heat treatment
Time：2022/5/17 Browse：2029
Normalizing: the purpose of normalizing is to refine the grain, reduce the banded degree in the structure, and adjust the hardness to facilitate machining. After normalizing, the steel has fine grain pearlite structure.
Quenching: heat the steel body to about 850 ℃ for quenching. The quenching medium can be selected according to the size of steel parts and the hardenability of the steel. Generally, water or oil or even air quenching can be selected. The steel in the quenched state has high hardness, low plasticity and large internal stress.
Tempering: in order to make the steel have high plasticity, toughness and appropriate strength, the steel is about 400-500 ℃
For high temperature tempering, the steel with high sensitivity to tempering brittleness must be cooled quickly after tempering to restrain the occurrence of tempering brittleness; If the parts are required to have particularly high strength, temper at about 200 ℃ to obtain tempered martensite structure.
Quenching and tempering: high temperature tempering after quenching (500-650 ℃). This process is usually used for high-strength bolts.
Spring steel: medium temperature tempering after quenching (420-520 ℃)
Quenching: oil quenching at 830-870 ℃.
Tempering: tempering at about 420-520 ℃ to obtain tempered troostite structure.
Carburizing: quenching after carburizing and low temperature tempering (150-250 ℃)
Carburizing: a kind of chemical heat treatment, which refers to the infiltration of element C into the surface of steel parts at a certain temperature in an active medium containing a certain chemical element. Partial preheating (850 ℃) carburizing (890 ℃) diffusion (840 ℃) process
Quenching: for carbon and low alloy carburized steel, direct quenching or one-time quenching is generally adopted.
Tempering: low temperature tempering to eliminate internal stress and improve the strength and toughness of carburized layer.
