某风机盘管排气阀仅使用3个月便发生开裂,通过对开裂的排气阀进行宏观分析、断口及能谱分析和金相检验,对排气阀开裂原因进行了分析.结果表明:排气阀开裂起源于内壁,由于内壁接触了富含硫和氯的腐蚀性介质,加之排气阀在安装时受到了较大的外力作用产生了较大内应力,两者共同作用使排气阀内壁萌生应力腐蚀裂纹,裂纹不断扩展最终穿透壁厚导致开裂.

A fan coil exhaust valve cracked only used for 3 months,and the cracking reasons were analyzed by means of macro examination,fracture analysis,energy spectrum analysis and metallographic examination.The results show that the cracking of the exhaust valve originated from the inner wall.Because the inner wall touched the medium containing high content elements of Cl and S and there was large internal stress induced by the installation force,stress corrosion cracks formed under the co-action of above two factors.The cracks propagated continuously until penetrating the whole wall thickness and resulting in cracking.