| 摘要 |
PROBLEM TO BE SOLVED: To form a welded joint having excellent brittle fracture generation resisting properties (fracture toughness value Kc) in high heat input butt-welding for a high strength thick steel plate, and to verify the properties. SOLUTION: In the welded joint, (a1) the ratio between the hardness Hv(WM) of a weld metal and the hardness Hv(BM) of a base material, Hv(WM)/Hv(BM) is <1.1, or (a2) the hardness Hv(WM) of the weld metal is≤210, and also, the fracture toughness value Kc of the weld zone satisfies (b1) >2,000 N/mm<SP>1.5</SP>or (b2) Kc≥Kq(=σ<SB>D</SB>√(πa),σ<SB>D</SB>: design stress, and a: assumed defective dimensions). Its brittle fracture generation resisting properties (fracture toughness value Kc) are verified by confirming the facts that actual hardness value satisfies the above (a1) or (a2) and actual absorbed energy vE satisfies requirement vE and using predicted Kc value based on transition temperature vTrs. COPYRIGHT: (C)2006,JPO&NCIPI |
