Abstract
The failure analysis of induction hardened injector body was carried out to identify surface defects. Producer revealed the defects using nondestructive testing method and requested a detailed analysis to determine the cause of their origin. Metallographic and fracture analysis were performed to study the material microstructure and fracture surface. Metallographic analysis proved the existence of a crack, initiated from the front face of component. Microstructure of the crack vicinity as well as hardness was significantly different with increasing distance from the face of component. Microstructure near the front face consisted of coarse martensite, while finer martensitic structure was observed with increasing distance from the front face. Hardness showed decreasing tendency with increasing distance from the front face. Fractographic analysis revealed the intergranular cleavage fracture near the front face of component. With increasing distance from the front face, quasicleavage fracture was observed with increasing areal fraction characterized by ductile fracture. Due to significant difference in microstructure and corresponding difference in hardness within a small area of component can be assumed, that the crack initiation occurred due to internal stress of the material caused by heat treatment. It is necessary to optimize the parameters of induction hardening process with respect to the different thicknesses of the product.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call