Inclined rolling mill, method for producing seamless pipe and method for producing seamless steel tube

摘要

This invention provides an inclined rolling mill capable of preventing a defective shape of the rear end unstationary portion of the seamless tube.An inclined rolling mill, which is a slanting rolling mill, and an inclined outer diameter rolling mill, which is followed by a slanting perforation mill, is provided with a distance LS (mm) between the rolling portion of the perforated roll roll and the rolling portion of the outer diameter rolling roll satisfying the following formula (1), and the roll spacing ds of the plurality of outer diameter rolling rolls is as follows The equation (2) is satisfied.3 × (1.2 Po + 2G). Ltoreq.ltoreq.0.8bl. (1)1.2 Po + 2G > DS ≧ DB + 2GIn the equations (1) and (2), Po is the outside diameter (mm) of the plug, G is the distance (mm) between the plug and the perforated rolling roll, BL is the length (mm) of the bar, and DB is the outside diameter (mm) of the bar.