Which statement describes a consequence of cold working metal?

Which statement describes a consequence of cold working metal?

• A. Cold working can deform the metal structure and reduce ductility
• B. It increases ductility
• C. It improves electrical conductivity
• D. It makes it harder to machine

Answer: (A)

Cold working deformes metal at room temperature, which introduces dislocations in the crystal structure and causes strain hardening. This strengthens the metal but makes it less able to deform plastically, so its ductility is reduced. In other words, the structure is distorted and the material becomes less able to stretch before fracturing. While it can also increase hardness and sometimes make machining harder, the key consequence being tested is the loss of ductility due to the deformed structure.

Cold working deformes metal at room temperature, which introduces dislocations in the crystal structure and causes strain hardening. This strengthens the metal but makes it less able to deform plastically, so its ductility is reduced. In other words, the structure is distorted and the material becomes less able to stretch before fracturing. While it can also increase hardness and sometimes make machining harder, the key consequence being tested is the loss of ductility due to the deformed structure.