Development of a method to evaluate strain in weld solidification using in-situ observations with high-brightness synchrotron X-rays

Welding is a crucial joining technique used in various industrial fields. Recently, we developed an in-situ observation technique using high-brightness synchrotron X-rays to observe the formation of weld solidification microstructures. This study proposes a new method to evaluate the strain distribution and strain history of weld solidification zones using time-series in-situ images. The in-situ images were obtained using the beamline at SPring-8, and we employed an Fe-15Mn-10Cr-8Ni-4Si alloy (in mass%) developed for seismic dampers that is prone to solidification cracking during welding. The strain distribution obtained using the proposed method is compared with that calculated using the template matching method, and its effectiveness is verified. The obtained strain distribution corresponds to known findings, showing a consistent distribution regardless of the resolution of the in-situ images. The proposed method is useful for detailed strain evaluations in weld solidification zones and is expected to become a new tool for future research aimed at understanding solidification cracking, residual stress, and residual deformation in welding technologies. A method was developed to evaluate strain distribution and history in weld solidification using synchrotron X-rays. This method is expected to become a new tool for understanding welding phenomena.