The Numerical Simulation Of Hot Forging And Process Optimization Of Engine Crankshaft

Crankshaft is a very important parts in automobile engine, when it working, it withstand the complex forces. It always bear alternating stress load. Besides this, it also bear own inertia and centrifugal force caused by self rotation. In order to ensure the normal work of the automobile engine, the crankshaft should have sufficient strength,enough hardness, impact toughness, wear resistance, fatigue resistance corrosion resistance and so on. The crankshaft forgings is complex and difficult. During the forming process, it may be folded,filling incomplete, deformation etc.This article study on 06d02 crankshaft. It simulated the process of hot forging process for the crankshaft including pre-cooling before forging, pre-forging, the final forging by DEFORM-3D. Analysis the temperature filed, stress filed, strain filed, velocity field during the hot forging process to predict the problem may occurs such as the fold, filling ineffective,etc.Usually the defects are reduces by optimizing process parameters during hot forging of crankshaft in actual production.Study research on the effect of the thickness of flash on forging angle,setting the thickness of flash as 10mm、8mm、6mm、4mm to simulate the forging process. Only when the thickness is 6mm, the body of forging did not turn up folding angle. The rate of deformation of forging effects the strain、stress distribution and deformation uniformity.Setting the rate as 100mm/s, 200mm/s, 300mm/s, 400mm/s to simulate the hot forging,only when the speed is 100mm/s,the stress and the strain distributed well. The heat temperature also make difference on forging quality. At last chosen the thickness of flash as 4mm, 5mm, 6mm,the deformation rate as 80 mm/s, 100 mm/s, 120 mm/s,billet initial temperature 1170 ℃, 1220 ℃, 1270 ℃, to have orthogonal optimization. The result shows when the thickness of flash is 4mm, the speed is 80mm/s, the temperature is 1220℃,the load is in low level. And then simulated the crankshaft process by optimized process parameters, compared the result with the original process. The result shows that both the pre-forging load and the final forging load all reduced,and the load in forging the process rising velocity decreased. Article also optimized the radius of resistance ditch and theheight of resistance wall by response surface method. The result shows when the radius is10 mm, and the height is 0.5mm, both the filling and pre-forging load are in good condition.Finally,the real production was carried by the optimization process parameters to check the process parameters is correct and effective. Before optimization the crank arm appeared texture, and the micro-structure distributed not homogeneous. After optimization ferrite appeared along the grain boundaries, the micro-structure distribute homogeneous. It saves the cost of developing prices for hot forging of the crankshaft and reduces the time of try out and repair for forging die. At the same time brings reference for the same type of crankshaft for hot forging.