METHOD OF MAKING GRID OF GROOVES ON INNER SURFACE OF SHELL AND DEVICE THEREFOR Russian patent published in 2016 - IPC B21K21/16 B21J13/00 B21D17/02 B21D37/00 B21C37/20 

FIELD: metallurgy; technological processes.

SUBSTANCE: invention relates to metal forming and can be used for production of shells with array of grooves on inner surface. For formation of riffles, method uses a hollow working mandrel with a longitudinal cut and with mesh ledges on outer surface. Shell is installed in container, mandrel is introduced therein with clearance and flexible distribution with last tool rod is performed. As a result, array of recesses is formed on inner surface of shell, except section adjacent to longitudinal section of working mandrel. Expansion is performed with coefficient of expansion, which is determined from given ratio. Tool rod and mandrel are then removed from shell and shell or mandrel is turned about an axis by an angle of 90÷180°. Subsequent repeated introduction in shell cavity of mandrel provide location of its ledges in previously formed recesses of shell. Elastic mandrel is performed again, and an array of recesses on raw section surface of shell is formed.

EFFECT: as a result of riffles having different shape and dimensions are obtained.

2 cl, 5 dwg, 1 ex