GCr15 steel bearing collar bainite isothermal quenching technique

Abstract

Provided is an bainite austempering process of GCr15 steel bearing rings, which firstly heats GCr15 steel bearing rings to the temperature of 870 DEG C, then the GCr15 steel bearing rings are placed in the 50% KNO3+50%NaNo2 nitrate solution to be isothermal and is taken out after four hours of isothermal time. The bearing rings treated by the technology have high tenacity and long fatigue life. In particular, the service life of the working bearings under heavy load and impulse can be prolonged and the operation reliability of the bearings can be increased.

Description

technical field [0001] The invention belongs to the technical field of heat treatment, and in particular relates to a bainite austempering process for GCr15 steel bearing rings. Background technique [0002] Most domestic rolling mill bearings are made of GCr15 and GCr15SiMn bearing steels, using conventional martensitic quenching and tempering heat treatment processes. Due to the hard and brittle martensite structure, during the heat treatment process, the surface of the bearing ring is oxidized and decarburized, and the surface tensile stress is formed after quenching. The ring cracks often occur during transportation and collision between processes, and grinding cracks are easily formed during grinding; secondly , during the use of rolling mill bearings, they are subjected to large impact loads and harsh working conditions, and a considerable part of the inner and outer rings of the bearings are cracked and ribs are broken; moreover, the martensitic quenching workpiece ha...

AI Technical Summary

Problems solved by technology

Due to the hard and brittle martensite structure, during the heat treatment process, the surface of the bearing ring is oxidized and decarburized, and the surface tensile stress is formed after quenching. The ring cracks often occur during transportation and collision between processes, and grinding cracks are easily formed during grinding; secondly , during the use of rolling mill bearings, they are subjected to large impact loads and harsh working conditions, and a considerable part of the inner and outer rings of the bearings are cracked and ribs are broken; moreover, the martensitic quenching workpiece has large deformation, high scrap rate and grinding allowance Large, causing a lot of waste to the production of rolling mill bearings