METHOD AND DEVICE FOR PREFORMING PRECEDING AND SUCCEEDING END OF SLAB BY PRESSING

摘要

PURPOSE:To improve the shape of a crop and to improve the yield in rough rolling by preforming the front and rear end parts of a slab under specific conditions except the specific length thereof by pressing in using trapezoidal dies having parallel surfaces facing each other with the slab in-between and tapered surfaces provided on both sides of the plane surfaces. CONSTITUTION:A press die 20 for preforming of a slab prior to hot rough rolling is made into a trapezoidal shape having a parallel surface 30 on the side facing the parallel surface of the other die with a supply material, e.g. a slab 4, in-between, and having a tapered surface 32 sloping outward at an angle theta to the central axis in the longitudinal direction of the slab 4 from the front end part F and rear end part R of the surface 30. The slab is rolled with such dies 20 except the press width LA to be not rolled down at the foremost end of the slab under the conditions of 0<=LA/Wo<0.5, 10 deg.<=theta<=30 deg., 0.3