The multi-ram forging process of railway clamp under a certain kind of preformed blank was designed, and samples were gained by industrial experiment. It was studied the causes of forging defects, such as folding, burr in railway clamp's multi-ram forging process. By establishing a finite element model and choosing the proper simulation parameters, the numerical simulation of the forming process was carried out based on Deform, and the metal flow rule in the forming process was researched with the aid of point tracing function of Deform. The result shows that the fundamental reason of burr is sharply increase clamp force of the top die caused by the unreasonable die structure, and the increasing amount can up to 3776.28 kN, The forming die cannot be clamped because of deficiency of equipment tonnage. Critical reduction of folding defect is 14 mm, however, 9 mm reduction in the industrial experiment cannot cause folding defects. The main reason of sample folding defects depends on the small assembly clearance between the top die and the hot preformed blank, which results in interference at the beginning of the forging process. According to the analysis,the solving measures were proposed and the well-formed samples were gained under simulation condition, the rationality of preformed blank shape and feasibility of the multi-ram forging process were verified.
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