EXTRUSION METHOD Russian patent published in 1998 - IPC

FIELD: plastic metal working, namely processes for extruding builtup-thickness blanks for making tubes with clad working surface. SUBSTANCE: method for extruding builtup blanks with lengthwise laminarity includes steps of placing one hollow blank inside another with inner blank made of less strength material; mutually fixing blanks, heating builtup blank and extruding it through hollow cone die due to arranging said blank onto needle, placing it in container and applying effort to end of said blank through pressure pad. Blank is fixed by two stages. At first stage inner blank is placed only along a part of length of outer blank. Supporting ends of blanks are arranged in different planes. Axial compression effort is applied to working end of inner blank causing common radial deformation of both blanks. At second stage supporting end surfaces of blanks are coincided due to applying axial compression effort to supporting end surface of inner blank and simultaneously forming slope on one end of builtup blank. Inner blank is placed onto needle by angle relative to cone die. At extrusion process axial shift of material of less strength blank is provided relative to material of more strength blank in direction of applied effort. Said axial shift is provided due to transmission of compression effort to blank end through pressure pad having annular protrusion with diameter equal to outer diameter of inner blank. EFFECT: enhanced efficiency. 9 dwg