30CrMnSiA自锁螺母裂纹原因分析

Fracture Analysis of 30CrMnSiA Self-Locking Nut

摘要: 本文对30CrMnSiA自锁螺母试验裂纹进行了宏观观察、断口扫描电镜观察和能谱分析，并结合了工艺试验进行了综合分析，结果表明：产生试验裂纹的根本原因是表面镀锌的螺母和表面镀镉的试验螺栓在300℃进行加温加载锁紧性能试验时发生液态金属致脆，采用表面镀锌的试验螺栓配合可有效避免类似的试验裂纹。

Abstract: The test fractures of 30CrMnSiA self-locking nut were inspected by the macro-observation, scanning electronic microscope (SEM) observation and energy spectrum analysis. Then, an overall analysis by synthesis method was conducted in combination with process tests. Finally, the results show that: the root cause for test fractures is liquid-metal embrittlement which may be occured when the zinc-plated nut fitted with a cadmium-plated test bolt is loaded and heated to test locking properties at 300˚C, and similar test fractures on the nut can be avoided effectively by mating with a zinc-plated test bolt.