30CrMnSiNi2A钢活塞杆断裂分析

Fracture analysis of 30CrMnSiNi2A steel piston rod

30CrMnSiNi2A钢活塞杆在试验过程中易发生提前断裂。对断裂活塞杆进行了外观检查,金相组织、洛氏硬度和冲击性能检测,对活塞杆故障及人为打断断口进行了宏观微观检查、能谱分析,综合分析了活塞杆断裂的性质和原因。结果表明,活塞杆的断裂性质为过载断裂,断口形貌主要为沿晶及韧窝特征,局部呈熔融晶界特征;断裂原因为活塞杆热处理过程中加热温度过高引起过烧,导致活塞杆脆性增大,在试验过程中受到冲击载荷的作用发生提前过载断裂。改进措施为加强热处理工艺控制和组织检验。

The 30CrMnSiNi2A steel piston rod is prone to premature fractured during the test.The failure mode and cause were analyzed by appearance observation,metallographic examination,tests of hardness and impact property of the piston rod,as well as macro-and-micro observation of the fracture surface and energy spectrum analysis(EDS).The results showed that the failure mechanism of the piston rod was overload fracture with the morphologies of intergranular fracture,dimple and melting of partial grain boundary.The fracture was caused by overburning caused by higher heating temperature which increase the brittleness and overload fracture during test.Improvement measures were proposed that heat treatment process and metallographic examination should be reinforced in order to avoid fracture induced by overburning.