PRODUCTION OF METALLIC MATERIAL HAVING CIRCULAR SECTION

摘要

PURPOSE:To improve size control by turning a rotary housing by a prescribed angle in a positive or negative direction when the shortest distance between each roll surface and a pass line increases or decreases then rolling a material. CONSTITUTION:Chocks 5, 6 of each rolling roll 2 are fixed in prescribed positions and the rotary housing 8 can be turned forward and backward in arrow H, I directions from the turning center position. The fluctuation range of the turning angle of the housing 8 and the change rate of the roll gap in this stage are preliminarily determined. The chocks 5, 6 and housing 8 of a cross helical rolling mill 1 are then positioned in the initially set state and the rolling material is rolled by the mill, by which a semi-finished product is obtd. The outside diameter of the semi-finished product is measured over the entire length to make a dimensional change pattern. A means 11 for operating turning operates the turning of the housing 8 according to the pattern in the actual rolling. The accuracy of the outside diameter size in each lot is improved by the above-mentioned method.