Recent Ship Steels and Some Considerations in Their Welding-TMCP Steel-

The volume of ships built with high tensile steel (HT steel) at various shipyards has been on the steep increase these days. Among HT steels, the consumption of TMCP steel (TM type HT) is particularly significant. The reasons behind such a sharp increase in the use of TMCP steel may be identified in that the steel of this type can be manufactured with less consumptions of energy and natural resources and that it promises an added advantage of better welding results by the improved material characteristics. Reflecting the above, the use of this steel has been extending from major shipyards to medium-size yards in Japan. Here, the outlines of the manufacturing process of TMCP steel, its material characteristics including those at welded joints, and its welding workmanship conditions will be explained with necessary notes also on the current and future trends of the rules and regulations of the Classification Societies in relation to the steel specifications and application standards to ship structures and others. This paper represents the current information in addition to the text entitled "The New Shipbuilding Technology" made public at the 11th Summer Symposium sponsored by the Society of Naval Architects of Japan held in September 1985.