Patent ID: 9375772
Filing Date: 2016-06-28
CPC Classification: B21D,B65D

Claim Text:
1. A method to form a disposable compressed gas cartridge, comprising: providing a steel sheet; using sequentially (N) progressively longer dies to form from said steel sheet a vessel comprising a cylindrical wall, a closed end, and an open end, wherein said cylindrical wall comprises a body diameter, and wherein (N) is greater than or equal to 5; prior to forming a tapering neck structure, heating a first portion of said vessel at an annealing temperature of about 700° C. to recrystallize a ferrite phase followed by cooling in still air, wherein said first portion includes said open end and a portion of said cylindrical wall adjacent said open end, and wherein said vessel excluding said first portion is not heated to said annealing temperature; using sequentially (M) tubular dies to form a cartridge neck by progressively narrowing said first portion of said vessel from said body diameter at a distal end of said first portion to an open end diameter at said open end to form an empty gas cartridge, wherein said body diameter is greater than said neck diameter.