2018 年 84 巻 1 号 p. 103-109
Laser shrink fitting for pipe coupling was developed as an application of laser forming. The coupling of the pipe of stainless steel and bar of hardened oxygen-free copper is made by laser shrink fitting. A bar is inserted into a pipe, and the pipe surface of the bar-inserted-part is irradiated and heated by 1kw class laser. Metallographic structure of the laser irradiated part of the pipe is not changed. Metallographic structure of the bar is changed into recrystallization structure. The fitted part of the pipe is shrunk in both circumferential and axial direction. The residual stress on the surface of the fitted pipe is compressive in both circumferential and axial direction. The tensile strength of the fitted part is 53% to the tensile strength of base metal of hardened oxygen-free copper bar.