| 摘要 |
PURPOSE:To control rolling behavior correctly by hot rolling a steel slab containing <=0.3wt% and alloy elements adjusted in composition according to the purpose controlling the rolling by calculated average temperature through the thickness by using the thickness of material and career of rolling to become to that thickness as factors. CONSTITUTION:A steel slab containing <=0.3wt% C and alloy elements adjusted in composition according to the purpose is soaked to above 900 deg.C and hot-rolled. At this time, the change of temperature during the rolling process of the steel slab is grasped in the average temperature through the thickness Tm. In calculating temperature by heat transmission based upon rolling data to the steel slab, actual temperature of transformation is estimated by deviation of actually measured temperature from temperature calculated by extrapolation making the values of propperty of material in the austenite domain as data after equilibrium transformation. Then, rolling pattern is so made that the pass holding time from immediately before Tm reaches Ar3' to starting of pass is within 15 seconds, and the total rolling reduction (r) from a temperature higher than Ar3' by 100 deg.C to Ar3 becomes 10% or more. |
