Static and fatigue properties of 80 mm-thick Q460GJC butt weld joint

Abstract

Chinese domestic steel plate for building structure, i.e. GJ steel, has been widely used in many major projects due to its comprehensive high performance. This study aims to investigate the static and fatigue properties of butt weld joints of Q460GJC steel plate with a thickness of 80 mm, and to obtain the variation of properties along different layers in the weld zone and heat-affected zone. Test pieces were sampled from the weld zone and heat-affected zone of a box section member welded by 80 mm Q460GJC steel plate, and static and fatigue tests were carried out subsequently. The static and fatigue properties of different layers of the weld zone and the heat-affected zone were compared. Further, fatigue calculation formulas were proposed according to the European code, the US specification and the Chinese code. The result indicates the lower layer (the inner surface of the box section) and the mid-layer of the weld zone show higher yield point than the upper layer (outer surface of the box section), while the yield point of the upper layer and the lower layer of the heat-affected zone is higher than that of the mid-layer. And the mid-layer of the weld presents higher fatigue strength than the upper layer. Moreover, the tested fatigue strength of the mid-layer and the upper layer of the weld is higher than the corresponding values that calculate according to the European code, the US specification and the Chinese code.