Hossein Tahmasebi Manesh - Malek Ashtar University of Technology, ShahinShahr,Iran
Alireza Nasresfahani - Malek Ashtar University of Technology, ShahinShahr,Iran

P۴۶۰NH micro-alloy steel is used in applications such as boilers and pressure vessels. Different welding processes and filler metal can be used to for welding of this steel. In this study, manual arc welding process (SMAW) with E۸۰۱۸-G electrode and tungsten arc welding process with argon shielded gas (TIG) with ER۸۰S-G welding wire were used and to obtain optimal welding parameters, according to ASME IX welding standard was performed. Then, by sampling from the welding section, the corrosion behavior of the heat affected zone, weld bead and base metal was investigated separately using Tafel polarization test in ۳.۵% NaCl solution. Evaluation of corrosion behavior of different regions also showed that in manual arc welding with shielded electrode ۸۰E۸۰۱۸-G, theheat affected zone has the highest corrosion potential (۰.۶۵۲ v) and the lowest corrosion current density (۱.۷۵ - ۱۰-۵ A/cm۲). This is while the base metal with the lowest corrosion potential (۰.۶۹۳ v) and the highest corrosion current density (۱.۲ × ۱۰-۵ A/cm۲) is relative to the weld metal and the heat affected zone. In tungsten arc welding with argon shielding gas with ER۸۰S-G welding wire, the weld metal has the highest corrosion potential (۰.۶۸۹ volts) and the lowest corrosion current density (۵.۴× ۱۰-۵ A/cm۲). And the base metal with corrosion potential (۰.۶۹۳ V) has the highest corrosion current density (۱.۲ × ۱۰-۵ A/cm۲) compared to the weld metal and the heat affected zone. In general, by examining the corrosion resistance of two welded parts, it can be stated that the manual arc welding process with E۸۰۱۸-G electrode has better corrosion resistance than the tungsten arc welding process with argon shielding gas with ER۸۰S-G welding wire.

P۴۶۰NH steel, E۸۰۱۸-G electrode, corrosion potential, corrosion current density, hardness, tafel polarization test.