Controlled-forging controlled-cooling processing technology of bearing ring prepared by GCr15

Abstract

The invention relates to a controlled-forging controlled-cooling processing technology of a bearing ring prepared by GCr15, comprising the following steps of: quenching the bearing ring in cooling fluid at final forging temperature of 850-950 DEG C and at fluid outlet temperature of 350-550 DEG C; when heating the bearing ring to the temperature of 450-550 DEG C, after preserving the temperature for 1h-3h, discharging the bearing ring from a boiler and cooling the bearing ring to room temperature; when heating the bearing ring to the temperature of 650-690 DEG C again, preserving the temperature for 1h; when continuously heating the bearing ring to the temperature of 740-780 DEG C, after preserving the temperature for 2-3h, cooling the bearing ring to the temperature of 680-690 DEG C and preserving the temperature for 2-4 hours; finally, when cooling the bearing ring to the temperature of 550-600 DEG C at the speed of 10 DEG C / h, cooling o the bearing ring to the room temperature along with the boiler by air; quenching a machined semi-finished bearing ring; when heating to the temperature of 810-830 DEG C, after preserving the temperature for 45-60min, discharging the machined semi-finished bearing ring from the boiler and quenching the machined semi-finished bearing ring in oil; and when heating the machined semi-finished bearing ring to the temperature of 160-200 DEG C after being quenched, preserving the temperature of the machined semi-finished bearing ring for 4h, discharging the machined semi-finished bearing ring from the boiler and cooling the machined semi-finished bearing ring to the room temperature by air. According to the invention, carbides, martensite crystals and austenite crystals of the bearing ring are refined, network carbides are improved or eliminated and impact ductility and fatigue life are improved.

Description

technical field [0001] The invention belongs to the technical field of bearing heat treatment, in particular to a controlled forging and controlled cold processing process for making bearing rings made of GCr15. Background technique [0002] The composition of high carbon chromium bearing steel GCr15 (1.0-C, 1.5-Cr) by weight percentage is as follows: [0003] C: 0.90-1.05%, Si: 0.55-0.65%, Mn: 1.00-1.10%, Cr: 1.35-1.50%, Mo≯0.10%, P≯0.025%, S≯0.025%, Ni≯0.30%, Cu≯ 0.25%, Ni+Cu≯0.50%, the rest is Fe and unavoidable impurities. [0004] GCr15 is the most used bearing steel variety in various countries for many years, because GCr15 has the characteristics of excellent rolling fatigue performance, high hardness and good wear resistance. However, the continuous casting GCr15 bearing steel produced in my country is limited by the production equipment, and the high-temperature diffusion annealing time is far from enough. Therefore, the mesh and banded carbides of the bearing ste...

AI Technical Summary

Problems solved by technology

However, in the process of making bearing rings, there will be a certain amount of coarse eutectic carbides in the internal crystal structure of GCr15 steel, which will significantly reduce the rolling fatigue life and strength and toughness of bearing rings.

At the same time, the carbide, martensitic structure and austenite grains of the GCr15 bearing ring under the conventional processing technology are too large, which cannot achieve the best match between the strength and toughness of the finished bearing ring, and also restricts the bearing ring. Rolling fatigue life and toughness