Patent GB-759902-A (GB)
Title: Improvements in cold shaping of steel
IPC: B21C23/03
Filed: 1952-05-23
Abstract: 759,902. Forging; extruding. AMERICAN RADIATOR & STANDARD SANITARY CORPORATION. May 23, 1952 [May 24, 1951], No. 13095/52. Classes 83 (2) and 83 (4). Making cupped articles.-A method of cold forming a tubular steel article having a circumferential enlargement on its exterior surface comprises forming a solid steel blank into a tubular blank 75, Fig. 5, having. internal and external shoulders 74, 70 respectively, inserting this blank in a die 80, Fig. 6, and extruding it by a punch 86 to form an elongated blank 95 having a thickened wall portion 97, and thereafter displacing the metal of the thickened wall portion radially outwardly to form a circumferential enlargement 105, Fig. 7. The solid starting blank, Fig. 1 (not shown), may be of square, rectangular, hexagonal, or preferably round cross-section and is of steel containing up to 0.4 per cent carbon. A preferred steel contains the following percentage composition: 0.1-0.12 C, 0.4- 0.6 Mn, 0.04 S, 0.04 P. The blank is first sized in an extrusion die 10, Fig. 2 (not shown), having slightly tapered side walls; it is then inserted in a second die 28, Fig. 3, having slightly tapered side walls 30, 32, and is pierced by a punch 37, having a rounded corner 40 of this kind described in Specification 718,506, during which backward extrusion takes place. An ejector 35 removes the blank 27 from the die. The blank is then annealed or normalized at about 1450‹ F. to reduce the hardness due to cold working. A second backward extrusion operation is then effected to produce the blank 55, Fig. 4 (not shown); this blank is then subjected to a final backward extrusion operation in a die 60, Fig. 5, having slightly tapered side walls 64, 62, by means of a punch 69 having a nose 66, 67. An ejector 71 is provided. During this operation the side wall 78 has been hardened by cold working. The blank 75 thus produced is forwardly extruded in the die 80, Fig. 6, by means of the punch 86 having a stepped nose portion 87, 90. The side wall 94 of the blank 95 thus produced has been work hardened to the final desired hardness but the side wall 97 is slightly less hard. The enlargement 105, Fig. 7, is formed by upsetting in a die 100 by means of a punch 102 having a tapering nose 104. During this operation the lower portion of the article 106 is further work-hardened so as to produce the same hardness as the side walls. The upper end 98 of the article, Fig. 6, may then be machined and the article subjected to a stress-relieving treatment at 750‹ F. In another embodiment a cup-shaped blank 110, Fig. 12 (not shown) formed by backward extrusion and having a stepped. cavity is forwardly extruded to form a blank 126, Fig. 8 (not shown); the blank is then upset in a two-part die 131, 132, Fig. 9, by means of a punch 140, to produce a circumferential enlargement 144. In a further embodiment, an extruded blank 150, Fig. 13 (not shown), is forwardly extruded to produce an elongated blank 175, Fig. 10 (not shown), which is then upset in a two-part die 181, 182, Fig. 11, by means of a punch 197 to form a double enlargement 187, 188 on the exterior of the tubular article. The latter may be open at both ends.