| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing rolled wide flange shape which has a low yield ratio and excellent roughness. SOLUTION: A slab having a composition containing, by mass, 0.08 to 0.20% C, <=0.6% Si, 0.5 to 1.6% Mn, 0.01 to 0.05% Al, <=0.02% P, <=0.02% S, <=0.008% N and <=0.0004% H, and, if required, containing one or more kinds selected from Cu, Cr, Ni, Mo, Nb, V and Ti, and also satisfying Ceq(=C+Mn/6+Si/24+ Ni/40+Cr/5+Mo/4+V/14)<=0.38 is heated at 1,050 to 1,300 deg.C. After that, the slab is subjected to hot rolling so that rolling finishing temperature is controlled to the Ar3 point or lower to Ar3-60 deg.C or higher, and is immediately subjected to accelerated cooling to 500 to 250 deg.C at a cooling rate of 5 to 30 deg.C/sec.
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