Effects Of Arc Quenching On The Surface Hardness Of Medium Carbon Steel

Abstract

This work investigates the surface hardness after arc quenching S45C steel with a convex surface, including arc length, current intensity, travel speed, gas flow rate, and the pulse duration. The surface hardness is mostly determined by the intensity of the current. Interestingly, the convex surface shows an impressive 108% increasing from its initial hardness of 182 HV. Increased heat input at high current intensity may be the cause of the overheating and melting phenomena as well as the decreased hardness. Surface hardness generally increases with increases in gas flow rate, resulting from an enhanced gas cooling rate. Similar to the gas flow rate, surface hardness rises with TIG gun travel speed. In addition, the convex surface hardness's Taguchi prediction value is 359.6 HV. The ideal parameters are 90 A for the current intensity, 2.5 mm for the arc length, 12 l/min for the gas flow rate, 200 mm/min for the travel speed, and 0.7 s for the pulse duration. In addition, 3D surface plots were also used to evaluate the degree of interaction between parameters with each other. For the S45C convex surface, the maximum case depth of the arc quenching is 3500 µm. The hardened area, the heat-affected area, and the base substrate are the three regions of the arc quenching sample's microstructure.