Water quenching and air cooling modified treatment technology of 42CrMo material

Abstract

The invention discloses a hardening and tempering and quenching treatment process of a large 42CrMo forged piece, which comprises the steps of heating up, heat preservation, quenching, high temperature tempering, etc. Quenching is carried out by a water quenching and air cooling method. The process comprises the following specific steps: when quenching, the forged piece is cooled in water for a certain time, and then is taken out for air cooling and buffer; when the surface temperature returns to 200-300 DEG C, the forged piece is put into water for water cooling again, and then is taken out for air cooling and buffer; after a plurality of cycles of water cooling and air cooling, the temperature of the forged piece is stable and not over 300 DEG C, the quenching process is completed. The treatment process provides the hardening and tempering scheme of the forged piece under the quenching condition without an oil groove, quenching oil, and the like, and improves the comprehensive properties of the forged piece.

Description

technical field [0001] The invention relates to a quenching and tempering treatment method of 42CrMo material, in particular to a water-quenching and air-cooling quenching and tempering treatment process method of 42CrMo material applied to large forgings. Background technique [0002] 42CrMo material is a commonly used metal material. The quenching and tempering process of this material generally includes: heating, heat preservation, quenching, high temperature tempering and other steps. The following problems are prone to occur during the quenching and tempering process: 1. Uneven hardness; 2. Quenching is easy Make the crack expand; 3. The organization is unqualified; 4. The comprehensive mechanical properties are unqualified. Usually for small 42CrMo materials, oil quenching or water quenching can be used to improve material properties. In order to avoid various quenching and tempering problems, 42CrMo quenching of large forgings usually uses oil quenching to improve it...

AI Technical Summary

Problems solved by technology

[0002] 42CrMo material is a commonly used metal material. The quenching and tempering process of this material generally includes: heating, heat preservation, quenching, high temperature tempering and other steps. The following problems are prone to occur during the quenching and tempering process: 1. Uneven hardness; 2. Quenching is easy Make the crack expand; 3. The organization is unqualified; 4. The comprehensive mechanical properties are unqualified

In order to avoid various quenching and tempering problems, 42CrMo quenching of large forgings usually uses oil quenching to improve its comprehensive mechanical properties, while oil quenching requires relatively high levels of equipment and oil tanks, strong safety requirements, and high oil costs. Pollution is also relatively large, so there are certain limitations in the oil quenching method. It is difficult to complete the quenching and tempering process in the absence of oil tank quenching conditions or without oily media.

For large 42CrMo forgings, the water quenching method is easy to form large internal stress due to the temperature difference between cold and hot, and it is easy to cause problems such as cold cracking.

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