Method for Control of Dimensions of Round-to-shaped Tube

In general there are four key elements closely related to adjustment and control of dimensions of the round-to-shaped tube，namely the basic dimensions，the diagonals，Angle r and the squareness of the tube.Using the basic principle for controlling the dimensions of the said tube，and relevant operational experiences，the method for adjusting the tube dimensions，and measures for adjusting Angle r of the tube are worked out in case of r<1.5t and r>1.5t.Addressing the problems that the diagonals of the tube are unequal to each other，and the tube squareness is poor，based on the different deviations，corrections can be made by means of setting the vertical roll gap or the horizontal roll gap.As for the adjustment of the tube basic dimensions，it can be done with the procedures as first，making the measurements pass by pass as per the process requirement，then，roughly adjusting A_i≈a_i and B_i≈b_i，and finally precisely adjusting the vertical roll and the horizontal roll of the last pass（or Pass i-1）.