To coincide the center of a mill stand with the center of a rolling roll about all inner housing in a pipe mill for producing many kinds.
This method is a mounting method of an inner housing in a three-roll type pipe mill. When expressing the force by which the inner housing 33 is pulled in the mill stand 34 by Fp, the horizontal component of force of the clamping force of the inner housing 33 by Fcx and the component of force in the horizontal direction of a screw 38 by Fsx, the inner housing 33 is clamped by the clamping force which satisfies Fp+Fcx>0.2×Fsx after the inner housing 33 is pulled in by the pulling-in force which satisfies Fp>0.1×Fsx. When the housing is mounted, the closely contacting state of the housing 33 with a fixing stopper 35 is detected on the basis of the rising value of the pressure in pneumatic piping of the air which is blown out of the stopper surface 35a of a fixed stopper 35 installed on the mill stand 34. By this invention, the generation of off-center is prevented and the quality of rolling is improved.
ISHIHARA NOBORU
USHIJIMA TOKUJI
Tetsuya Mizogami
Yoshinori Iwahara