METHOD FOR OPERATING SEAMLESS PIPE MANUFACTURING PLANT

摘要

PURPOSE:To keep a rolled stock temp. at the outlet side of cooling bed without stopping line or thinning the rolled stock by extending staying time in a reheating furnace according to the temp. of rolled stock at the outlet side of cooling bed and further, if necessary, delaying ejecting pitch in a heating furnace. CONSTITUTION:A billet heated in the heating furnace 21 is made to a steel pipe with a piercer 22 and a mandrel mill 23, and further, by raising the temp. thereof with the reheating furnace 24, the steel pipe is made to a seamless pipe having the finish size with a stretch reducer 25, and after that, the pipe is cooled in the cooling bed 26 and successively, shaped with a shaping line 27. In operating method in the above seamless pipe manufacturing plant, the ejecting pitch of billets in the heating furnace 24 is adjusted so as to correspond to the critical process. Further, in the case the measured temp. of rolled stock at the outlet side of cooling bed 26 exceeds the aimed value, the ejecting pitch in the reheating furnace 24 is extended as longer as possible and number of the rolled stocks coming into the cooling bed 26 is reduced. If necessary, the ejecting pitch in the heating furnace 21 is increased so as to correspond to the ejecting pitch in the reheating furnace 24. By this method, the temp. of rolled stock at the outlet side of cooling bed 26 is kept to the prescribed temp. without partially stopping the line or thinning the rolled stock on the line.