Method for controlling carbide banded structure of high-carbon chromium bearing steel

Abstract

The invention discloses a control method for a high-carbon-chromium bearing steel carbide banded structure, and belongs to the field of bearing steel preparation. The method specifically comprises the following steps: obtaining a casting blank by adopting a crystallizer electromagnetic stirring and tail-section soft reduction process; the casting blank is placed in a heating furnace to be subjected to primary high-temperature diffusion; the casting blank is subjected to cogging rolling, a rolled intermediate blank is subjected to secondary high-temperature diffusion, during cogging rolling of the casting blank, the cogging process of the casting blank is controlled to be seven passes, the first three passes adopt a large reduction process, the reduction rate of the first pass is controlled to be 28-30%, the reduction rate of the second pass is controlled to be 22-24%, and the reduction rate of the third pass is controlled to be 26-28%; then the rolled intermediate billet is put into a heating furnace for secondary high-temperature diffusion; the heating temperature of the secondary high-temperature section is controlled to be 1170-1230 DEG C, the total heating time is controlled to be 200-280 min, and the time of the high-temperature section is 110-190 min; and then a continuous rolling mill is adopted for rolling, and the bearing steel with the carbide banded grade CZ7 smaller than or equal to 7.3 grade is obtained.

Description

technical field [0001] The present application relates to the field of bearing steel preparation, in particular to a method for controlling the carbide band structure of high-carbon chromium bearing steel. Background technique [0002] Bearing steel is an important basic component of the machinery industry. It is usually used to manufacture balls, rollers and bearing rings. It is under great pressure and friction during work, so bearing steel is required to have high and uniform hardness and wear resistance , and a high elastic limit. In the production, the requirements for the uniformity of the chemical composition of the bearing steel, the content and distribution of non-metallic inclusions, and the distribution of carbides are very strict. [0003] For high-carbon chromium bearing steel, it is mainly to improve the cleanliness of the steel and fully homogenize the carbides in the steel. Carbide segregation is an important indicator to reflect the uniformity of bearing s...

AI Technical Summary

Problems solved by technology

This method can improve the strip quality, but due to the high-temperature diffusion of the slab, the crystalline segregation of primary carbides has insufficient dissolution, resulting in unstable control of the carbide strip level, and high levels (CZ7≥7.6) often occur ) carbide strips, which cannot stably meet the requirements of high-end customers CZ7≤7.4, or even CZ7≤7.3

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