METHOD OF CUTTING END OF STEEL PIPE ON HOT PIPE DRAWING LINE

摘要

PURPOSE:To aim at enhancing the yield by cutting out a pipe end by a minimum value of end cutting lengths which are determined from the result of measurement of wall thicknesses of steel pipes fed onto a cutting table when thus determined end cutting lengths all exceed a planned length, but by cutting out pipe end parts by a maximum end cutting length when thus determined end cutting lengths are all below the planned length. CONSTITUTION:A steel pipe fed out from a finishing rolling mill 1 is continuously measured for its wall thickness in the axial direction thereof by a wall thickness measuring deice 10, and measured values are delivered to a control device 11 which previously stores therein a tolerance for wall thickness and a predetermined planned cutting length. The control device 11 calculates and stores the length of pipe end part which is out of the tolerance, as a cutting length while the cutting length is compared with the predetermined planned cutting length, and is stored for every steel pipe. When a plurality of steel pipes are shifted onto a parallel conveying table 4, the distance L between a stopper 6 and a cutter 5 is determined. When the cutting lengths of the steel pipes on the table 4 all exceed the planned cutting length, the distance L is set to a minimum value of cutting lengths when the cutting lengths of the steel pipes all exceed the planned cutting length, but is set to a maximum value of the cutting lengths when they are all below the planned cutting length.