| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cold-rolled steel sheet for AT (automatic transmission) plate which has wear resistance and blanking workability equal to or better than those of the conventional material and reduces the residual stress which causes the deformation due to heat strain when the blanked material is heated and held at that temperature. SOLUTION: A slab having a composition, by wt%, of 0.15 to 0.25% C,≤0.25% Si, 0.3 to 0.9% Mn,≤0.03% P,≤0.015% S, 0.01 to 0.08% Al,≤0.008% N, 0.01 to 0.05% Ti, 0.002 to 0.005% B and the balance substantially Fe is hot-rolled at a hot-rolling finish temperature equal to or higher than the A<SB>3</SB>transformation point, and 500 to 600°C coiling temperature. After pickling the hot-rolled steel sheet, cold-rolling is applied at a draft of≥50% without annealing. Thereafter, the residual stress developed at the cold-rolling is eliminated by using a roll having≥300 mm diameter and applying a light draft rolling of≤1%. COPYRIGHT: (C)2005,JPO&NCIPI
|
