采用化学成分分析、力学性能测试、扫描电镜和电子能谱仪等方法,分析了某载重车辆30CrMnSiA螺栓断裂的原因.结果表明:螺栓失效是由氢引起的延迟脆性断裂;认为机械渗锌零件并不能完全排除发生氢脆的可能性,当材料的本质氢含量较高而又具有极高的抗拉强度时,由于缺少除氢环节,采用机械渗锌工艺反而使得机械零件产生氢脆的可能性更高.

By means of chemical composition analysis,mechanical property testing,scanning electron microscopy (SEM) and electron diffraction spectrometer(EDS) etc.,the fracture reason of some 30CrMnSiA bolts used for load-carrying vehicle was analyzed.The results show that the fracture of the bolts was delayed brittle failure induced by hydrogen.It was proposed that mechanical zinc plating could not completely avoid hydrogen embrittlement.When the material is with had high inbeing hydrogen content and high tensile strength,the risking of hydrogen embrittlement is high if the machine part was made by mechanical zinc plating because of lack of the process to remove hydrogen.