ABSTRACT Engineering materials, mostly steel, are heat treated under controlled sequence of heating and
cooling to alter their physical and mechanical properties to meet desired engineering
applications. In this study, the effect of heat treatment (annealing, normalising, hardening, and
tempering) on the microstructure and some selected mechanical properties of NST 37-2 steel
were studied. Sample of steel was purchased from local market and the spectrometry analysis
was carried out. The steel samples were heat treated in an electric furnace at different
temperature levels and holding times; and then cooled in different media. The mechanical
properties (tensile yield strength, ultimate tensile strength, Young’s modulus, percentage
reduction, percentage elongation, toughness 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 NST 37-2 steel can be changed and improved by various heat treatments for a
particular application. It was also found that the annealed samples with mainly ferrite structure
gave the lowest tensile strength and hardness value and highest ductility and toughness value
while hardened sample which comprise martensite gave the highest tensile strength and hardness
value and lowest ductility and toughness value.
Cite this paper
D. Fadare, T. Fadara and O. Akanbi, "Effect of Heat Treatment on Mechanical Properties and Microstructure of NST 37-2 Steel," Journal of Minerals and Materials Characterization and Engineering, Vol. 10 No. 3, 2011, pp. 299-308. doi: 10.4236/jmmce.2011.103020.
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