某卡车轮胎的铜合金气门嘴在使用1~3个月后部分发生开裂。采用宏观检验、化学成分分析、金相检验、硬度测试、断口分析及能谱分析等方法对气门嘴开裂的原因进行了分析。结果表明: 气门嘴经过冷加工变形后没有去应力退火, 在应力和环境介质的共同作用下, 发生了应力腐蚀开裂。

The copper alloy air valve of truck tires in the use of 1~3 months later had cracked partly. The cracking reasons was investigated by means of macroscopic examination, chemical composition analysis, metallographic examination, hardness testing, fracture analysis and energy spectrum analysis.The results showed that the air valve cracking was stress corrosion cracking under the union action of stress and environment medium; the reason was stress relief annealing was not done to the air valve after cold working deformation.