METHOD FOR PREVENTING GENERATION OF BURR AT THE TIME OF PIERCING PIPE MATERIAL WITH PIERCER

摘要

PURPOSE: To prevent formation of burrs at the rear end of a base pipe in production of the base pipe for production of a steel pipe by piercing of a pipe material billet by a piercing plug and piercer roll. ;CONSTITUTION: The rear end face 7 of the pipe material billet 1 is heated to a high temp. to melt by a gas cutter, such as gaseous acetylene and oxygen flame or gaseous plasma flame, etc., from a gaseous flame nozzle 2 before piercing, by which the billet is provided with a line groove 4 having a proper width and depth in a method for obtaining the base pipe for production of the steel pipe by piercing of the pipe material billet 1 by the piercing plug and the piercer roll. The shape of the line groove 4 is formed to a minus or cruciform shape and further, preferably, the size of the line groove 4 is set at a width 5 to 6mm and depth 7 to 8mm.;COPYRIGHT: (C)1995,JPO