Comparative analysis of the fracture splitting deformation of the big end for C70S6, 36MnVS4 and 46MnVS5 connecting rods

Abstract

During the fracture splitting process of the connecting rod, the plastic deformation, especially the plastic deformation before cracking, not only causes the big end hole of the connecting rod to be out of roundness, but also increases the residual stress, affecting the assembly precision and even the service life of the connecting rod. In this paper, the mechanical properties of microalloyed steel C70S6, 36MnVS4 and 46MnVS5 connecting rod were determined by tensile test. The displacement field, plastic strain and the deformation principle of the big end before the crack initiation of the fracture splitting of the connecting rod were numerically simulated. The results show that the yield strength, tensile strength and plasticity index of the new medium carbon microalloyed steels 46MnVS5 and 36MnVS4 are significantly higher than those of C70S6. However, the C70S6 connecting rod has a long loading time before crack initiation, and the plastic deformation area of the groove root front is large and the strain is high. The plastic deformation of 36MnVS4 and 46MnVS5 connecting rods is small and the area is concentrated. Among the three, the 46MnVS5 connecting rod has the smallest deformation and the C70S6 connecting rod has the largest deformation.

Study on Characteristics of Ultrasound-Assisted Fracture Splitting for AISI 1045 Quenched and Tempered Steel

“…At present, with con-rod fracture splitting, it is easy to produce quality defects on the fracture surface and serious deformation of the crank bore in the fracture process [6], so it puts forward higher requirements for the materials used for fracture splitting, requiring the materials to have the characteristic of brittle fracture at room temperature, which seriously limits the selection of cracking materials [7]. At present, the main cracking materials are powder metallurgy, high carbon steel, nodular cast iron and malleable cast iron [8], but the cost of powder metallurgy and high carbon steel is high, and the mechanical properties of cast iron make it difficult to meet the requirements of the con-rod, which hinders the development of fracture splitting.…”