Novel spheroidizing annealing technology for bearing steel wire

Abstract

The invention relates to a novel spheroidizing annealing technology for a bearing steel wire. The novel spheroidizing annealing technology comprises the steps that the bearing steel wire is arranged in a cover-type furnace, a heat treatment furnace is filled with nitrogen, then nitrogen filling is stopped, the heat treatment furnace is filled with hydrogen, the heat treatment furnace is heated tothe high temperature T0 firstly, T0 is 780 to 800 DEG C, heat preservation is conducted for 0.5-5 h, meanwhile, technology nitrogen filling is stopped, then the temperature is controlled at the heat preservation stage, uniform heating is controlled at 780+ / -2 DEG C, and heat preservation treatment is conducted for 5-7 h; first-stage cooling is conducted, specifically, the interior of the furnace is cooled to 700- 720 DEG C at the speed of 50+ / -4 DEG C / h, and heat preservation is conducted for 1 h; second-stage cooling is conducted, specifically, the interior of the furnace continues being cooled to 650 DEG C at the speed of 12.5+ / -2 DEG C / h, and heat preservation is not conducted; third-stage cooling is conducted, specifically, the interior of the furnace continues being cooled to 300 DEGC at the speed of 230+ / -10 DEG C / h, meanwhile, water spraying for cooling is started, and heat preservation is not conducted; and fourth-stage cooling is conducted, specifically, the interior of the furnace continues being cooled to 150 DEG C at the speed of 70+ / -10 DEG C / h, and a product is taken from the furnace. According to the novel spheroidizing annealing technology, the annealing period ofthe bearing steel wire is shortened, and the annealing capacity is increased.

Description

technical field [0001] The invention relates to an annealing process of metal materials, in particular to a spheroidizing annealing process of a novel bearing steel wire. Background technique [0002] Spheroidizing annealing is one of the basic ways to improve the structure and properties of steel. The main purpose of spheroidizing annealing is to spheroidize carbides in the microstructure of steel materials, reduce the hardness of materials, improve the plasticity of materials, and reduce the deformation resistance of materials. , making the material easy to be plastically formed. Bearing steel wire is mainly used to manufacture rolling elements or ferrules of rolling bearings. The key is to select a suitable spheroidizing annealing process. [0003] Spheroidizing annealing is the process of heating the steel to 20-30°C above AC1, keeping it warm for an appropriate time, and then cooling slowly with the furnace to finally obtain spherical pearlite. [0004] In the traditi...

AI Technical Summary

Problems solved by technology

[0004] In the traditional spheroidizing annealing process, the heating and cooling process of the entire annealing process has a long process cycle, and the annealing capacity is severely compressed

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