| 摘要 |
PROBLEM TO BE SOLVED: To provide a welded joint exhibiting excellent fatigue strength characteristics and economically applicable regardless of the kind of steel without applying any treatment after welding. SOLUTION: A weld bead shape of the welded joint is regulated in the ranges of weld bead width/steel material thickness (w/t) of≤0.2 and weld bead height/steel material thickness (h/t) of≤0.3. Further, the surface roughness of the front and the back surfaces of the steel material near the edge part of the weld bead is made to be≤6.3μm Ra and/or the ratio of the yield strength of the welded metal to the yield strength of the steel material is desirably made to be≤1.3. Furthermore, the steel material is desirable of a specific composition and bainite single phase structure. COPYRIGHT: (C)2004,JPO&NCIPI
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