Failure Analysis on Fracture of Heavy Truck Leaf Spring

The fracture cause of heavy truck leaf spring was researched by macro examination, chemical compositions analysis, hardness test and metallographic examination. The results show that leaf spring excessive inverse arch-shaped for overload caused frictional contact between the plate spring bolt and the leaf spring and formation of erosion corrosion pits. Under the action of large alternating stress, the erosion corrosion pits became stress concentration positions and produced cracks. The cracks propagated gradually and finally resulted in fatigue fracture of the leaf spring. At last, measures of preventing leaf spring fracture accident were put forward.