水力发电机导水机构偏心销断裂失效分析

Fracture Analysis of the Eccentric Pin on the Inlet Structure from a Hydraylic Generator

根据设计技术条件要求和材料力学性能标准规范,用金相检验、扫描电镜技术和EDX对偏心销断裂原因进行失效分析。结果表明,高温热锻时晶界发生局部过烧现象导致晶界弱化是断裂的主要原因;另外夹杂物等级偏高、淬火组织中存在网状铁素体和螺纹退刀槽圆弧过渡半径过小也是造成断裂的原因。

According to design parameters and mechanical properties, the fracture of the eccentric pin has been analyzed by metallographic microscope, SEM and EDX. The result shows that the main cause of the rupture is the weakened crystal boundary formed when forging in a high temperature i. e. partly over-burning; the high grade of the inclusions, the network of the primary ferrite in the quenching structure and the small transition radius of the screw thread slot are also the reasons for the rupture.