Fracture-Splitting Processing Performance Study and Comparison of the C70S6 and 36MnVS4 Connecting Rods

36MnVS4 is a new connecting-rod fracture-splitting material. To explore why it has a high fracture- splitting defective index, this article simulated the fracture-splitting process of connecting rods. Comparing 36MnVS4 with C70S6, this article analyzed the stress-strain state of the groove roots, the position of crack initiation, the plastic deformation distribution of the fracture surface, and the splitting force changes in fracture splitting process. Results show that the crack initiation position of the 36MnVS4 connecting rod is relatively more scattered and random, and the crack starting point of the C70S6 connecting rod is more unique. Compared with the C70S6 connecting rod, the 36MnVS4 connecting rod has an earlier crack initiation time and smaller fracture-splitting force. Therefore, the 36MnVS4 has higher gap sensitivity and its fracture surface is more prone to tear. Through test validation, it is determined that the fracture surface of the 36MnVS4 connecting rod has some deformation, steps, and tear, while the fracture surface of the C70S6 is more flat. The fracture surface quality of the C70S6 connecting rod is relatively higher. Experimental results are consistent with the finite element, and it proves the rationality of the selection of fracture criteria.