An Assessment of the Microstructure and Mechanical Properties of 0.26% Low Carbon Steel under Different Cooling Media: Analysis by one-way ANOVA

This study reports the effect of heat treatment on the microstructure and mechanical properties of 0.26% low carbon steel at 850oC using different cooling media. Annealing, normalizing and age-hardening heat-treatments were used for the experimental work. Hardness tests, fatigue tests, compression tests and metallography were carried out on the heat-treated and control samples. The results were further analyzed using the one-way ANOVA test. The results obtained showed significant differences in the microstructure and mechanical properties of the different heat-treated samples. The hardness profile determined using a Brinell ball indenter showed decrease in hardness of the heat-treated samples when compared with the control. Normalizing heat-treatment yielded a microstructure of better quality than annealing and age-hardening. A higher compressive strength of 155.97MPa and 151.52MPa was obtained with normalizing and annealing heat treatments respectively in comparison to agehardening (149.93MPa), and the control test (150.56MPa). Improved fatigue strength was also obtained with annealing heat treatment. ANOVA test confirmed the results at 90% confidence and further showed that there was significant difference between the four test condition