EFFECT OF HEAT TREATMENT ON THE CORROSION RESISTANCE OF AISI 420 MARTENSITIC STAINLESS STEEL: A COMPUTATIONAL AND EXPERIMENTAL STUDY

This study investigates the effect of heat treatment on the corrosion behavior of AISI 420 martensitic stainless steel using a combination of numerical simulation and electrochemical experiments. The specimens were austenitized at 1050°C for 1 h, oil-quenched, and tempered at temperatures ranging from 250°C to 650°C for 2 h. The electrical conductivity of the steel was measured and used as an input parameter in an electrochemical model developed using COMSOL Multiphysics to simulate the polarization curves. Electrochemical impedance spectroscopy (EIS) was employed to further characterize the interfacial charge-transfer behavior. The EIS results revealed that the charge-transfer resistance (Rct) varied significantly with heat-treatment conditions, reaching a maximum of 378 Ω at 350°C and decreasing to 46.3 Ω at 650°C. The simulation and experimental results exhibited consistent trends, particularly regarding the deterioration of corrosion resistance at higher tempering temperatures. These findings confirm that the combination of COMSOL-based potentiodynamic polarization simulation and EIS analysis is an effective approach for evaluating the influence of heat treatment on the corrosion behavior of AISI 420 martensitic stainless steel.