某高速铁路固定式闪光焊接头伤损原因检验分析

Inspection and analysis of the reasons for the damaged fixed flash welding joint in a high-speed railway

通过对伤损固定式闪光焊接头超声波探伤,确定了焊接接头轨头缺陷的大小及分布,使用WAW-Y500微机控制电液伺服万能试验机将焊接接头压断,对断口进行了宏观形貌观察、扫描电镜微观分析、金相组织检验,并对焊接接头两侧钢轨母材的化学成分、拉伸性能、显微组织、非金属夹杂物这几项理化性能进行了检验。结果表明:固定式闪光焊接头母材性能满足技术要求,轨头内部熔合线处存在灰斑夹杂缺陷,在轮轨接触应力下已疲劳扩展,形成了轨头内部核伤。

Through ultrasonic testing of the damaged fixed flash welded to determine the size and distribution of the welded joint rail head defect. The damaged welded joint is broken by WAW-Y500 computer control electro-hydraulic servo universal testing machine. The fracture was examined by macroscopic morphology observation, SEM microscopic analysis and metallographic examination. The chemical composition, tensile properties, microstructure and nonmetallic inclusion of the weld the base material of the joint were tested. The results show that gray spot and impurities was found at the bond line in welded joint. Under the contact stress of wheel and rail, the inner nuclear damage of rail head was formed. The performance of base material meets the technical requirements.