采用金相试验手段研究了在不同焊接方法下同种奥氏体不锈钢管母材及焊缝的显微组织特性, 以及在相同焊接方法下奥氏体钢管和碳钢钢管母材及焊缝的显微组织特性。用超声检测方法对试样焊缝中的人工刻槽缺陷和边缘端角进行灵敏度和信噪比的定量检测, 研究了超声波在奥氏体不锈钢管和碳钢钢管中的传播特性差异。结果表明: 在两种不同的焊接方法下, 奥氏体不锈钢管母材及焊缝的显微组织状态基本相同, 对超声检测的影响差异不大;在相同的焊接方法下, 304奥氏体不锈钢管和20碳钢钢管的焊缝显微组织明显不同, 超声波在奥氏体不锈钢管焊缝内的传播效果较差, 检测存在一定困难;临界纵波双晶探头的灵敏度和信噪比均很高, 在检测表面缺陷时能获得较好的效果。

Microstructure characteristics of parent metal and weld metal of austenitic stainless steel pipe in different welding process were studied using metallographic test. And microstructure characteristics of parent metal and weld metal of austenitic stainless steel pipe and carbon steel pipe with the same welding process were also studied. Detecting sensibility and signal noise ratio both from artificial groove defect of weld and edge were quantitatively tested with ultrasonic method. The propagation property differences of ultrasonic wave were analyzed by comparing the data tested from austenitic stainless steel pipe and carbon steel pipe. The results showed that, by the two different welding methods, the microstructure of parent metal and weld metal of austenitic stainless steel pipe was same, and the effect difference on ultrasonic testing was not obvious. By the same welding method, the weld microstructure of 304 austenitic stainless steel pipe and 20 carbon steel pipe was markedly different, and the communication effect of ultrasound in austenitic stainless steel pipe weld was not good, which led to test difficultly. Because both detecting sensibility and signal noise ratio of critical longitudinal wave twin probe were very high, so the satisfactory effect to find the surface defects could be obtained.