| 摘要 |
PURPOSE:To considerably decrease the frequency of roll changes and to improve working efficiency by setting the calibers of 6 pieces of rolls at the diameters from the diameter of a stock circle up to 110%, then executing sizing. CONSTITUTION:The circular stock 2 is subjected to sizing with 2 units of 3- pieces roll rolling differing in the roll angle by 60 deg. at the final stage. The calibers 7 of 6 pieces of the rolls 1 are formed to the shapes disposed with the circular arcs of the diameters from the diameter size of the stock 2 up to 110% and adequate relief parts 3. The stock is then subjected to the sizing in the range from the stock diameter up to 85% of the diameter by selecting the drafts of the rolls. The sizing change of high out-of-roundness is possible according to such 3-pieces rolling; for example, 9 times of roll changes are merely necessitated while 100 times of the roll changes are heretofore involved in rolling of 22-120phi. The roll changes for the sizing changes are thereby considerably decreased and the efficiency is improved. |
