| 摘要 |
PROBLEM TO BE SOLVED: To provide high strength wide flange steel of a class of TS 500 to 700 MPa having excellent fillet part toughness, and to provide a production method for inexpensively and efficiently producing the same. SOLUTION: This rolled wide flange shape is produced by heating the continuously cast slab stock of Si deoxidized steel having a composition containing <=0.05% C, <=1.0% Si, 0.6 to 2.0% Mn, 0.010 to 0.10% Nb, 0.005 to 0.030% Ti, 0.003 to 0.006% B and 0.005 to 0.010% N at 1,200 to 1,350 deg.C, threafter subjecting the same to breakdown rolling, next subjecting the rolled stock to rough universal rolling under the conditions in which rolling finishing temperature is >=800 deg.C, and the cumulative draft at the rolling temperature of <=950 deg.C is <50% and then performing finish universal rolling. |
