EXTRUSION METHOD Russian patent published in 1998 - IPC

FIELD: plastic metal working, namely extrusion of builtup hollow ingots for making tubes with clad working surface. SUBSTANCE: method of extruding, mainly builtup ingot including two placed one into another hollow blanks with inner blank made of less strong material comprises steps of assembling ingot, mutually fixing blanks, heating ingot, placing it onto needle for subsequent extrusion through cone die due to arranging it in container and applying axial compression effort to ingot end through pressure pad. Said builtup ingot is assembled of different-size blanks. At fixing said blanks one relative to another slope is formed on one end of said blanks. At placing ingot onto needle said slope is turned to side of cone die. In extrusion process deforming effort is applied to pressure pad provided with annular recess coaxial relative to its opening and having diameter more than that of blank with less strong material. Free space of said annular recess is filled by said less strong material at displacing said material relative to more strong one in direction opposite relative to direction of deforming effort. EFFECT: enhanced efficiency. 4 dwg