Author : Ashish Thakur and Gebre-egziabher Aregawi

This paper presents effect of heat treatment (annealed, quench hardened, and tempered) on mechanical properties and microstructureof the rear trailing arm case study at Mesfin Industrial Engineering PLC, Ethiopia. The samples were heat treated in muffle furnace in Mekelle University, Heat Treatment Lab at different temperature levels and holding times; and then cooled in different media. The mechanical properties (tensile yield strength, ultimate tensile strength, percentage reduction, and percentage elongation), bending, impact and hardness of the treated and untreated samples were determined using standard methods and the microstructure of the samples was examined using metallographic microscope equipped with camera.Results showed that the mechanical properties of ST 37-2 steel can be improved by various heat treatments for a particular application.The micrograph revealed that the microstructure of tempered specimen consisted of a number of appreciable carbide particles precipitated out from the matrix, which indicated that the precipitate carbide particles decomposed by a process of solution in ferrite matrix. It was also found that the annealed samples with mainly ferrite structuregave the lowest tensile strength hardness and highest ductility while hardened sample which comprise martensite gave the highest tensile strength and hardness and lowest ductility.

Keywords: Failure analysis, rear trailing arm, microstructure, heat treatment

Article published in International Journal of Current Engineering and Technology, Vol.9, No.1 (Jan/Feb 2019)