Application of tensile stress can alter material structure. Metals commonly undergo this type of mechanical deformation, which can be detrimental to its structural integrity and ultimately lead to failure. Subsequently, it becomes valuable to characterize mechanical deformation to prevent failures. We propose using second harmonic generation (SHG) to evaluate metal deformation. SHG is a viable option for such characterization, as it is a non-linear optical technique, used to study material surfaces. When a metal undergoes stress, dislocations occur, and grain boundaries are disrupted in a way that would become apparent at the metal's surface. These surface changes could then be detected through SHG methods. Additionally, SHG provides non-destructive evaluation (NDE) of materials, so characterization can occur without adding additional stress. We are using SHG to characterize steel samples before and after tensile stress. Stress is applied to steel samples at various rates and to different stages of deformation. Our aim is to find trends between the amount of tensile deformation applied to steel and the amount SHG signal detected. This would allow for a relatively accessible way to evaluate wear on metals, so that in industry, it can be determined when to replace parts before they break.