Rolling and cooling technology method for reducing GCR15 bearing steel zonary carbide level

Abstract

The invention discloses a rolling and cooling technology method for reducing GCR15 bearing steel zonary carbide level, which comprises the following steps: carrying out high temperature diffusion annealing after the die casting and the continuous casting of molten steel, keeping the temperature at 1260 DEG C for 1 to 3 hours, cogging blank into a slab or a square billet through blooming after the diffusion annealing, rolling the steel slab on a plank or a rod and wire mill in a heating furnace at the temperature of 1150 to 1200 DEG C for 1 to 2 hours in a multi-pass manner to roll into a finished steel product, wherein the roll beginning temperature of the rolling is not lower than 1120 DEG C, and the roll finishing temperature is not lower than 1020 DEG C, cooling through water immediately after the rolling, wherein the cooling temperature is not lower than 1000 DEG C, cooling the water to 620 to 660 DEG C, wherein the cooling speed is not lower than 50 DEG C per second, ascending the temperature to 780 DEG C along with the furnace by a spheroidizing annealing system to preserve heat for 40 minutes, and then cooling to the temperature of 650 DEG C to draw and wind-cool at the speed of 20 DEG C per second. Through the adoption of the bearing steels manufactured by the technology method, the level of the zonary carbide can be eliminated or reduced, and the requirement of the Chinese national standard can be well satisfied.

Description

technical field [0001] The invention relates to a bearing steel rolling and cooling process method, in particular to a rolling, cooling and heat treatment process method for reducing the level of GCr15 bearing steel strip-shaped carbides. Background technique [0002] Bearing steel is widely used. Due to its high contact fatigue and wear resistance, bearing steel is used in all walks of life, ranging from bearings in rolling mills to bearings in micro motors. Bearing steel is ubiquitous. The contact fatigue and wear resistance of bearing steel are mainly determined by the carbides in the structure. The status, size, and uniformity of distribution of carbides greatly affect the above-mentioned properties. Generally, bearing steel needs to be used after spheroidizing annealing. At this time, the carbides are basically distributed in the ferrite matrix in the form of spherical particles, but they will be distributed in bands along the rolling direction. The banded carbide...

AI Technical Summary

Problems solved by technology

[0003] After searching, domestic and foreign patents on bearing steel carbide control are mainly concentrated in the continuous casting stage and heating stage, and basically no corresponding research and patent application have been done in the rolling and cooling stages

Images