| 摘要 |
<p>PURPOSE: To prevent thickness variation in the longitudinal direction of a shell and to improve the precision of thickness in rolling with a restrained mandrel mill. CONSTITUTION: A speedometer 8 is provided between a mandrel mill 1 and a sizing mill 2 and the vm/vs of a shell speed vm on the outlet side of the mandrel mill 1 to the shell speed vs on the inlet side of the sizing mill 2 is controlled (1) when Rd<10%, in the range of 1.02<vm/vs<=1.05, (2) when Rd>=10%, in the range of 1.005<=vm/vs<=1.02. Where, Rd is the draft of the outside diameter (%), Rd(%)=((the outside diameter on the outlet side of the mandrel mill)-(the outside diameter of the shell on the outlet side of the sizing mill))/(the outside diameter of the shell on the outlet side of the mandrel mill)×100. In this way, the need of large equipment investment is eliminated, the thickness variation in the longitudinal direction of the shell is prevented, the precision of thickness is improved and the effect of the improvement of yield is increased.</p> |
