... joint under the force of squeeze roller.And it uses induction welding to heat the longitudinal seam.That is ,feed ... butt-welding → material accumulating → non-power leveling →mill-forming → high-frequency welding → removing burrs outside of weld seam → cooling → sizing → ... ,hydrostatic testing machine,charge table,sack&bale machine,high frequency DC drag,product line electric applicance. If you have ...