液压挖掘机用高压软管接头开裂原因

Cause of Cracking on High-pressure Hose Tube Fitting for Hydraulic Excavator

某液压挖掘机用高压软管接头在使用过程中开裂。通过断口分析、化学成分分析、金相检验、硬度测试和再现试验等方法对高压软管接头的开裂原因进行了分析。结果表明:开裂软管接头在进行加热弯管加工时,突遇急冷导致显微组织中出现马氏体,且后序电镀工序无去氢工艺,增加了软管接头的氢脆敏感性。最终在工作应力的作用下,软管接头发生了氢致延迟开裂。

The high-pressure hose tube fitting of a hydraulic excavator cracked in use.The causes of cracking of high-pressure hose tube fitting were analyzed by means of fracture analysis,chemical composition analysis,metallographic examination,hardness test and reproduction test.The results show that the martensite appeared in microstructure of the cracked hose tube fitting due to sudden cooling during the processing of heating bend tube,and the hydrogen embrittlement sensitivity of hose tube fitting increased because of the subsequent electroplating without dehydrogenation process.Finally,hydrogen induced delayed crack of the hose tube fitting occured under the action of working stress.