Types of sand used in casting
Good casting can be determined by the pattern and the types of molding sand used. One need to understand the types of molding sand used in casting.
In some my previous post, I have enlighten different articles on casting. Check:
- Different types of Casting tools and equipment
- Types of foundry patterns (casting patterns)
- Different Types of Casting Defects and Remedies
- Difference between Forging and Casting
Today I will be discussing on different types of sand used in casting. The following explained below are molding sand used for casting:
Green sand: this types molding sand is a natural sand with enough moisture in it. It contains clay of about 15 to 30%, 8% of water and silica. The clay and water act as binding material that give strength to the mold. it is used only for simple and rough casting. It is used for both ferrous and non-ferrous metal.
Dry sand: this casting sand is obtained when the moisture from green sand is removed. It used for large and heavy casting, because the molding sand offers greater strength, rigidity and thermal stability to the casting.
Facing sand: as the name implies, facing sand is used for facing the mold. it consists of fresh silica sand and clay. That is, no used sand is added. It is used directly next to the surface of the pattern. Facing casting sand must have high refractoriness and strength because it comes in direct contact with the hot molten metal. This molding sand offers the mold a very fine grain.
Core sand: this is another types of molding sand contains silica sand mixed with core oil (linseed oil, resin, and mineral oil) and other binding materials like, dextrin, corn floor, and sodium silicate. It is used for cores making and has high compressive strength.
Loam sand: loam sand is equal mixture of sand and clay with a sufficient amount of water added to it. It is also used for large and heavy mold like, hoppers, turbine parts etc.
Parting sand: this molding is pure silica sand poured on the faces of pattern before molding. Parting sand is sprinkled on the pattern before it is embedded in the molding sand. This casting sand is also sprinkled on the contact surface of cope, drag and cheek.
Backing and floor sand: this casting sand is used to back up the facing sand and to fill the volume of the box. It is also known as floor sand.
System sand: this molding sand is applicable to mechanical heavy castings. It has high strength, permeability and refractoriness. System sand is used for machine molding to fill the whole flask. Facing sand is not use in this molding because cleaned and has special additives.
Molasses sand: this molding sand is also used for core making and small casting of intricate shapes. It contains molasses as it source of binding.
And that is it for this article, types of molding sand (casting sand). I will hopefully believe you understand this article by answering the question below via our comment box. Don’t forget to share with other student. Thanks for reading!
Question: briefly explain loam sand