Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 13, 2020 - September 16, 2020
In order to investigate the effect of hydrogen on fracture mechanism of a carbon steel JIS-S25C in tensile tests, the metallurgical structure was observed by microscope and Electron Back Scattered Diffraction (EBSD) in terms of crystal deformation. Tensile tests were conducted using hydrogen charged and uncharged specimens introduced pre-strain (0%, 5% and 10%). The hydrogen content of the hydrogen charged specimens increased in increasing pre-strain, and the reduction of area decreased in increasing the hydrogen content. After tensile tests, the metallurgical structure of longitudinal cross section of tensile specimens near the fracture surface by microscope were observed. Many voids of hydrogen charged specimens were observed compared with uncharged. In order to reveal the mechanism of void initiation, crystal orientation of tensile specimens was observed by EBSD. The crystal orientation of the hydrogen charged specimens changed significantly in one crystal compared with the uncharged. The crystal orientation at any point obtained from EBSD maps was compared to that at the adjacent to the point.
