| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fillet welded joint superior in fatigue characteristics with a fillet joint of an extremely thick steel plate of 50 mm or thicker of sheet thickness. <P>SOLUTION: The fillet joint of the thick steel sheet superior in fatigue resistant characteristics of a sheet thickness direction of 50 mm or larger of the sheet thickness is welded with 30 kJ/cm or less of input heat and 3 layers and 6 passes or less of a laminate. In a range from a position of 2 mm in the sheet thickness direction from at least both sides of a rolled face of the steel sheet or one side thereof up to a position of 3/10 of the sheet thickness, the thick steel sheet has an aggregate structure in which an X-ray intensity ratio of a face (110) parallel to a plate face is 2.0 or more, and an X-ray intensity ratio of a face (100) parallel to the sheet surface is 1.1 or less. Furthermore, an average value of residual compressive stress in the sheet thickness direction is 160 MPa or more or residual compressive stress in the sheet thickness direction and an orthogonal direction is 100 MPa or more in a range up to 4 mm in the sheet thickness direction from both side or one side of the rolled face of the steel sheet. <P>COPYRIGHT: (C)2013,JPO&INPIT |
