新制御圧延型50キロ級高張力鋼板の破壊靱性とその評価

概要

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The authors investigate the main strength characteristics of the 50kgf/mm^2 class newly developed controlled rolling steel plates especially for the welded joint made by high heat-input welding and also evaluate the fracture toughness of these plates, when they are used for ship's hull. And also investigate the crack arresting properties of the newly developed controlled rolling steel plates. That is, this report shows the fracture toughness of Z direction (at the middle of plate thickness) and of the welded joint by high heat-input welding, and also proposes a method of estimating the values of fracture toughness of welded joint from V-notch Charpy absorbed energy. When these plates are used as the material of ship's hull, it is possible to adopt the welding method of the highest class heat-input welding that has been used in the building stage of Shipbuilding yard. And after comparing K_<Cα> characteristic between these plates and conventional process steel plates (Normalized or Quenched and Tempered), a possibility of using these newly developed controlled rolling steel plates as "crack arrester" for brittle fracture is discussed, supposing that necessary K_<C> value for "crack arrester" should be greater than 600kgf<mm>/mm^2 (K_6lt;C>>__=600 kgf<mm>/mm^2 ) .
社団法人日本船舶海洋工学会の論文