Brittle Crack Propagation Path Due to the Effect of Welding Residual Stresses

Recently, the size of the ship required to explore and produce oil and natural gas in the arctic offshore region has greatly increased the demand for large vessels. In the shipbuilding industry, the container ship size has gradually increased for mass transportation and cost reduction in the shipping industry. Thus, thick and high-strength steel plates are used for the upper deck structure of container ships because of their large hatch openings. As the increase of plate thickness, the fracture toughness decreases in it. Therefore, it is important to evaluate of the fracture toughness in thick steel plate. In order to evaluate the brittle crack propagation arrest toughness, generally large scale test carried out with full thickness despite the difficult of the experiment. In this study, to clarify the brittle crack propagation arrest mechanism in welds and to establish the basic theory of the technique to avoid brittle fracture, the brittle crack propagation mechanism was investigated using small scale specimens. Key words: C-T specimen, Brittle crack arrestability, Welding residual stress, Fracture toughness