High-carbon chromium bearing part surface peening thermal treatment method

Abstract

The invention relates to a heat treatment method, in particular to a high-carbon chrome bearing part surface intensified heat treatment method. The heat treatment method adopts the following steps: firstly, carbonitriding treatment: at the temperature of 830 to 850 DEG C, through adding 0.95 to 1.2C percent of carbon potential and 0.2 to 0.4m<3> / h of ammonia gas, a GCr15 bearing part is carbonitrided for 6 to 8 hours and then oil quenching is performed; secondly, high temperature tempering: at the temperature of 580 DEG C with the tolerance of 10 DEG C, high temperature tempering is implemented for 1.5 to 2.5 hours, and the bearing part is discharged from the furnace and air-cooled; thirdly, at the temperature of 820 DEG C with the tolerance of 10 DEG C, in the protective atmosphere of 0.95 to 1.2C percent of carbon potential and 0.2 to 0.4m<3> / h of ammonia gas, and the conventional secondary high temperature tempering is carried out. The invention has the advantages that a penetrating layer of 0.4 to 0.65mm can be achieved on the part surface through the method, in the obtained carbon nitrogen compound, the residual austenite amount is not less than 20 percent, the carbon nitrogen compound has 12 to 13 grade ultra fine grain size, the particle is difficult to differentiate under the optical microscope of 500 times, and the wear resistance and the anti-rolling contact fatigue lifetime of the bearing under the polluted lubrication environment are enhanced.

Description

Technical field [0001] The invention relates to a surface strengthening heat treatment method for metal parts, in particular to a surface strengthening heat treatment method for high-carbon chromium bearing parts. Background technique [0002] Bearings working in a polluted and lubricated environment are squeezed by various types of hard debris between the contacting rolling surfaces, and pits are formed on the rotating bearing raceway. Under the action of large interactive loads, the pits The edge forms very large contact stress, which accelerates the occurrence of fatigue damage, so the service life is shorter. [0003] At present, the average oxygen content in vacuum deoxidized bearing steel produced in China is about 10-12ppm, and the average oxygen content in continuous casting bearing steel materials produced by Jiangyin Xingcheng Steel Plant and Shanghai No. 5 Steel Plant is 6-8ppm, which is close to the advanced foreign countries Level. However, due to the substant...

AI Technical Summary

Problems solved by technology

However, in the production process of bearing steel in domestic steel mills, due to equipment and process reasons, the carbide particles in the produced bearing steel are relatively large, and the distribution is uneven, and some carbide bands and networks are serious, and even often It is found that there is a serious accumulation of carbides, which seriously affects the service life and reliability of the bearing