Electrochemical Evaluation of AISI 420 Steel after Several Heat Treatments

The paper deals with the study of the electrochemical behavior of a heat treated AISI 420 martensitic stainless steel, usually used on surgical instruments.According to the alloy composition we designed the heat treatment procedures with specific parameters in order to enhance the properties of the alloy.The heat treatments involved are: Annealing at 770 • C with maintaining 20 min followed by slow cooling in furnace; martensitic quenching at 1000 • C with maintaining 30 min followed by rapid cooling in water, and high tempering at 700 • C with maintaining for 60 min followed by free cooling in open air.The characterization of electrochemical behavior of AISI 420 steel was done in a 0.5 M NaCl aqueous solution.The study concluded that by applying high tempering a decrease of hardness and an increase of mechanical properties is obtained.Also high tempering induces a better corrosion resistance for our studied alloy.