GB1428764A - Method of and apparatus for cooling metal bars heated to a high temperature - Google Patents

Abstract

1428764 Rolling mill plant NIPPON STEEL CORP 19 Feb 1973 [23 May 1972] 7983/73 Heading B3M [Also in Division B8] Metal billets are turned and cooled while conveyed over a bed 3 in groups, air cooling taking place in zone I and water spray being used in zone II. The cooling and conveying bed, Figs. 6, 7, comprises fixed supports 11 with pivotable dogs 12, and horizontally movable supports 21 having pivotable dogs 28 and upwardly extending projections 22. When the supports 21 are reciprocated horizontally the billets are maintained in groups but, as each billet travels down the sides 25 of the projections 22, it is turned about its longitudinal axis, Fig. 8. In a modification, Fig. 9, a rotatable disc 41 and crossmember 43 are mounted on each support 21, in place of the projection and dogs 22, 28. A further construction, Fig. 10, comprises conveyer chains 45 having pushers 46 the billets being turned as they pass over a fixed projection 47. In Fig. 4, means for transferring billets in re-arranged batches from zone I to zone II comprises a lifting device 6 which places the groups on a roller table 8 (also Figs. 3a, 3b, not shown). The number in each group is chosen to match the capacity of a magnetic crane device (10, Fig. 5, not shown). Cooling details.-In zone I the air cooling reduces the billet temperature from approximately 1100‹ to 600‹ C., the rate of turning and the contact between adjacent billets in a group minimizing distortion of the billets. Distortion in zone II is also minimized by intermittent operation of water cooling sprays 4, the periods of interruption reducing the temperature differential of each billet. Cooling zone II has a range of 650-250‹ C. approximately. The speed of operation of the bed(s) is varied according to the cross-section dimensions of the billets. The billets may be of circular section.