Title:
HEAT TREATMENT PROCESS FOR INCREASING RESILIENCE OF BEARING STEEL
Document Type and Number:
WIPO Patent Application WO/2018/103079
Kind Code:
A1
Abstract:
A heat treatment process for increasing the resilience of a bearing steel, comprising the following steps: S1 annealing: a steel material is kept warm at 880-1000 °C for 4-6 h, with the temperature being cooled at a rate of 25-45 °C/h to 800-860 °C, kept warm for 1-2h, then with the temperature being cooled at a rate of 20-30 °C/h to 600-700 °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 750-820 °C, the steel material is placed therein, kept warm for 2-4 h, and removed from the furnace for air cooling; S3, quenching: under the protection of nitrogen gas, the steel material is kept warm at a temperature of 1000-1100 °C for 1-2 h, then rapidly quenched into an oil of 100-220 °C for cooling, thus allowing a carbide to be evenly distributed, and the steel material is removed when the temperature thereof drops to 150-180 °C and then air cooled; S4, primary freeze treatment: the steel material of S3 is cold treated at a temperature of −73 °C for 1-2 h; and S5, primary tempering: placing the steel material into a tempering furnace and, with the tempering furnace being heated to 150-170 °C, kept warm for 1-3 h. The bearing steel prepared per the process is of increased purity and has a reduced amount of impurities, fine and diffused carbides, a uniform size, and significantly increased resilience.
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Inventors:
ZHANG KANG (CN)
YE YONG (CN)
YE YONG (CN)
Application Number:
PCT/CN2016/109248
Publication Date:
June 14, 2018
Filing Date:
December 09, 2016
Export Citation:
Assignee:
QINGDAO BRANCH CO LTD OF MECHANICAL SCIENCE RES INSTITUTE (CN)
International Classes:
C21D1/00; C21D1/18; C21D1/26; C21D1/28; C21D1/58; C21D6/04; C21D9/00
Foreign References:
| CN101947630A | 2011-01-19 | |||
| EP0861907B1 | 2001-08-16 | |||
| CN106555040A | 2017-04-05 | |||
| CN104328250A | 2015-02-04 |
Attorney, Agent or Firm:
QINGDAO ZHIJIA INTELLECTUAL PROPERTY AGENCY FIRM (GENERAL PARTNERSHIP ) (CN)
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