Crank Forgings Forging Process Numerical Simulation Studies

Crankshaft is the key component for the diesel engine of large ships. Whenit's working, the forces of the crankshaft are always complicated. Therefore thequality of the crankshaft is an important factor which have influence on theengine's properties and reliability. Production method of oversize crankshaft iscombination method. Firstly several crank forgings are produced, and thenassemble them into an entire crankshaft after machining. Material utilization oftraditional manufacturing processes which are used for producing largecrankshafts is always low. The crankshafts have low forging precision and theyneed large machining volume. While the capacity of the forming equipment islarge enough, we can use the impression-die forging to improve forgingprecision and integrity of the metal fiber. In this way we can also reducemachining volume and improve the quality of the crankshaft. At present there islittle research on large crankshaft impression-die forging.In this article, the author briefly introduced the features of theimpression-die forging process of the oversize diesel engine crankshaft, andparticularly introduced the studies of the crankshaft impression-die forgingprocess and numerical simulation in detail.According to the size and structure of the crank forgings, the shape of theforgings and forging process are designed reasonably in this article. By the useof the UG system, the three-dimensional model of the crank forgings has beenset up parametrically. And related issues of the forging process and die designare analyzed. Based on the rigid-plastic finite element method, the crank forgingprocess of the RR (TR) integrity fiber method has been simulated by use of thenumerical simulation software DEFORM-3D. Proper parameters are set beforesimulation. The rule of metal flow, the distribution of the strain, stress,temperature field, as well as the time-load curve of the forming process havebeen obtained and analyzed through simulation results. Although a good crankforgings is obtained, the load of the press is too large. The horizontal upsettingforce reaches as high as231thousand tons. To solve the problem of large load, the author improves the forging process and the dies by adding upsetting stepand related dies as the final forging. Through simulation a good forgings isobtained and the load reduces to a rational level of68.6thousand tons.Obviously, the large crank forgings can be produced by the80thousand tonspress. Through the computer numerical simulation, the better formingparameters of the crank forgings are found as follows, temperature:1150℃,punch velocity(vertical):9.6mm/s, die velocity(horizontal):9.7mm/s, thefriction coefficient:0.3, size of billet: φ755mm×3500mm. Process parameterssuch as forming force and the maximum stress are reliable and these parametersprovide basis for crank impression-die forging process and the die design.