Study On Cross Wedge Rolling Uneven Temperature Field Composite Rolling Elongated Conical Step Shaft

Cross Wedge Rolling of shaft parts is a new plastic forming technology, which isrolling and forging interdisciplinary subject areas. It has very high production efficiency,higher utilization ratio of the material and low production cost; and was widely used inlarge, medium and small ladder shaft key parts manufacturing, such as railway vehiclesaxles, tractors axle.This thesis mainly studies the two roll cross wedge rolling elongated conical stepshaft，which adopted the uneven temperature field composite rolling method. The shaftcome from a new type of construction engineering equipment，and it also has extensiveapplication space in mechanical engineering field. Because of the finished part too fine toolong and step period of reduction of area larger, when the billet is a solid round bar, it isdifficult to roll forming. For that reason，we adopted composite rolling method that theoutside is tubular product and the inside is core rod.that is to say, using the method ofcross wedge rolling pressure the two part together,and at last meeting the requirementspressure between them.Based on the cross wedge rolling ordinary rolling principle, This thesis focus on theexploration research of cross wedge rolling composite rolling thin step shaft methods.Because two roll hollow rolling easy to produce the workpiece elliptic changephenomenon, and the composite rolling further intensifies the outer sleeve elliptic changetrend for the support effect of Core rod,which result in that after the rolling the finishedproducts can’t meet the requirement for producing certain gap between the two parts. Firstin the mold design through the predecessors’ research to hollow rolling and summary ofthe law, on other hand as far as possible through the improvement process parameters,reduce the elliptic trend. Secondly this article groundbreaking using lower outer sleevetemperature at the same time increase core rod temperature, in other words uneventemperature field method to reduce elliptic change, finally rolled into the finishedproducts.This paper firstly through the DEFORM finite element simulation method proof that the method of uneven temperature field is very effective in two roll cross wedge rollingcomposite rolling,especially to improve the outer sleeve elliptic tendency, reduce the gapbetween shaft sleeve and core rod, increase the core rod’s rolling reduction and strengthenthe metal’s liquidity of core rod. at the end, the paper select a suitable initial temperaturebased on the before research results. Secondly though the uneven temperature fieldcomposite rolling method, simulated rolled the elongated conical step shaft and thoughcontrast round bar solid rolling stress strain rule get the finished part that meet therequirements.