(1) In order to make the steel have high plasticity, toughness and appropriate strength, the steel is tempered at a high temperature of about 400-500 °C, and the steel which is sensitive to temper brittleness must be rapidly cooled after tempering to suppress tempering. Brittleness occurs.
(2) If the part is required to have a particularly high strength, it is tempered at about 200 ° C to obtain a medium carbon tempered martensite structure.
(2) Spring steel:
1. Quenching: oil quenching at 830-870 °C.
2. Tempering: tempering at about 420-520 °C to obtain tempered troostite structure.