Spheroidized annealing technology for GCr15 bearing steel

Abstract

The invention relates to a spheroidized annealing technology for GCr15 bearing steel. The GCr15 bearing steel comprises the following components in percentage by mass: 0.95 to 1.05 percent of C, 0.25 to 0.45 percent of Mn, 0.15 to 0.35 percent of Si, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, 1.40 to 1.65 percent of Cr, less than or equal to 0.10 percent of Mo, less than or equal to 0.30 percent of Ni, less than or equal to 0.25 percent of Cu, less than or equal to 0.50 percent of Ni and Cu, and the balance of Fe. The spheroidized annealing technology for the GCr15 bearing steel is characterized by comprising the following steps of: heating the components to the temperature of between 790 and 800 DEG C together with a furnace, and performing high-temperature heat preservation at the temperature; cooling the heated components to the temperature of 725+ / -5 DEG C, and performing intermediate-temperature heat preservation; and slowly cooling to thetemperature of 630 DEG C, quickening the cooling rate, cooling to the temperature of below 520 DEG C, discharging and performing air cooling. The technology is simple, the structure and the mechanical properties of the GCr15 bearing steel are suitable for subsequent plastic processing forming, and a structure preparation is made for final quenching and tempering.

Description

technical field [0001] The invention relates to a heat treatment process for a hot-rolled bar of bearing steel, in particular to a spheroidizing annealing process for a hot-rolled bar of GCr15 bearing steel. Background technique [0002] The main purpose of spheroidizing annealing of bearing steel is to spheroidize the carbides in the microstructure of the steel material, reduce the hardness of the material, improve the plasticity of the material, reduce the deformation resistance of the material, and make the material easy to plastically form. [0003] GCr15 steel is a traditional high-carbon chromium bearing steel mainly used to manufacture balls, rollers and rings of various bearings. After hot rolling of GCr15 bearing steel hot-rolled bars, the subsequent plastic processing and quenching need to undergo spheroidizing annealing treatment to soften the material, reduce deformation resistance, and prevent quenching cracking and deformation. The purity and uniformity of hig...

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Problems solved by technology

There are many researches on the spheroidizing annealing process. Among the existing spheroidizing annealing processes, the continuous spheroidizing annealing process and the isothermal spheroidizing annealing process require a long annealing time, and the annealing process after austenitization requires 10 to 16 hours. The traditional spheroidizing annealing process of high-carbon chromium bearing steel generally takes 17 hours, and the spheroidizing quality is unstable

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