Welding-Metallurgical Evaluation for Residual Stress Measurement Accuracy of Multi-Pass Girth Welded Pipe Joint in Austenitic Stainless Steel by X-Ray Diffraction
Tadafumi HASHIMOTO, Shigetaka OKANO and Masahito MOCHIZUKI
Abstract: In welded pipe joints of austenitic stainless steel, the mismatch of residual stress distribution often occurs between a variety of measurement method and the numerical simulation. It is especially known that non-destructive measurement such as X-ray diffraction method makes remarkable different due to the microstructure evolution by the welding. Meanwhile, the multi-pass girth welded pipe joints of austenitic stainless steel in this work were consistent with the thermal-elastic-plastic analysis and the typical stress distribution due to the welding was obtained. This reason was clarified from the welding metallurgical evaluation. The material of FA (ferrite to austenite) mode solidification with K-S relationship has the random and fine structure, compared with other systems. Therefore, specific systems facilitate the X-ray stress measurement in the welded zone of austenitic stainless steel and the pure stress by the welding could evaluate. Key Words:Welding residual stress, Austenitic stainless steel, Multi-pass girth welded pipe joint, X-ray stress measurement, Thermal-elastic-plastic analysis, Welding metallurgy, ƒÂ/ƒÁ transformation