空调器用电子膨胀阀外壳应力腐蚀裂漏分析

Analysis on stress corrosion crack and leakage in shell of electronic expansion valve for air conditioner

针对空调器售后出现电子膨胀阀不锈钢外壳裂漏问题,通过对故障件进行壳体化学成分、机械性能、裂漏点截面显微组织、裂纹区域化学成分、生产工艺等方面分析,确认裂漏原因是电子膨胀阀外壳存在冷加工与焊接应力及外部水分侵入内部带来Cl-而产生的应力腐蚀开裂。开展电子膨胀阀外壳去应力和使用过程防进水的整改,未再发生此类故障。

In the after-sale of air conditioners,the crack and leakage happens for some stainless steel shells of electronic expansion valve.The the faulty parts are analyzed at the aspects of chemical composition and mechanical properties of shell,section microstructural of leak points,chemical composition of crack and leakage region and manufactory＇s production process,and it＇s determined that the reason of crack and leakage is stress corrosion crack caused by the stress of cold working welding and the Cl-carried by the outside water.The rectification on the electronic expansion valve is conducted focusing on the stress removal on the shell and waterproofing during the using,thus no such fault occurres again.