| 摘要 |
FIELD: powder metallurgy. SUBSTANCE: method to produce high density powder pieces with longitudinal bulges and grooves provides for moulding of simple form blank, its heating and hot additional compaction with piece form shaping by tool, surface of which is opposite to required form of piece. Grooves form shaping is exercised by pressing in process of transversal (radial) pressing by shaping tool with wedge-shaped intake part of its shape-making protruded members. Blank is moulded with diameter of profiled surface, that is not equal to diameter of bulges of formed profile and defined by formula D= K•D, with K =- coefficient of preliminary compaction in case of using pieces with outer (n = - 1) or inner (n = +1) location of gears; Kf = (Do / Di)- coefficient of piece form; Do and Di - outer and inner diameters of piece correspondingly; &thetas;, &thetas;- values of relative density of preliminary compacted blank and moulding correspondingly; Db and Dp - diameters of blank profiling surface of simple form and bulges of formed profile of piece; hot additional compaction is exercised by preliminary preceding to pressing in compaction of blank till porosity of 0.08 - 0.01 with its following form shaping into piece by tool with angle of its intake part 11 - 15 deg an by punch with butt forming cavity in the form of semitore with radius defined by formula r = (1 - m) (Ds - ds), with r - radius of forming cavity profile made in the form of semitore; Ds and ds - diameters of spaces of between teeth of outer and inner gear crowns of piece; m = 0.35 - 0.65 - coefficient considering nonuniform of blank butt surface deformation; and calibrating of moulded piece in process of form-making of next piece. EFFECT: increased productivity. |
