<b>To Study the Effect of Stress Concentration Factor on Mild Steel Due to Heat Treatment</b> The present work is to study the effect of various types of heat treatment processes on stress concentration factor Kt of a plate with a circular hole subjected to a uniform loading. Finite Element Analysis using ABAQUS 6.13 1 has been done in order to calculate, Kt for rectangular plates with holes of different diameters. Stress Strain diagrams are generated from standard tensile specimens ASTM E8 with Universal Testing machine HEICO , before and after various types of heat treatment process. Young’s Modulus, Poisson’s Ratio and the Plastic strain verses Stress are calculated from the Stress strain diagram and feed as an Input parameter for the FEA analysis. The results shows that the value of Kt for quenching has a higher value in comparison to room temperature mild steel specimen and the value of Kt for normalizing and annealing show a lower value in comparison to room temperature mild steel specimen. Stress Concentration factor Kt , Heat treatment, Tensile Test, Finite Element Analysis 257-261 Issue-6 Volume-1 Aman Roy | Ranik Das | Pratick Chand Samanta | K. Bhattacharyya