The pattern of fracture by impact penetration test and tensile fatigue test of thermite welding with stereoscan was observed,and the component of defect with energy spectrum was analyed.

观缺陷主要包括孔和夹,其中孔孔和缩孔组成,夹物按形态和尺寸分团簇夹、锥夹、粒夹、积聚物夹、夹和混合形夹。