| 摘要 |
PURPOSE:To prevent surface roughening during working and to improve the ductility by coiling a hot rolled steel material contg. prescribed percentages of C, Mn, Al, N, Sb and Ge at a prescribed temp. and by carrying out continuous annealing at a prescribed temp. CONSTITUTION:A steel slab contg., by weight, 0.008-0.035% C, <=0.3% Mn, 0.005-0.035% Al, <=0.003% N and 0.003-0.02% Sb and/or Ge is hot rolled. The hot rolled material is coiled at <650 deg.C, cold rolled, and treated at 750-880 deg.C soaking temp. by a continuous annealing method. By this method, surface roughening during working due to the abnormal growth of grains is prevented, and the ductility is improved. |
