Failure analysis of upset bending equipment for a heavy crankshaft with continuous grain flow

A failure investigation is conducted on the upset bending equipment of a heavy crankshaft with continuous grain flow which is broken in the first use after the crankshaft flange is modified to deform in the die cavity. The forging process of the heavy crankshaft is simulated using the DEFORM 3D software, through which the forming load and die filling are calculated. Using the I Dears software, the structural strength calculation for the upset bending equipment is performed. The stress field and displacement in the equipment are obtained. The failure analysis of the die base is accomplished. The analysis results show that the practical crack location and orientation in the die base are consistent with those in the structural strength calculation.