PRODUCTION OF INTERNALLY GROOVED PIPE

摘要

PURPOSE:To avert the breakage of a metallic pipe in the stage of heading and to enable production of a titled pipe by holding a floating plug with segmental dies having a prescribed inside diameter, heading the metallic pipe by said dies, and holding the pipe with a supporting die after retreating of the segmental dies. CONSTITUTION:Segmental dies 20 having an inside diameter approximately equal to the numerical value obtd. by adding the value of two times the wall thickness of a metallic pipe 2 to the outside diameter of a grooved plug 4 are disposed in the position backward of a supporting die 10 in the advancing direction of the pipe. While a floating plug 8 is held by said die 20, the heading of the pipe 2 is performed and thereafter the die 20 is retreated and the plug 8 is held by the die 10, then the pipe is subjected to stationary grooving by the plug 4 and plural rolling rolls 12. The grooved pipe 2 is further drawn by a finishing die 16 so that the outside surface thereof is corrected.