Design And Numerical Simulation Optimization Of The Blocking Roll Forging On A Crankshaft

The crankshaft, as one of the key components of bearing load and transmittingpower, is one of the five component in the engine (cylinder head, camshaft, connectingrod, crankshaft, organism), which is the most difficult to guarantee machining precision.Crankshaft shape model and the principle are very complicated, which largely affect theengine performance development and manufacture. Crankshaft working environment isvery poor, the crankshaft undertook alternating stress, torque force and deformation inhigh speed reciprocating cycle. If the mechanical performance of crankshaft is belowthe standard and the crankshaft is destructed, which will lead to huge losses. So theseindex requirements of crankshaft such as the tensile strength, surface strength, wearresistance, heat treatment and dynamic balance performance put forward higher request.Crankshaft structure is very complex, this article adopts the new type of blocking rollforging process to study crankshaft forming process, design optimization of roll forgingdie, and finally achieve the purpose of raise the utilization ratio of materials.This article aiming at the blocking forging process of a crankshaft, calculating theroll forging crankshaft blank drawing according to the3-D chart, designing andoptimizing roll forging blank drawing according to the roll forging process and thestructure characteristics of crankshaft, application of numerical simulation model of dieforging forming to verify the feasibility of roll forging blank drawing. According to theforging size obtained by optimization design of roll forging drawing, combining forgingfigure size blank choice, determine the crankshaft of the original blank size for φ125mm×540mm. In roll forging die design, determine the roll forging for2times;determine the blocking of roll forging type slot for: round-oval-round. Aftercompletion of roll forging die design, simulate and optimization analysis of blockingroll forging technology. In the blocking simulation of roll forging process, application ofcontrol variable method, to meet the two conditions of the length of the request forgingand the minimum forging forming load force, the optimal simulation parameters are:billet initial temperature is t=1180℃, friction factor is μ=0.8, the roll forging machinespeed is α=2rad/s. In the matching of blocking roll forging process, in the first time thecoordinate of billet clamping end is (﹣110，0，0), in the first time the coordinate ofbillet clamping end is (﹣130，0，0), in this case won’t appear "small ears" defect. Diestructure parameters were optimized based on orthogonal test table, in the parameters which affecting the service life of mould, various factors from the primary to the secondis: into the die fillet, transition slope, transition fillet. To make the wear and tear of moldminimum, the combination optimal size are: into the die fillet is20mm, the transitionfillet is25mm, transition angle is40°, in this case, the measure of the wear and tearof the mold is0.739μm.In this paper, in order to verify advantages and disadvantages between moldforging forming under blocking roll forging and mold forging forming undernon-blocking roll forging, From the original blank, forming load, flash spreading, metalstreamline four aspects has carried on the comparison and analysis, to verify the finalforging of blocking roll forging processes is better than that of original process.Production test, under the blocking roll forging process, the crankshaft forging hasbetter filling, flash spread out more evenly, greatly improve the utilization rate ofmaterials from the original78.9%to present83.2%.