Fracture Causes of Transmission Mounting Arm

When the test car passed a pit during the road test, a transmission mounting arm was fractured due to the impact load. The fracture causes of the transmission mounting arm were analyzed by means of macro analysis, fracture analysis, metallographic examination, chemical composition analysis, hardness test and inspection of the same batch of parts. The results show that the fracture of the transmission mounting arm was due to the existence of hot cracks inside the arm. The hot cracks were related to the increase of mold temperature, the absence of mold release agent on the back of core mold and the insufficient cooling of casting during demoulding.