Cause of Fracture of Engine Block

The engine block bearing seat and corresponding bearing cover fractured during the development test of an automobile engine. The causes of fracture on engine block were analyzed by means of macroscopic observation, chemical composition analysis, metallographic examination and SEM analysis. The results show that the fatigue fracture of cylinder block bearing seat occurred firstly due to insufficient design structural strength under the action of cyclic stress, and then the bearing cover also fatigue fracture.