Which process involves passing a piece of metal between two rolls to reduce thickness?

• A. Rolling
• B. Forging
• C. Casting
• D. Extrusion

Answer: (A)

Rolling is the process described: a piece of metal is passed between two rotating rolls, and as it is squeezed, its thickness is reduced. The metal deforms plastically under the compressive force from the rolls, and because volume is roughly conserved, the length increases as the thickness decreases. This reduction can occur in one or more passes, with the roll gap adjusted to reach the desired thickness. The metal can be hot-rolled (above recrystallization temperature) for easier deformation and different properties, or cold-rolled at room temperature for better surface finish and strength.

The other options don’t fit this description because forging uses dies to shape material with localized compression, casting involves pouring liquid metal into a mold, and extrusion pushes metal through a die to create a desired cross-section.