Long-service-life railway bearing steel and preparation method thereof

Abstract

The invention discloses long-service-life railway bearing steel. The steel comprises the following chemical components in percentage by weight: 0.17 to 0.23 percent of C, 0.15 to 0.40 percent of Si, 3.0 to 3.8 percent of Mn, 0.35 to 0.65 percent of Cr, 0.6 to 0.9 percent of Ni, 0.20 to 0.30 percent of Mo, less than or equal to 0.30 percent of Cu, 0.05 to 0.20 percent of V, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S and the balance of Fe and impurities. In addition, the invention further provides a preparation method of the long-service-life railway bearing steel, and the method mainly comprises the steps of forging, carburizing treatment, primary quenching and tempering and isothermal quenching. According to the long-service-life railway bearing steel and the preparation method thereof, the residual austenite and the grain structure are reasonably regulated and controlled, so that the surface structure of the steel is bainite, acicular martensite, nano austenite and acicular carbide. The steel has good obdurability matching and excellent contact fatigue performance.

Description

technical field [0001] The invention belongs to the technical field of bearing manufacturing, and in particular relates to a long-life railway bearing steel and a preparation method thereof. Background technique [0002] In order to meet the work requirements of saving expenses, reducing consumption and reducing costs, the railway freight car bearing has started the reform of the repair system, which requires a substantial extension of the bearing maintenance cycle, which is bound to put forward higher requirements for bearing quality control. Heavy-duty railway bearings are subjected to heavy loads and shock loads and are used in harsh environments. Fatigue spalling on the bearing surface is the main failure mode of high-speed rail axlebox bearings, which has a great relationship with the inherent quality of bearing steel, which determines that the inherent quality of bearing steel is mainly concentrated in the steel smelting level and heat treatment process. The smelting ...

AI Technical Summary

Problems solved by technology

[0003] Martensite is widely used in high-strength and high-hardness industrial fields, but martensite has poor plasticity and fracture toughness

Tempering is a common means of improving toughness, but stress relaxation and carbide precipitation will reduce the strength of martensite

Images