ANNULAR PRODUCT MANUFACTURING METHOD Russian patent published in 1994 - IPC

FIELD: plastic working of material. SUBSTANCE: method involves effectuating expansion in two successive stages. At the first stage turning of section through a predetermined angle is accomplished due to initial nonuniform reduction section along the height of workpiece. At the second stage, when uniform reduction section along height is provided, uniform increase in diameters of workpieces subjected to expansion is effectuated simultaneously along the full height of section to achieve predetermined values. At each stage reduction is determined as function of variation in initial, current and final parameters of annular products. EFFECT: increased quality of annular products by providing uniform reduction section. 2 cl, 2 dwg