METHOD FOR MAKING ENVELOPE OF FRAGMENTATION TYPE AMMUNITION Russian patent published in 2004 - IPC

FIELD: processes for making envelopes of fragmentation type ammunition, shells, grenades, mines an so on having on inner surfaces notches in the form of lattice of mutually crossing multistart riffles formed by three-dimensional deforming of tube blank material during two operations. SUBSTANCE: method comprises steps of reducing cold tube blank; deforming it in radial direction due to rolling around planetary rolling out head by means of rollers with use of central mandrel placed inside with gap and having helical ribs at axial motion of rotating tubular blank; providing gap equal to 0.3 - 0.7 of height of helical ribs of mandrel between freely mounted tubular blank and stationary mounted cylindrical central mandrel; turning rotation planes of rollers relative to direction of mandrel ribs by angle equal to 3 - 7 degrees in such a way that realizing forced feed of leading end of tubular blank for rollers of rolling out head being rotated in direction of helical ribs of mandrel. EFFECT: simplified process of making fragmentatin-type envelope with lattice of rhomb-shaped protrusions on inner surface, increased factor of metal use of tubular blank, enhanced efficiency of method due to combining reducing and rolling out operations and also due to removing worked tube by screwing it off from central tool. 5 dwg