Effect of quenching method on deformation of thin-walled bearing rings

With the development of science and technology, the working environment of the bearing is more and more complicated, and higher requirements are placed on the performance of the bearing. The deformation problem caused by the quenching of the bearing ring has not been solved very well, which not only seriously affects the bearing quality, but also greatly increases the workload of the whole deformation. In order to ensure the size of the quenching ferrule, it is necessary to increase the amount of grinding. Although the qualification rate of the quenching ferrule is improved to some extent, the grinding work is increased, and the loss of the material is also increased.

There are many factors affecting the deformation of the ferrule. The ferrule is inevitably affected by factors such as thermal expansion and contraction stress, turning stress release, ferrule weight, cooling medium flow impact, and structural transformation stress during quenching. Deformation [1-3]. According to the appearance of the ferrule, the deformation can be divided into: expansion and contraction deformation, elliptical deformation, warping deformation and taper deformation. There is a correspondence between different deformations, and controlling one of the deformations may bring about another deformation. In addition, the thin-walled ferrules have relatively poor stiffness and are therefore highly susceptible to deformation during cooling [4-6].

In this paper, the effects of elliptical deformation and warpage deformation of thin-walled bearing rings are analyzed by different quenching methods, and the law is found to provide a theoretical basis for actual production.

1 Test method

The hardening test of the 71868/01 thin-walled bearing ring was carried out by three kinds of quenching methods. The quenching of the ferrule required elliptical deformation and warpage deformation to be controlled at ≤0.7 mm, and the deformation amount was less than 0.7 mm. Measure the results and analyze the cause of the deformation.

The salt bath quenching test heating device is a box type controlled atmosphere salt quenching multi-purpose furnace. The heat treatment process is: 830 °C, 30 min, 170 °C, molten salt quenching, 15 min, air-cooled to room temperature. The layout is flat, 1 layer is placed, and 72 pieces are installed.

The quenching test heating equipment is a box-type controlled atmosphere oil quenching multi-purpose furnace [7-9]. The heat treatment process is: 830 °C heat preservation 30 min 80 °C classification quenching oil quenching for 15 min direct deformation. The layout is flat, 1 layer is placed, and 72 pieces are installed.

Rotary quenching machine oil quenching test heating equipment is box type high temperature furnace. The heat treatment process is: 830 °C for 30 minutes, rotary quenching machine oil quenching (1 min quenching for 1 min) direct deformation. The layout is flat, 1 layer is placed, and 72 pieces are installed.