大锻件超声波检测中草状波缺陷的形成原因

CAUSES OF GRASS WAVE DEFECTS IN ULTRASONIC TESTING OF LARGE FORGINGS

利用EBSD金相显微镜对正火后的HYRH12试样进行了组织观察,分析了超声波检测过程中草状波缺陷产生的原因。认为,HYRH12中的草状波缺陷是由粗晶产生的,粗大晶粒的边界可以成为超声波的反射体,进而产生草状波缺陷;二次正火处理后,草状波缺陷的合格率明显高于一次正火之后。研究结果证明,可以通过多次正火获得细小的晶粒从而消除草状波缺陷。

The microstructure of normalized HYRH12 sample was observed by EBSD metallographic microscope,and the causes of grass wave defects in ultrasonic testing were analyzed.It is considered that the grass wave defect in HYRH12 is produced by coarse grains,and the boundary of coarse grains can become a reflector of ultrasonic wave,resulting in grass wave defect;the qualified rate of grass wave defect after secondary normalizing is significantly higher than that after primary normalizing.The results show that fine grains can be obtained by multiple normalizing,so as to eliminate grass wave defects.