What is the process of heating a metal followed by slow cooling to toughen it and reduce brittleness called?

What is the process of heating a metal followed by slow cooling to toughen it and reduce brittleness called?

• A. Tempering
• B. Quenching
• C. Annealing
• D. Hardening

Answer: (C)

The process of heating metal followed by slow cooling to toughen it and reduce brittleness is known as annealing. During annealing, the metal is heated to a specific temperature, which allows for the rearrangement of its internal structure, helping to relieve internal stresses that may have formed during previous manufacturing processes. As the metal cools slowly, it results in a more uniform grain structure, enhancing ductility and reducing hardness, which can make the metal less prone to fracture. This is distinct from other processes like tempering, quenching, and hardening. Tempering specifically refers to the process of heating hardened steel to a temperature below its critical point to enhance its toughness, but this is not about the initial heating to toughen the material. Quenching involves rapidly cooling a heated metal, often in water or oil, which increases hardness but may also lead to increased brittleness if not followed by tempering. Hardening, as a term, typically describes the process of increasing the hardness of the metal through rapid cooling after heating, which is not the objective in this context.

The process of heating metal followed by slow cooling to toughen it and reduce brittleness is known as annealing. During annealing, the metal is heated to a specific temperature, which allows for the rearrangement of its internal structure, helping to relieve internal stresses that may have formed during previous manufacturing processes. As the metal cools slowly, it results in a more uniform grain structure, enhancing ductility and reducing hardness, which can make the metal less prone to fracture.

This is distinct from other processes like tempering, quenching, and hardening. Tempering specifically refers to the process of heating hardened steel to a temperature below its critical point to enhance its toughness, but this is not about the initial heating to toughen the material. Quenching involves rapidly cooling a heated metal, often in water or oil, which increases hardness but may also lead to increased brittleness if not followed by tempering. Hardening, as a term, typically describes the process of increasing the hardness of the metal through rapid cooling after heating, which is not the objective in this context.