| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of not sufficiently improving buckling resistance property of an electric resistance welded tube by conventional technology. SOLUTION: In the manufacturing method of the electric resistance welded tube, a steel strip is roll formed while it is being passed, both abutted ends of the strip in a width direction are electric-resistance-welded to form a tube 10, heat treatment is applied to an electric resistance welded area, and then the tube is straightened. When straightening the tube, a rotary straightening machine 8 is used wherein the interval of the roll groove bottoms of at least one set of upper and lower rolls of the rotary straightening machine is made to be less than a tube outer diameter. COPYRIGHT: (C)2010,JPO&INPIT
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