起落架30CrMnSiNi2A钢斜支柱裂纹分析

Crack Analysis on Raking Strut on Landing Gear Made of 30CrMnSiNi2A Steel

某型飞机服役一段时间后发现右主起落架斜支柱漆层表面有一条细纹,去除漆层后经着色、涡流检查,显示存在长约30 mm的裂纹。为确定裂纹产生的原因,分别对开裂斜支柱进行了外观检查、宏观和微观观察、能谱分析及残余应力、金相组织、硬度、氢含量、氢脆敏感性测试与研究。结果表明:斜支柱裂纹为沿晶穿透性裂纹,形态符合应力腐蚀裂纹的特点,斜支柱的开裂应该与特殊的高腐蚀使用环境有关。建议优化热处理工艺,降低斜支柱的抗拉强度,增加表面处理层,提高抗腐蚀能力。

After a certain aircraft has been in service for a period of time,it was found that there was a fine crack on the surface of the painting of raking strut of the right main landing gear.After removing the painting layer,it was shown by coloring and eddy current inspection that there was a crack of about 30 mm in length.In order to determine the cause of crack,the cracked raking strut was tested and analyzed by appearance inspection,the macro-observation and micro-observation,energy spectrum analysis,residual stress,metallographic structure,hardness,hydrogen content and hydrogen embrittlement sensitivity.The results showed that the crack of raking strut was intergranular penetrating crack,which conformed to the characteristics of stress corrosion crack,and the crack of raking strut should be related to the special high corrosion service environment.It was suggested to improve the heat treatment process to reduce the tensile strength of raking strut and increase the surface treatment layer to improve the corrosion resistance.