دانلود رایگان مقاله تحلیل شکستگی شکست ارتباط فولاد ضد زنگ 4Cr13

Abstract

In this study, the fracture failure of the 4Cr13 stainless steel linkage components in circuit breakers was studied. The microstructure and morphology of fracture surface were observed by scanning electron microscopy and optical microscopy. A micro-Vickers tester measured the hardness of the components. The tensile strength and strain of the components were determined by a universal testing machine. The results show that fracture failure mode was quasi-cleavage fracture, and some dimples and edges of cleavage were present on the fracture surface. The substandard sample exhibited higher hardness than the standard sample. The high hardness could cause the strong rigidity and less toughness, which was not helpful to bend the samples to form hook structure. The heat treatment influenced the mechanical properties of the 4Cr13 components. With increasing the tempering temperature, the hardness of the component was decreased when the quenching temperature was kept stable.

4. Conclusions and recommendations

(1) The fracture surface consisted of cleavage terrace with tore edge, dimple and river pattern. The failure mode of 4Cr13 component was the quasi-cleavage fracture. (2) Compared with the standard sample, the substandard sample exhibited a high hardness, which could cause the strong rigidity, but resulting in the less toughness. (3) The heat treatment process and other manufacturing processes has a significant effect on the microstructure and mechanical properties of the samples. With increasing the tempering temperature, the hardness of the component was decreased when the quenching temperature was kept stable. During heat treatment and manufacturing processing for 4Cr13 linkage component, the microcrack was induced sensitivity, finally resulting in the fracture failure of the components under overloading condition. The prevention of 4Cr13 components should control and check the raw material, which could affect the properties of the components. Furthermore, we should control the several special processes, such as the heat treatment processing, annealing, quenching and tempering, and observe the surface of the bending parts after twice bendings, and even plan to test the hardness of the components and other detection technologies. Last, the microcracks should be carefully checked again in each special process. Avoid mechanical damage to the surface, such as scratches and dents, because they can act as crack initiation sites. It was carefully adapted to make installation, operation or maintenance, which was recommended as necessary corrective actions for failure prevention.