抄録
It is needed to obtain the fracture toughness of butt-welded joints of heavy thick steel plates accurately to ensure strength and reliability of upper structure of very large container ships using heavy thick steel plate with 50 to 100mm thickness.
In our previous study, the tensile test by using the center notched small size tension test specimen had been proposed to obtain the fracture toughness KIC for unstable brittle fracture initiated at the tip of a fatigue crack which generates on the surface of butt-welded joint of heavy thick high-tensile strength steel plates then propagates from there.
In this study, the fracture toughness KIC values of butt-welded joints of heavy thick high-tensile strength steel plates (YP36, YP40, YP47) for ship building by the center notched small size tension tests were evaluated. As the results, by using the center notched small size tension test specimen, valid fracture toughness KIC can be obtained and by adding the effect of the weld residual stress the fracture toughness KIC values of the welded joints by the center notched small size tension tests show good agreement to them by the center notched wide plate tension tests.
