Operation method: The quenched seamless steel pipe is cooled to -60 to -80 degrees or lower in a low temperature medium (such as dry ice, liquid nitrogen), and the temperature is uniform and then the temperature is taken to room temperature.
Objective: 1. Convert all or most of the retained austenite in the quenched seamless steel pipe to martensite, thereby improving the hardness, strength, wear resistance and fatigue limit of the seamless steel pipe;
2. Stabilize the structure of the steel to stabilize the shape and size of the seamless steel pipe.
Application points: 1. After quenching, the seamless steel tube should be cold-treated immediately, and then tempered at low temperature to eliminate the internal stress during low-temperature cooling.
2. Cold treatment is mainly applied to compact tools, gauges and compact parts made of alloy steel.
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