液压作动筒裂纹分析

Analysis on Cracks of Hydraulic Cylinder

某型发动机液压作动筒在打压和试车阶段发现泄漏,检查发现焊缝处存在裂纹。利用微距照相机和扫描电镜对液压作动筒裂纹外观、裂纹断口进行宏微观观察,并用能谱仪进行成分分析,利用金相显微镜和显微硬度计对作动筒进行了组织与硬度检测。结果表明:液压作动筒受到应力腐蚀作用,在打压试验或试车前期就萌生裂纹,造成早期失效;建议严格控制焊缝背面余高和尖角过渡,同时从作动筒清洗等工序查找腐蚀介质来源并加以控制。

Three hydraulic cylinders leaked fuel oil during pressing and aeroengine test,Cracks were found in the welding of the hydraulic cylinders.In order to find out the failure mode and cause,macro and micro observation on crack surface,fracture surface,energy spectrum analysis,microstructure examination and hardness testing were carried out.The results show that the crack initiated due to stress corrosion,resulting early failure.Controling the weld reinforcement and weld toe size,then finding the origin of corrosion medium to control it.