After-forged heat treatment technique of 9Cr2MoV chilled roll steel

Abstract

The invention relates to an after-forged heat treatment method of 9Cr2MoV chilled roll steel. The after-forged heat treatment method is characterized in that a chilled roll is made of 9Cr2MoV steel, the after-forged heat treatment method comprises the steps of normalizing and spheroidizing annealing, wherein the normalizing technique is performed at the temperature of 950 DEG C, higher temperature facilitates the dissolution of carbide and ensures the homogeneity of compositions. When normalization cooling is performed, the chilled roll is hoisted and cooled by atomizing water so as to prevent formation of continuous network carbide on grain boundary; in the spheroidizing annealing, fine carbide is easily molten from the middle through 820 DEG C insulation, so as to form a great amount of diffusely distributed carbide particles; carbide, as heterogeneous nucleus, is continuously separated out by austenite through retarded cooling, a carbon enrichment region of the austenite is formed into carbide crystal nucleus grown crystal grains, finally, the carbide crystal nucleus grown crystal grains are gathered and grown into particular cementite with certain size through 730 DEG C constant temperature, so that an excellent spheroidized structure can be obtained.

Description

technical field [0001] The invention relates to a post-forging heat treatment process of 9Cr2MoV cold roll steel. Background technique [0002] The roll is the main consumable spare part of the rolling mill, and the quality of the roll is an important factor affecting the quality of the rolled material and the cost consumption of the rolling mill. Cr2 series steel rolls are the most used parts in domestic rolling mills at this stage, and the roll body is often processed through annealing, rough turning, quenching and tempering, semi-finishing turning, surface quenching and other processes. Cold-rolled products play a very important role in the national economy because of their good product performance, high finish, and good surface quality. The quality and service life of the main tool rolls for direct processing of metals are directly related to rolling production. Production efficiency, product quality and production cost. At present, there is a certain gap between domes...

AI Technical Summary

Problems solved by technology

However, when the cold rolls made of large-size forging blanks are used, some cracks will be found during rough turning, and the cracking phenomenon will become more serious as the size of the forging blank increases.

This is due to the defects (band segregation, network carbide, etc.) left over from the forging of large-size cold rolls, which cannot be completely eliminated by conventional heat treatment processes, resulting in cracking of the rolls

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