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1. (WO2018103080) HIGH-CARBON CHROMIUM BEARING STEEL HEAT TREATMENT PROCESS

Pub. No.:    WO/2018/103080    International Application No.:    PCT/CN2016/109252
Publication Date: Fri Jun 15 01:59:59 CEST 2018 International Filing Date: Sat Dec 10 00:59:59 CET 2016
IPC: C21D 1/28
C22C 38/54
Applicants: ZHANG, Kang
张康
YE, Yong
叶永
Inventors: ZHANG, Kang
张康
YE, Yong
叶永
Title: HIGH-CARBON CHROMIUM BEARING STEEL HEAT TREATMENT PROCESS
Abstract:
A heat treatment process for a high-carbon chromium bearing steel. The composition of the high-carbon chromium bearing steel comprises raw materials of the following mass percentages: C: 1.1%-2.2%; Mn: 0.1%-1.0%; B: 0.3%-1.3%; Ni: 0.1%-1.1%; Si: 1.1%-1.5%; Ti: 0.2%-0.5%; Cr: 3.5%-5.5%;Al: 0.15%-0.19%; Be: 0.1%-0.2%; and the remainder being Fe. The heat treatment method comprises the following steps: S1, annealing: a steel material is kept warm at 880-960 °C for 1-5 h, with the temperature being cooled at a rate of 40-60 °C/h to 700-800 °C, kept warm for 1-2 h, and then removed from a furnace for air cooling; S2: normalization: the temperature in the furnace is raised to 780-840 °C, the steel material is placed therein, kept warm for 2-4 h, and removed from the furnace for air cooling; and S3, carburization: the steel material is preheated to 120-180 °C and then undergoes a carburization treatment. The process allows a carbide to be further reduced in size and evenly distributed, the content of retained austenite to be low, and the resulting bearing steel to have a significantly extended service lift and to be adaptable for use in different environments.