| 摘要 |
997,811. Cupping. BUDD CO. April 6, 1962 [April 19, 1961], No. 13398/62. Heading B3Q. A method of forming a thin metal sheet into deep-drawn configurations is characterized by the steps of bonding the thin metal sheet to a thick metal sheet to produce a laminated sheet, of forming the laminated sheet in a forming machine having a male die, and completely removing said thick sheet of said laminated sheet from the thin sheet article. The laminated sheet 10 is cupped in an hydraulic press comprising an hydraulic cylinder 14 which actuates an upper hold-down ring 16 to grip the sheet against a lower stationary ring 18 with sufficient pressure to prevent buckling during the cupping operation. A cupping die 26 is actuated by an hydraulic cylinder 22. After the cupping operation the thicker sheet 28 is removed by heating or chemical etching after the formed laminated sheet has been annealed to remove any internal stresses created by the cold working. In an embodiment the laminated sheet comprises a thin stainless steel sheet 27 bonded to a relatively thick carbon steel sheet 28 by soldering, brazing, welding or hot roll bonding. The thick sheet is at least five times the thickness of the thin sheet and the blank lying between the blank holders is lubricated to create a uniform coefficient of friction in the blank holders. The hold-down pressure is held constant by providing a draw bead groove and mating projection on the hold-down rings. The thin sheet maintains its original thickness during the deep drawing operation. In another embodiment a hemisphere is formed from a laminated blank comprising a sheet of stainless steel sandwiched between two supporting layers of carbon steel. Two such hemispheres may be welded together to form containers for rockets or missiles. Specification 871,269 is referred to. |
