What type of process is tempering?

What type of process is tempering?

• A. Hardening
• B. Annealing
• C. Toughening
• D. Welding

Answer: (C)

Tempering is a heat-treatment performed after hardening to reduce brittleness and improve toughness in steel. When steel is quenched, it becomes very hard but also very brittle due to martensite formation and internal stresses. Reheating to a lower, controlled temperature and holding allows those stresses to relieve and the microstructure to transform into tempered martensite with finely dispersed carbides. The result is a material with a better balance of hardness and toughness, which is why tempering is described as a toughening step. The exact tempering temperature and time control how much hardness remains versus how much toughness is gained. This differs from annealing, which aims to soften more completely; from hardening, which is the hardening step itself; and from welding, which is a joining process unrelated to this heat treatment.

Tempering is a heat-treatment performed after hardening to reduce brittleness and improve toughness in steel. When steel is quenched, it becomes very hard but also very brittle due to martensite formation and internal stresses. Reheating to a lower, controlled temperature and holding allows those stresses to relieve and the microstructure to transform into tempered martensite with finely dispersed carbides. The result is a material with a better balance of hardness and toughness, which is why tempering is described as a toughening step. The exact tempering temperature and time control how much hardness remains versus how much toughness is gained. This differs from annealing, which aims to soften more completely; from hardening, which is the hardening step itself; and from welding, which is a joining process unrelated to this heat treatment.