METHOD FOR MAKING HOLLOW SPHERICAL METALLIC ENVELOPE WITH TWO COAXIAL DIAMETRICALLY ARRANGED OPENINGS Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely manufacture of hollow spherical metallic envelopes with two coaxial diametrically arranged openings or with inner tube forming flow-through pass, possibly production of plugs of ball type hydraulic taps. SUBSTANCE: method for making hollow spherical metallic envelope with two coaxial diametrically arranged openings comprises steps of shaping spherical envelope due to realizing mutually opposite lengthwise forming of cylindrical metallic tube blank in two spherical die halves on inner mandrel arranged coaxially relative to said die halves at relation of outer diameter of tube blank to diameter of spherical cavity of die halves is less than 1; realizing shaping of spherical envelope by three stages; at first stage performing free lengthwise squeezing of end portions of tube blank of spherical envelope until time moment of loss of lengthwise stability of equatorial portion of tube blank; at second stage performing combined free lengthwise squeezing until contact of ends of tube blank with inner mandrel and budging-expanding equatorial portion of tube blank; at third stage performing combined squeezing-sizing of outer spherical surface of made spherical envelope at pushing ends of tube blank and making above mentioned coaxial diametrically arranged openings due to deforming ends of tube blank. When laminate cylindrical metallic tube blank is used, it is possible to make of tube members hollow spherical metallic laminate envelope. Invention provides enhanced control of boundary conditions at changing dimensional parameters of formed tube blank. EFFECT: enhanced stability, increased accuracy of process for shaping high-quality spherical metallic envelope, lowered probability of occurring wavy distortions of outer surface of spherical envelope. 5 cl, 5 dwg