弹垫的硝盐贝氏体等温淬火

Bainite Isothermal Quenching of Spring Sasher in Nitro-salt

大量的弹垫早期失效分析结果表明,80%以上的失效源自表面损伤、表面脱碳、表面腐蚀物、淬火组织不均匀和氢致延迟断裂,主要是内部应力集中度高。本文简述了采用硝盐贝氏体等温淬火工艺代替淬火加回火,这种工艺对于弹垫类的紧固件产品防止氢致延迟断裂有优势。通过生产实例表明,弹垫用贝氏体等温淬火工艺代替淬火加中温回火后,在同等载荷的轴向疲劳试验中,疲劳寿命从5万多次,提高至200万次以上。

The analysis results of early failure of a large number of spring washers indicate that more than 80% of the failures originate from surface damage, surface decarburization, surface corrosion, uneven quenching structure and hydrogen induced delayed fracture, mainly due to the high stress concentration in the part. In this paper, the substitution of bainite isothermal quenching process in nitro-salt for quenching and tempering is briefly described. This process has its advantages for the spring washers type fastener products to prevent hydrogen induced delayed fracture. Through the production example, the fatigue life of spring washer increases from more than 50,000 times to over 2 million times on the fatigue testing under the same load for the bainite isothermal quenching process to replace the quenching and medium temperature tempering.