US12331372 - Steel compositions, methods of manufacture and uses in producing rimfire cartridges

This patent describes a method for processing steel compositions specifically for rimfire ammunition cartridges, involving multiple cold rolling and annealing steps to achieve desired thickness reductions. The resulting steel is then suitable for use in producing durable and effective rimfire cartridges through continuous plating.

Claim 1

1. A method of processing steel of a rimfire cartridge, the method comprising: obtaining a steel composition having an original thickness; performing a first cold rolling of the steel composition; producing the steel composition having a reduced thickness, wherein, the reduced thickness constitutes a reduction of about 30% to about 70% of the original thickness; performing a first annealing and subsequent cooling of the steel composition having the reduced thickness; performing a second cold rolling of the steel composition having the reduced thickness, following the first annealing and subsequent cooling step; producing the steel composition having an additional reduced thickness, wherein, the additional reduced thickness constitutes an additional reduction of about 20% to about 35%; performing a second annealing and subsequent cooling of the steel composition having the additional reduced thickness; and continuous plating one or more of: the steel composition having the reduced thickness, following the first annealing and subsequent cooling step; and the steel composition having the additional reduced thickness, following the second annealing and subsequent cooling step. obtaining a steel composition having an original thickness; performing a first cold rolling of the steel composition; producing the steel composition having a reduced thickness, wherein, the reduced thickness constitutes a reduction of about 30% to about 70% of the original thickness; wherein, the reduced thickness constitutes a reduction of about 30% to about 70% of the original thickness; performing a first annealing and subsequent cooling of the steel composition having the reduced thickness; performing a second cold rolling of the steel composition having the reduced thickness, following the first annealing and subsequent cooling step; producing the steel composition having an additional reduced thickness, wherein, the additional reduced thickness constitutes an additional reduction of about 20% to about 35%; wherein, the additional reduced thickness constitutes an additional reduction of about 20% to about 35%; performing a second annealing and subsequent cooling of the steel composition having the additional reduced thickness; and continuous plating one or more of: the steel composition having the reduced thickness, following the first annealing and subsequent cooling step; and the steel composition having the additional reduced thickness, following the second annealing and subsequent cooling step. the steel composition having the reduced thickness, following the first annealing and subsequent cooling step; and the steel composition having the additional reduced thickness, following the second annealing and subsequent cooling step.

Google Patents

https://patents.google.com/patent/US12331372

USPTO PDF

https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/12331372