| 摘要 |
PURPOSE:To remove a projecting seam effectively by blowing oxygen and steam of prescribed pressure in different two places from the beginning end position for forge welding where a heated skelp is forge welded to a pipe shape along the advance direction of the pipe onto the surface in the forge welded part on the inner side of the pipe apart by a prescribed distance from said position. CONSTITUTION:A heated skelp 1 fed at a pipe making speed Vm/min is formed to an approximately round shape with forming rolls 2 and is forge welded with forge welding rolls 4. Oxygen of 0.047V<1.052P00.1648V<0.912> gage pressure P0Kg/ cm<2> is blown from a nozzle 5 from the beginning end position A of said forge welding to the position B on the forge welded surface on the inner side of the pipe apart by 20-350mm. therefrom in the advance direction of the pipe, whereby a projecting seam is heated. Thereafter, steam of Ps>7 gage pressure Pskg/cm<2> is blown from a nozzle 6 to the position on the forge welded surface in the pipe apart by 20-250mm. from the position B along the advance direction of the pipe, whereby scarfed slag is blown off. |
