Experimental analysis of mechanical behaviour and residual stresses of EN-36C alloy steel with and without tempering

The intense demands of nickel chromium case hardened steel (EN-36C) alloy steel in different engineering applications are increasing day by day due to its cheap and easy availability. The effect of different stages of tempering on EN-36C alloy steel has been carried out to check the mechanical behavioural, microstructural properties and residual stresses in the present work. The effect of tempering on response variables viz., material removal rate, surface roughness, tool tip temperature and residual stresses are evaluated. The cosα method is used to measure the residual stresses in the specimen using two-dimensional detectors such as imaging plates. Further, the influence of tempering on mechanical properties such as tensile strength, hardness, toughness and percentage elongation has been observed. Experimental results depicted that the ductility and toughness are improved without significant change in hardness in the specimen tempered at 500°C. The mechanical properties of specimens tempered at 500°C are found to be a tensile strength of 680.42 MPa, hardness 92 Rockwell hardness of scale B and toughness 187 J. The maximum value of material removal rate (12596.80 mm 3 /min), minimum tool tip temperature (61.33°C), average surface roughness ( R a = 1.93, R q = 2.36, R z = 10.30) and lowest residual stress 217 MPa are observed in the specimens tempered at 500°C.