Research On The Forging Process Of Crank Used For Large Ship

This paper research on large marine crank forging which is produced by forge plant of Angang Heavy Machine Co.,Ltd.,combine with the production practices and the study of many scientific research works both at home and abroad,and also analyzes the reason that crank forging emerges thinning,pits and shrinkage defects in bending process.At home and abroad,a number of scholars have studied the bending of the crank forging,Through the research of other scholars,we find a common point,Many scholars hope to eliminate the surface quality defects of curved forgings by optimizing the shape of the blank or the size of the bending die before the bending process.By consult a lot of literature review combined with the practice of the production of nearly one hundred pieces of crank forging,under the existing production equipment level,It is difficult to rely on the optimization of bending process parameters to effectively eliminate bending defects.Finally,it is proposed that the surface defects can be eliminated by increasing the pulling length after bending to eliminate the surface defects,and then I changed the original process plan "bending-finishing" to"bending-drawing out-finishing".It is indicated that improving the forging process can effectively eliminate the bending defects of the finished products,greatly improve the surface quality of the crankshaft and reduce the forging allowance with the 26 pieces of crank forging production Process improvement.By increasing the length of the drawing process of the final heating numbers,the final heating numbers' forging ratio of the final forging is increased,which greatly reduces the probability of grain coarsening in the process of post forging heat treatment.