METHOD FOR PRODUCING RIFFLES ON OUTER SURFACE OF SHELL Russian patent published in 2021 - IPC B21K21/00 B21C37/20 

FIELD: metallurgy.

SUBSTANCE: invention relates to pressure metal treatment, namely, to the manufacture of parts such as shells, on the outer surface of which there are riffles. A method for producing riffles on the outer surface of the shell, in which the protrusions of a hollow working mandrel with a longitudinal section are inserted and the finished shell is subsequently removed, while the shell with an outer diameter of D₃ is placed in the cavity between the punch and the hollow working mandrel, made with protrusions on the inner surface in the shape and size of the required riffles, and has a longitudinal section equal to Z_wm=2×π×(Z+H), where Z is a one-sided gap equal to Z = 0.25 … 1 mm, H is the height of the protrusions of the hollow working mandrel, the protrusions of the hollow working mandrel are inserted on the outer surface of the shell by crimping the hollow working mandrel with a matrix with a crimping coefficient by means of the matrix until the longitudinal section Z_wm disappears, after which the matrix is removed from the hollow working mandrel with its elastic distribution to the initial position.

EFFECT: invention makes it possible to apply riffles of any shape and size on the outer surface of the shell in one operation.

1 cl, 5 dwg