Quenching method for large-specification working roller of high-alloy cold-work die steel

Abstract

The invention discloses a quenching method for a large-specification working roller of high-alloy cold-work die steel, and belongs to the steel processing field. The quenching method comprises the following steps: performing continuous induction thermal treatment on the working roller, quickly rising the temperature of the surface of the working roller to 1020-1100 DEG C, and performing fog cooling when the temperature is risen to a preset temperature; continuously performing fog cooling for 50-70 minutes; and guaranteeing a re-heating temperature to be not higher than 100 DEG C. The quenchingmethod disclosed by the invention is free of pollution, is low in requirement on needed equipment; surface hardness of the working roller is great, toughness of the core part of the working roller ishigh, a transitional layer is transitional in a gradient mode at uniform reducing hardness, loading requirements are met, continuous induction quenching of the roller body is realized while cracks are avoided, a thermal treatment success rate is increased, and production cost is reduced.

Description

technical field [0001] The invention relates to a quenching method, in particular to a quenching method for large-size cold-rolled work rolls of high-alloy cold-working die steel, and belongs to the field of steel processing. Background technique [0002] With the continuous development of cold rolling technology and the improvement of product quality requirements, the requirements for roll performance are also getting higher and higher. In order to obtain high-performance rolls, the alloy content of the rolls is getting higher and higher, especially for the work rolls used for black skin rolling. The material of the work rolls of the multi-roll mills represented by the 18-high machine is mainly cold work die steel. Cr12Mo1V1, Cr12MoV or M2. Due to its large size and extremely high alloy content, the existing forging process cannot pulverize the carbides well, resulting in a large amount of eutectic carbides distributed in the shape of herringbones or bands in the matrix. ...

AI Technical Summary

Problems solved by technology

In order to improve the performance of the roll and improve the uniformity of eutectic carbides, the roll preparation process needs to optimize the quenching (heat treatment) method, and the most ideal quenching method is salt bath furnace or atmosphere furnace quenching, but its high equipment costs and environmental pollution , which brings a great burden to the enterprise, especially when the product batch is small, it also reflects the disadvantages of overall quenching

[0004] The existing work roll preparation process is batching-billet making-rough turning-continuous multiple heating-cooling-high temperature quenching-tempering. According to the existing technology, use intermediate frequency equipment to test and produce work rolls made of Cr12MoV , it has been proved by practice that when the roll diameter is greater than 170mm, the roll quenching longitudinal cracking rate is above 50%, and the larger the diameter, the greater the quenching risk; the hardness and metallographic structure of the finished product are tested, and the result is that the hardness is low, And there are a lot of eutectic carbides with uneven distribution, and the quality of the roll surface is low

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