| 摘要 |
<P>PROBLEM TO BE SOLVED: To form a weld joint having a sufficiently high fracture toughness value δc by butt-welding a high-strength steel sheet for electron beam welding, which has yield strength of ≥355 MPa class and has a sheet thickness of >50 mm. <P>SOLUTION: The electron beam weld joint with excellent resistance to generation of brittle fracture is a butt-weld joint of a welded structure, which has the following characteristics: (a) the hardness of a weld metal part is ≥110 and ≤220% of that of a base material; and (d) the prior austenite grain size of a weld heat-affected zone (HAZ) which is in contact with a weld fusion line is ≤100 μm; if necessary, (b) the width of the weld metal part is ≤20% of the sheet thickness of the base material; and/or (c) the width of the region of the weld heat-affected zone, which is softened to hardness of ≤95% that of the base material not affected by heat, is ≥3 mm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
