To accurately control the thickness of a steel strip after rolling in the high draft rolling of the hot rolled steel strip in which scale is mechanically descaled.
At the time of cold-rolling the hot rolled steel strip with the scale sticking at the draft of 30-50% and removing or peeling the scale from the surface of the hot rolled steel strip, the thickness on the outlet side of a rolling mill is corrected to the thickness after descaling and rolling conditions are controlled so that the thickness after descaling is fallen in the target range. The thickness on the outlet side of the rolling mill is corrected to the thickness after descaling according to the formula h=hout-hs. Where, (h) is the correction of thickness (mm), hout is the measured value of the thickness with mill scale on the outlet side of the rolling mill (mm), hin is the measured value of the thickness with mill scale on the inlet side of the rolling mill (mm), h. is the calculated value of the thickness of scale on the outlet side of the rolling mill (mm), hs=2(0.095.106.exp(-18677/1.987.X +0.56.105.exp(-18677/1.987.Y)+3.116×(h0/hin)×(1/1000)(mm), T is the actual coiling temp. in the hot rolling (°C), K is the correction factor by the component of the base stock.
KOBAYASHI MASAYUKI
MIKI TOSHINORI
