| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that the manufacturing cost of a seamless steel pipe is increased by the generation of damages such as the wear and burning and further breakage of a plug when the seamless steel pipe is rolled by using a plug mill. SOLUTION: A steel pipe rolling plug 21 which is provided with three rotating bodies 31 which are arranged in the inside of the steel pipe 50 while being brought into contact with the inside surface 50a of the steel pipe 50 and also has rotary shafts 29 in a direction approximately parallel to the working direction of the steel pipe 50 and, by rotating the steel pipe rolling plug 21 around the center axis of it while all three rotating bodies 31 are brought into contact with the inside surface of the steel pipe 50, the steel pipe 50 is rolled.
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