超声波检测法辨别焊缝中微细裂纹OA

An indiscernible defect reflection wave is found by ultrasonic testing method when detecting the weld seam of ocean engineering steel structure,the difficulty is that the wave pattern of this reflection wave is like a transverse crack,but the amplitude is very low,the transverse scan has reflected waves,the longitudinal scan sometimes does not have reflected waves,and the transverse scan amplitude is higher than the longitudinal scan.There are waves in the ultrasonic display,according to experience,this reflected wave should be a defect,and it should be a transverse crack,but the gouging and grinding to the designated position,and no defects are seen.In order to solve this problem,the ultrasonic testing method mainly uses GE USM35 ultrasonic flaw detector and 45°,60°and 70°probes for multi-direction scanning of this batch of welds.After one-to-one scale mapping,the horizontal position and vertical depth of the defect reflection wave are accurately located,and then the air gouging is carried out at a certain distance from the specified depth,the grinding and magnetic particle testing is gradually carried out.Finally,the transverse micro cracks and micro pores are found and verified,and the method of distinguishing the two defects is summarized.