SUS304奥氏体不锈钢板点焊接头的超声成像分析

Ultrasonic imaging analyses of spot welds on SUS304 austenitic stainless steel

利用超声波水浸聚焦入射法对1 mm厚的SUS304奥氏体不锈钢板点焊接头进行超声C扫描成像检测.分析了不同焊接工艺参数下的C扫描图像特征,甄别了飞溅、焊穿等典型焊接缺陷,并提取其对应的A扫描信号.基于C扫描图像对焊核直径进行了测量,并与焊核切口端面尺寸进行了比较.结果表明,基于超声波水浸聚焦入射法得到的C扫描图像,能有效观测焊核内部形貌特征.焊接电流超过8 k A,电极力小于2 700 N时,超声波C扫描图像中清晰反映出飞溅、焊穿等缺陷,其对应区域的A扫描信号与正常熔核区波形特征有明显差异;借助超声C扫描图像测得的焊核直径为4.39~5.25 mm.

The quality of spot welds in 1 mm SUS304 austenitic stainless steel sheet metal was evaluated by using ultrasonic water immersion focusing method. Splash,solder to wear and other weld defects were distinguished through the A-scan signals and ultrasonic C-scan images. Results showed that the Ascan signals in defective regions was obviously different from the waveform in normal nugget regions,C-scan image can get effective information from the inner pattern of the spot weld based on ultrasonic water immersion focusing method. When the welding current exceeded 8 kA and the supply electrode was less than2 700 N,it can get the information which included splash,solder to wear and other weld defects from the ultrasonic C-scan image. The measured diameter of spot weld ranged from 4. 39 mm to 5. 25 mm based on the ultrasonic C-scan image.