| 摘要 |
PROBLEM TO BE SOLVED: To provide the method and device for manufacturing a seamless steel tube made of an Fe-base alloy whose Cr content is <15 wt.%, which are immediately applicable to existing manufacturing equipment by which a product steel tube reduced in spock marks due to the partial peeling of oxidized scale and indentation caused remarkably in the case the temp. on the outlet side of a sizing/finishing mill is over 900 deg.C in the steel tube, excellent in the surface properties and good in outward appearance is obtained. SOLUTION: By arranging high-pressure water type descalers 6a, 6b in the end part of a transporting route provided continuing to the outlet table of the sizing/finishing mill such as a sizer 2 and stretch reducer and, after executing outside descaling process to the steel tube just after sizing/finish rolling, by feeding the steel tube to a cooling bed 3 and on-line heat treating device 4, the thickness of oxidized scale on the outside surface of the steel tube at the point of time when the steel tube reaches the inlet side of a rotary straightener 5 is adjusted to <=50μm and rolling for straightening bend is executed under this state.
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