Recently, there have been the increase of ship size and the development of oil and gas in arctic region. These trends have led to the requirements such as high strength, good toughness at low temperature and good weldability. The evaluation of the brittle crack arrest toughness value (Kca) and the development of the brittle crack arrest method for the welded joint of shipbuilding steel plate were experimentally conducted. To evaluate of brittle crack propagation path, measurement of welding residual stress in both welded joint. In this study, it was aimed to investigate the effect of welding variables on the crack arrest toughness and crack propagation path of thick steel plate welds. Quantitative analysis by temperature gradient ESSO test was conducted to clarify the effect of welding variables for flux cored arc welding (FCAW) and electro gas welding (EGW) joint of thick steel plates with the thickness of 50 and 80mm. Also, welding residual stress was measured for evaluate of welding residual stress effect in both welding process in brittle crack propagation path using neutron science analysis.
Recently, as the containerships have been larger and larger above 13,000 TEU for the economical transportation, there has been much demand for the stronger and thicker steel plate in shipbuilding industries. They started introducing EH40 or higher grade steel with a thickness of 80~100mm into the construction of real ship structures. As the containership became larger, fracture toughness of the steel plate got to be an important factor for the integrity of ship structures. The size of container ship has been gradually increased for mass transportation and cost reduction in the shipping industry (Hsu, 2005). Thus, thick and high strength steel plates are used for the upper deck structure of container ship because of its large hatch openings (Yamaguchi, 2006).
