Experimental and computational failure analysis of TR upset-bending equipment for heavy crankshaft with continuous grain flow

The objective is to analyze the fracture of TR upset-bending equipment for the heavy crankshaft with continuous grain flow, in which the die base was broken in the first service when the crankshaft’s formation was changed as the closed-die forging. The chemical composition, mechanical properties and the hardness of the die base’s material were examined in comparison with the design requirement. The metallurgical properties inspection and SEM observation were conducted to seek the failure reason of the die base. At the same time, the computational failure analysis was also carried out. The heavy crankshaft forging process was simulated by software DEFORM-3D, through which the forming load was obtained. The forging simulation result was introduced to software I-dears as the boundary condition of the structural strength analysis for upset-bending equipment. The field of stress and deformation in the die base was calculated and the maximum load capacity was estimated. Structural optimization was performed in the high risk region of the die base, by which the stress magnitude was decreased and the load capacity was improved. This research achievement will be helpful to the design of heavy crankshaft’s forging process and die structure optimization.