Study On A New Forging Process And Toolings For The Crank Of Large Marines

Large marine crankshaft, which plays a crucial role in the engine’s stable and safeoperation, is a key component of large marine engine. With the rapid development ofeconomy in our country, more ships, therefore several hundred large marine crankshaftsare needed every year. This crankshaft is a very expensive part, so improving theutilization coefficient of material of the forgings can produce a huge economic benefit.Among the methods for producing the crank forgings, Bending-forging is the onebeing widely used in our country. Because it is only a short time since we began tomanufacture large marine crankshaft and this method has not become perfect, someproblems are appeared, the most critical one is the low utilization coefficient of material,which increases the manufacturing costs. In this article the forming process of largemarine crank is numerically simulated starting from the deforming properties of thematerial, aiming at increasing the utilization coefficient of material.The high temperature compression tests of the material are conducted for differenttemperatures and strain rates, and the real stress-strain curve is abstained, Based on thisthe constitutive equation of the crankshaft material S34MnV is got by means of theZener-Hollomon Parameters method. Then analysis of the deformation characteristics ofthe material is made for different deformation conditions.Using the rigid-plastic finite element analysis software DEFORM-3D, with the realstress-strain curve and the constitutive equation of S34MnV, the bend-forging process ofthe 6S60MC-C marine crank being used now is simulated numerically. From analyzingthe characteristics of the process, the shape defects and its reason are found.A new forging process that can reduce the overall forging allowance is presented bychanging the structure of the dies. At last numerical simulation research of the newprocess is preceded, and the results show that the new process can meet the demands ofthe forgings quality and reduce the material consumption.