Abstract
To estimate the formability in pipes of ferritic stainless steels, bulge test was conducted to the pipes. As the test results, the pipes were fractured at the weld metals, despite the hardness in weld metals is higher than other parts. From the calculated results by the thermal elastic-plastic analysis using mechanical properties in weld metals, HAZ and base metals, plastic strain has been concentrated at the weld metal in pipes during the forming process. Thus it seems to be concluded that the cause of experimental results described above is clarified by the calculated results.
