| 摘要 |
PURPOSE:To manafacture an electric welded pipe of high quality by performing the dry forming of a beltlike plate into a tubular shape by forming rolls including a soft material roll, and press-welding edge parts by heating after spraying high-pressure gas. CONSTITUTION:A beltlike skelp 1 unwound from an uncoiler 9 is curved cylindrically by forming rolls 10 in a forming stage 6. In this case, some or all of the rolls 10 are soft-material ones. After the stage 6, the skelp 1 is heated in a welding stage 7 for pressure welding. In this case, high-pressure gas is spouted from a jet nozzle gruop 11 to completely removing sticking foreign matter from the skelp edges 3 of the tubular skelp 1, which is then heated by a work coil 2 and welded under pressure by a squeezing roll 4. In a trailing sizing stage 8, the skelp 1 welded in the stage 7 is sized to a desired external diameter and roundness. |
