ANS:B - cast

Certainly! "Cast" in the context of metallurgy refers to a type of metal that has been melted and poured into a mold to solidify into a desired shape. This process is known as casting. Here's an explanation of the casting process and its characteristics:

1. Casting Process: Casting involves several steps:
   • Pattern Making: A pattern, typically made of wood, plastic, or metal, is created based on the desired shape of the final product.
   • Mold Preparation: The pattern is placed in a mold, and molding material (such as sand or metal) is packed around it to create a cavity called the mold.
   • Melting: The metal to be cast is melted in a furnace, such as a cupola, electric arc furnace, or induction furnace.
   • Pouring: Once molten, the metal is poured into the mold cavity through a gating system.
   • Solidification: The metal cools and solidifies inside the mold, taking the shape of the cavity.
   • Removal: After solidification, the casting is removed from the mold, cleaned, and finished as necessary.
2. Types of Casting: There are various methods of casting, including:
   • Sand Casting: The most common method, where sand is used as the mold material. Sand casting is versatile and suitable for both small and large parts.
   • Investment Casting: Also known as lost-wax casting, this method uses a wax pattern that is melted away during the casting process.
   • Die Casting: A process where molten metal is forced into a steel mold cavity under high pressure. Die casting is used for high-volume production of small to medium-sized parts with complex shapes.
   • Continuous Casting: Used for producing long, continuous metal shapes, such as billets, bars, and tubes.
3. Characteristics of Cast Metal:
   • Versatility: Casting can produce parts with complex shapes and intricate details.
   • Material Choice: A wide range of metals and alloys can be cast, including iron, steel, aluminum, brass, and copper.
   • Surface Finish: Castings typically have a rough surface finish due to the texture of the mold material. Additional finishing processes may be required to achieve the desired surface quality.
   • Porosity: Castings may contain internal voids or porosity due to gas entrapment during solidification. Proper gating and venting systems help minimize porosity.