An optimization method of water quenching process for alloy steel

Abstract

The invention provides an optimization method of an alloy steel water quenching process. The method comprises the following steps of firstly predicting and obtaining a structure with a required performance; determining the temperature to be cooled of the structure by virtue of an isothermal transformation cooling curve of an alloy steel part material; dividing the alloy steel part into a fast cooling region and a slow cooling region along the section from surface to center, wherein the fast cooling region is a part from the surface of the alloy steel part to the required performance part or deeper, the slow cooling region is a part of the required performance part or the deeper part to a central; determining water cooling time for reducing to a preset temperature of the fast cooling regionby means of numerical simulation, optimizing water cooling time by combining the temperature returning temperature and surface stress state of the required performance part; and finally, giving out the alloy steel water quenching process. According to the method, the purpose that low / high hardenability workpiece with limited material hardenability and large size can obtain high quenching coolingperformance or the purpose of avoiding generation of quenching cracks in quenching and cooling process are met.

Description

technical field [0001] The invention relates to the field of steel heat treatment, in particular to an optimization method for a water quenching process of alloy steel. Background technique [0002] Quenching and tempering is a traditional process, which heats alloy steel parts to the austenite zone, then quenches and cools to room temperature to obtain martensite or bainite structure, and then tempers at a suitable temperature to obtain tempered Martensite or tempered bainite structure. For alloy steel quenching, oil is generally used as the quenching medium to avoid cracking. The problem is that the mechanical properties of oil quenching are much lower than that of water quenching. At the same time, oil quenching has the risk of oil smoke pollution and fire. Therefore, water quenching of alloy steel parts is the future development direction, and the premise of promoting the water quenching process is to solve the problem of water quenching cracking. [0003] After search...

AI Technical Summary

Problems solved by technology

For alloy steel quenching, oil is generally used as the quenching medium to avoid cracking. The problem is that the mechanical properties of oil quenching are much lower than that of water quenching. At the same time, oil quenching has the risk of oil smoke pollution and fire.

However, for large-sized medium-low hardenability alloy steel, the performance part is required to be in the deep part, and this process cannot meet the requirements.