The fillet and are superior in brittle crack propagation halt property of the cruciform weld the thick thing steel sheet and its production

摘要

PROBLEM TO BE SOLVED: To provide a thick steel plate with a plate thickness of ≥50 mm having excellent brittle crack propagation stopping properties and suitable for the hull structure of a large vessel.;SOLUTION: Regarding the thick steel plate, in the region of ≥20% of the plate thickness in the plate thickness direction and also in the part other than the region within 10% of the plate thickness from the surface layer, brittle crack propagation stopping toughness Kca equivalent to the plate thickness of 25 mm in service temperature is ≥10,000 N/mm^3/2, and the part has a texture where the X-ray intensity ratio between the (211) face and the (100) face in the rolling face is ≥1.5, and the (211) face X-ray intensity ratio X₍₂₁₁₎ and the(100)face X-ray intensity ratio X₍₁₀₀₎ in the rolling face, and fracture appearance transition temperature vTrs(°C) obtained by a 2mmV notch Charpy impact test satisfy inequality; vTrs-12X₍₁₀₀₎-22X₍₂₁₁₎≤(T-75)/0.64; wherein T denotes the service temperature (°C) of the steel plate.;COPYRIGHT: (C)2008,JPO&INPIT