although complex castings such as aluminum engine blocks and heads are now commonplace. Die Casting This process is used for producing large volumes of zinc, aluminum and magnesium castings of intricate shapes. The essential feature of die-casting is the use of permanent metal dies into which the molten metal is injected under high pressure (normally 5000 psi or more).

The rate of production of die-casting depends largely on the complexity of design, the section thickness of the casting, and the properties of the cast metal. Great care must be taken with the design and gating of the mold to avoid high-pressure porosity to which this process is prone. Advantages Cost of castings is relatively low with high volumes. High degree of design complexity and accuracy. Excellent smooth surface finish. Suitable for relatively low melting point metals (1600F/871C) like lead, zinc, aluminum, magnesium and some copper alloys. High production rates. Disadvantages Limits on the size of castings - most suitable for small castings up to about 75 lb. Equipment and die costs are high. Investment Casting (Lost Wax) Investment Casting is the process of completely investing a three-dimensional pattern in all of its dimensions to produce a one-piece destructible mold into which molten metal will be poured. A refractory slurry flows around the wax pattern, providing excellent detail.

The wax patterns are assembled on a "tree" and invested with a ceramic slurry. The tree is then immersed into a fluidized bed of refractory particles to form the first layer of the ceramic shell. The mold is allowed to dry and the process repeated with coarser material until sufficient thickness has been built up to withstand the impact of hot metal.

When the slurry hardens, the wax pattern is melted out and recovered and the mold or ceramic shell is oven cured prior to casting. Most materials can be cast by this process but the economics indicate that fairly high volume is necessary and the shape and complexity of the castings should be such that savings are made by eliminating machining. Advantages Excellent accuracy and flexibility of design. Useful for casting alloys that are difficult to machine. Exceptionally fine finish. Suitable for large or small quantities of parts. Almost unlimited intricacy. Suitable for most ferrous / non-ferrous metals. No flash to be removed or parting line tolerances. Disadvantages Limitations on size of casting. Higher casting costs make it important to take full advantage of the process to eliminate all machining operations. Expandable Pattern Casting (Lost Foam) Also known as Expanded Polystyrene Molding or Full Mold Process, the EPC or Lost Foam process is an economical method for producing complex, close-tolerance castings using an expandable polystyrene pattern and unbonded sand.

The EPC process involves attaching expandable polystyrene patterns to an expandable polystyrene gating system and applying a refractory coating to the entire assembly. After the coating has dried, the foam pattern assembly is positioned on several inches of loose dry sand in a vented flask. Additional sand is then added while the flask is vibrated until the pattern assembly is completely embedded in sand.

A suitable downsprue is located above the gating system and sand is again added until it is level to the top of the sprue. Molten metal is poured into the sprue, vaporizing the foam polystyrene, perfectly reproducing the pattern. Gases formed from the vaporized pattern permeate through the coating on the pattern, the sand and finally through the flask vents.

In this process, a pattern refers to the expandable polystyrene or foamed polystyrene part that is vaporized by the molten metal. A pattern is required for each casting. Advantages No cores are required. Reduction in capital investment and operating costs. Closer tolerances and walls as thin as 0.120 in. No binders or other additives are required for the sand, which is reusable. Flasks for containing the mold assembly are inexpensive, and shakeout of the castings in unbonded sand is simplified and do not require the heavy shakeout machinery required for other sand casting methods. Need for skilled labor is greatly reduced. Casting cleaning is minimized since there are no parting lines or core fins. Disadvantages The pattern coating process is time-consuming, and pattern handling requires great care. Good process control is required as a scrapped casting means replacement not only of the mold but the pattern as well. Centrifugal Molding The Centrifugal Casting process consists of a metal or graphite mold that is rotated in the horizontal or vertical plane during solidification of the casting. Centrifugal force shapes and feeds the molten metal into the designed crevices and details of the mold. The centrifugal force improves both homogeneity and accuracy of the casting.

This method is ideally suited to the casting of cylindrical shapes, but the outer shape may be modified with the use of special techniques. Advantages Rapid production rate. Suitable for Ferrous / Non-ferrous parts. Good soundness and cleanliness of castings. Ability to produce extremely large cylindrical parts. Disadvantages Limitations on shape of castings. Normally restricted to the production of cylindrical geometric shapes.

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green sand moulding - steps , advantages and disadvantages

green sand moulding - steps , advantages and disadvantages

A green sand mould is composed of a mixture of sand (silica sand SiO2), clay (act as binder), and water. The word green is associated with the condition of wetness or freshness and because the mould is left in the damp condition, hence the name green sand mould. This type of mould is the cheapest and has the advantage that used sand is readily reclaimed. But the mould being in the damp condition, is weak and cannot be stored for a longer period. Hence such moulds are used for small and medium sized casting.

Open-sand Method It is simplest form of green sand moulding, particularly suitable for solid patterns. For convenience in working and pouring, the entire mould is made in the foundry floor or in a bed of sand above floor level. Moulding box is not necessary and the upper surface of the mould is open to air. After proper levelling the pattern is pressed in the sand bed for making mould. Pouring basin is made at one end of the mould, and the overflow channel cut at the exact height from the bottom face of the mould for giving necessary thickness.

Bedded-in method In this method, the pattern is hammered down or pressed to bed it into the sand of the foundry floor or in a drag filled partially with sand to form the mould cavity. The sand should be rammed close to the pattern sand; a cope is placed over the pattern. The cope is rammed up, runners and risers are cut and the cope box is lifted. Now the pattern is withdrawn, the surfaces of drag and cope replaced in its correct position for completing the mould.

iii) Turn-over method One pattern-halfis placed with its flat side on a moulding board, a drag is rammed and rolled over. The other pattern half and a cope box are placed in position. After ramming the cope is lifted off and the two pattern halves shaken and withdrawn. Now the cope is replaced on the drag for assembling the mould.

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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