High-strength high-impact toughness bearing steel and its heat treatment process

Abstract

The chemical composition of said invented high-strength high impact toughness bearing steel contains: C 0.6-1.0, Si 0.7-1.8, Mn 0.3-0.85, Cr 0.1-1.9, MO 0.15-0.8, V 0.15-0.6,l W, 0.1-0.6, rare earth 0.01-0.20, S is less than or equal to 0.25, P is less than or equal to 0.025 and the rest is Fe and inevitable impurity. Said invention adopts a simple high-frequency surface quenching process, and can attain the performance requirements of bearings used in the roll mill, railway machines, petroleum machines and mine machines under the condition of large load and heavy impact.

Description

technical field [0001] The invention belongs to the technical field of steel materials and processing technology thereof, and mainly relates to high-strength, high-impact-toughness bearing steel and a heat treatment process suitable for the steel type. Background technique [0002] At present, bearings with large loads and heavy impacts are manufactured domestically, such as rolling mills in steel mills, railway rolling stock, and bearings on machinery such as mines and petroleum. The existing technologies are: [0003] 1. The material used is GCr 18 Mo and 20Cr in carburized steel 2 Ni 4 A, 20Cr 2 Steel such as NiMoA. [0004] 2. The heat treatment used in bearing production has a negative effect on GCr 18 Mo et al. used isothermal treatment to obtain lower bainite or lower bainite martensite structure, and the time required for heat treatment was generally four to five hours. And for 20Cr 2 Ni 4 A. Isocarburized steel is carburized, and the heat treatment time is f...

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Problems solved by technology

[0008] With isothermal treatment, if it is isothermal at 10 °C above the Ms point, the lower bainite structure can be obtained after 10 hours of isothermal treatment, and 4 hours is required for isothermal treatment at a temperature of 50-60 °C above the Ms point. And isothermal treatment, if you use salt bath, after quenching, you need to increase the process of cleaning the salt film on the surface of the workpiece, which is more complicated than direct high-temperature quenching

[0009] Judging from the isothermal and carburizing heat treatment processes commonly used for bearing steel, there are common problems such as long production cycle, high energy consumption, high raw material prices, low production efficiency, and complicated heat treatment processes.

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