METHOD FOR MANUFACTURE OF SMALL ARMS CARTRIDGE CASE Russian patent published in 2001 - IPC

FIELD: plastic metal working, applicable in production of cartridges of small arms of various purpose. SUBSTANCE: method consists in punching of a disk, manufacture of a hollow semi-finished item, drawing of the hollow semi- finished item with thinning of the wall, chemical heat treatment and a complex of shape-changing operations for formation of the primer cap seat, formation of the flange in the bottom part of the cartridge case and facing of the cartridge case and facing of the cartridge case in length, the volume of the disk equals 1.12 to 1.30 of the volume of the finished item, and the thickness exceeds 0.7 of the bottom thickness of the semi-finished item of the last drawing. A cup-shaped semi-finished item is produced by volume punching with a bottom external band having a diameter equal to 0.95 to 1.1 of the cartridge case diameter in its bottom part, the band height not exceeding 0.9 of the thickness of the source disk, and bottom thickness equal to 1.0 to 1.3 of the thickness of the bottom of the semifinished item of the last drawing. The outer surface of the cup-shaped semifinished item is made tapered with the taper angle equal to 8 to 60 deg. The wall of the cup-shaped semi-finished item has a thickness uniformly converging from the bottom part to the edge with a varying cross-section area in height. The obtained cup-shaped semi-finished item is subjected to a recrystallizing softening annealing and pickling, after that one or two drawings are accomplished with a thinning of the walls, which form the mechanical properties of the cartridge case body. EFFECT: improved quality of cartridge case, reduced waste for facing of cartridge case, preset distribution of the mechanical properties in height of the cartridge case walls with its reduced value from the bottom to the neck, reduced number of shape-changing operations. 2 cl, 6 dwg, 1 tbl