JPS5588910A - Controlling method for rolling work for pipe - Google Patents

Abstract

PURPOSE:To roll the pipe blank while setting and controlling the peripheral speed of reducing rolls in order to manufacture the finished pipe with wall thickness, etc., uniform over the entire length, according to the complementary variation pattern determined depending on the variation pattern obtained from the actual measurements of wall thickness, etc., over the entire length of the finished pipe being subjected to the previous rolling. CONSTITUTION:The mandrel 2 with the same specification as that of the actually used mandrel is inserted into the pipe blank with the same specification as that of the pipe blank 1 to be rolled; and the test rolling is worked on the pipe blank 1 by each reducing roll 31a-38a; after that, the wall thickness of the pipe blank 1 is actually measured over the entire length of the pipe blank 1; hereby, the variation pattern X of the wall thickness is obtained. Next, the aim wall thickness pattern Y being under the comlmentary relation with above variation pattern X is determined. Besides, Z is for the aim value. Then, the peripheral speed of rolls 31a-38a, necessary for rolling the pipe blank 1 into the finished pipe possessing the pattern Y, is determined and is previously memorized in the controller 4; and the pipe blank 1 is rolled while controlling the peripheral speed of each roll 31a-38a. As a result, the rolling work is carried out so as to eventually cancel the thick walled parts A, B, or thin walled parts C, D; hereby, the rolling accuracy for the wall thickness, outer diameter, etc., of the finished pipe is remarkably improved.