Which statement best describes hot-working operations?

• A. Large deformations are possible, and the metal remains soft and ductile.
• B. Deformations are always small.
• C. The metal becomes brittle after processing.
• D. It requires cooling to cryogenic temperatures.

Answer: (A)

Hot-working means deforming metal at temperatures above its recrystallization temperature, so the material is in a soft, ductile state. At these high temperatures, dynamic recrystallization can occur as the metal is deformed, relieving strain hardening and allowing large plastic strains in a single operation. That’s why large deformations are possible and the metal remains workable rather than hard and brittle. The idea that deformations must be small, that the metal becomes brittle after processing, or that cooling to cryogenic temperatures is required all describe conditions that do not apply to hot-working. Hence, the statement about large deformations occurring while the metal stays soft and ductile best describes hot-working.