TMCP型降伏点40kgf/mm^2級船体用高張力鋼板とその溶接・加工性

概要

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TMCP steels with a specified yield strength of 40kgf/mm^2 (YP40 steels) by accelerated cooling process are being used partially in the principal structural members of ships. Among HT steels, the yield strength is shifting from 36kgf/mm^2 to 40kgf/mm^2 in actual use. In this paper, the specified specifications of YP40 steels are introduced, and some considerations are given to the conditions of manufacturing process of steels and the various characteristics for their fabrications in shipbuilding. The study showed that for YP40 steels; (1) the satisfactory results for the strength and toughness are realized by controlling the chemical compositions, rolling conditions and cooling conditions in combination. (2) upper limits of Ceq. and P_<CM> are as follows. (a) Ceq.: about 0.38% (b) P_<CM>: about 0.22% (3) the following fabrication standards are proposed, but further investigations are to be made. (a) Preheating: Not necessary When Ceq.≦0.36% and Temp.>0℃ (b) Short bead: Min. 30mm in length When Ceq.≦0.38% (c) Line heating: Water cooling after heating When Ceq.≦0.38% (4) as hot forming causes lowering of the strength, special considerations for Ceq. and chemical composition are to be required
社団法人日本船舶海洋工学会の論文
1987-08-25