Patent ID: 8464568
Filing Date: 2013-06-18
Classification: B21B,C21D

Abstract:
1. A production method of a seamless pipe or tube comprising the steps of: heating a billet in a heating furnace, subjecting the heated billet to piercing and rolling by a piercer to produce the hollow shell, applying a lubricant containing carbon to a mandrel bar, subjecting the hollow shell to drawing and rolling in a mandrel mill using the mandrel bar to which the lubricant is applied, to produce a material pipe or tube, and reheating the material pipe or tube in a reheating furnace, wherein when a temperature of the material pipe or tube is 550° C. or higher and 1000° C. or lower in the reheating step, an oxidizing gas is fed into the material pipe or tube, a flow rate of the oxidizing gas being determined so as to satisfy the condition of the following equation (1): wherein Q represents a flow rate of the oxidizing gas [Nl/sec], T