MANUFACTURING METHOD FOR STEEL TUBE, SEAM PART INNER FACE BINDING APPARATUS FOR STEEL TUBE AND SEAM INNER FACE SMOOTHING APPARATUS FOR STEEL TUBE

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method for a steel tube, a seam part inner face binding apparatus for a steel tube and a seam part smoothing apparatus for a steel tube capable of preventing generation of a weld line. SOLUTION: A seam part inner face binding apparatus has a jig holding carrier arranged in a steel tube and an inner face binding jig held to the jig holding carrier and to bind a seam part inner face. The inner face binding jig is arranged so as to abut on the seam part inner face between the position where both edge parts of open tubes are abutted and the position right under squeeze rolls. The inner face binding jig is preferably of a roll or a shoe. A seam part inner face rolling apparatus has a roll holding carrier for inner face rolling, a roll for inner face rolling to roll an inner face bead and a guide roll opposing to the roll for inner face rolling. In a solid phase pressure joining steel tube manufacturing line, the seam part inner face binding apparatus and the seam part inner face rolling apparatus are successively arranged, by binding the seam part inner face and conducting inner face bead rolling, the seam part is made to a smooth steel tube.