METHOD OF PRODUCING SEAMLESS PIPE AND APPARATUS FOR PERFORMING THE SAME

In the production of a seamless steel tube by piercing-rolling a heated billet with a piercing machine to form the billet into a hollow blank, and without reheating the hollow blank, by successively subjecting the hollow blank to elongation-rolling with an elongation-rolling mill and diameter-adjusting rolling by a diameter-adjusting rolling mill, it is made possible to prevent non-uniform longitudinal temperature distribution from occurring in a steel tube after diameter-adjusting rolling and enable energy saving to be accomplished by including a step 1 of measuring a temperature of the hollow blank along a longitudinal direction at the exit of the elongation-rolling mill; and a step 2 of spraying water onto the hollow blank to cool the hollow blank at the entrance of the diameter-adjusting rolling mill according to a measured longitudinal temperature distribution of the hollow blank, whereby the longitudinal temperature distribution of the hollow blank becomes uniform.