| 摘要 |
PURPOSE:To improve the quality, yield and productivity as well as to reduce the tube bend and to shorten widely the adjusting time for straightening by arranging the specified number of the rolls of the downstream step among the drawing rolls to perform the drawing stage so as to give a strain in advance to the butt welded tube. CONSTITUTION:A butt welded tube making machine 10 is composed of forming roll 11, butt welding roll 12 and drawing rolls 13-24. The necessary number of the drawing rolls 22, 23, 24 of the roll stand of the downstream step in a drawing stage are set up with deviating in proper quantity in the horizontal or vertical direction against the rolling pass line to given in advance the reverse strain to the bending direction to the butt welded tube. The optimal direction and quantity to cause no bending on the butt welded tube are set up with respect to the eccentric direction and quantity. The reduction in bends and remarkable shortening in the adjustment times for straightening as well as the improvement in the yield and productivity are enabled.
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