Research On The Near-net Forging Technology Of S90 Heavy Crank Based On Free Forging Press

As the key component of marine engines,large marine crankshafts are known as the "heart" of engines,and their importance is evident.China has now become a major shipbuilding country and has a pivotal position in the global shipbuilding industry.However,at present,China's large-scale marine crankshafts still need to be imported from a large number of countries.Compared with Japan and South Korea,China's large-scale marine crankshafts have insufficient production capacity.Therefore,to achieve full domestic autonomy of large marine crankshafts is the only way for China to transform from a large shipbuilding country to a strong country.The key process of large-scale combined marine crankshaft manufacturing technology is the forging of the crankshaft.The quality of the crankshaft forgings not only directly affects the comprehensive performance of the crankshaft,but also affects its manufacturing cost,which in turn affects the survival of the enterprise.Improving the dimensional accuracy of cranks and forgings and reducing machining allowances have become one of the focuses of global crankshaft manufacturing technology competition.In this paper,the S90 large-scale crank is taken as the research object.According to the geometric characteristics of the large-scale crank,a three-step forging process of reverse extrusion,upsetting-reverse extrusion and pressure groove-reverse extrusion is proposed.The numerical simulation software FORGE is used as the analysis method,conducting a systematic study.This paper uses FORGE software to simulate the three forming processes respectively,and comprehensively evaluates the three forming processes from the aspects of dimensional accuracy,metal flow law,forging load size,forging temperature field distribution,and mold temperature.The results shows that the groove-reverse extrusion process has the best comprehensive performance.This paper makes a further research on the groove-reverse extrusion process was to obtain the best process parameters.In addition,based on the further study of the groove-reverse extrusion process,this paper designs a die for the groove-reverse extrusion process applied to the large free forging hydraulic pressfor the forging space and load requirements of the S90 large crank.In order to verify the proposed groove-reverse extrusion process,this paper conducted a crank experiment at a ratio of 1:5.The experimental results show that the forged S90 large-scale crank test specimen is qualified,and the numerical simulation results are basically consistent with the experimental tests.All the researches in the paper show that the pressure groove-reverse extrusion forming process of S90 large-scale crank is feasible and can be further tested in industrial production.