Which term refers to the process of hardening a steel and then tempering to adjust toughness?

Which term refers to the process of hardening a steel and then tempering to adjust toughness?

• A. Hardening and tempering
• B. Heat treatment
• C. Annealing
• D. Nitriding

Answer: (A)

Hardening and tempering is a heat-treatment sequence used to raise hardness and then tune toughness. In this approach, steel is heated into its austenite range and quenched to form martensite, which makes it very hard but brittle. Tempering then reheats it to a lower temperature to relieve internal stresses and allow some diffusion, reducing hardness slightly and increasing toughness to the desired level. This combination—hardening to gain hardness, then tempering to adjust toughness—is exactly what the term describes. The broader term heat treatment covers many processes, but it doesn’t specify this specific sequence. Annealing softens steel, and nitriding hardens the surface without the same tempering step to adjust toughness.

Hardening and tempering is a heat-treatment sequence used to raise hardness and then tune toughness. In this approach, steel is heated into its austenite range and quenched to form martensite, which makes it very hard but brittle. Tempering then reheats it to a lower temperature to relieve internal stresses and allow some diffusion, reducing hardness slightly and increasing toughness to the desired level. This combination—hardening to gain hardness, then tempering to adjust toughness—is exactly what the term describes. The broader term heat treatment covers many processes, but it doesn’t specify this specific sequence. Annealing softens steel, and nitriding hardens the surface without the same tempering step to adjust toughness.