38CrMoAlA挤出机螺杆轴断裂失效分析

Fracture Failure Analysis of 38CrMoAlA Extruder Screw Shaft

采用断口宏微观形貌、金相检验、力学性能、化学成分分析和有限元模拟等方法对挤出机螺杆轴失效原因进行了分析。结果表明:表面划痕、夹杂物偏析、金相组织缺陷等原因导致材料的抗冲击性能下降,从而使多个疲劳源在应力集中和交变载荷的作用下加速扩展,最终发生疲劳断裂失效。

The failure causes of 38CrMoAIA extruder screw shaft were investigated by macro and micro morphology, metallographic, mechanical test, chemical composition analysis, finite element analysis and other methods. The results show that the surface scratches, inclusions segregation and the defects of metaltographic microstructure contribute to the decrease of the shock resistance properties of the material, which can accelerate the propagation of the multiple fatigue source under stress concentration and alternating load, eventually leading to the fatigue fracture failure.