Sensitization and corrosion of 409M ferritic stainless steel by different welding processes

Abstract

The aim of this research work was to analyze the sensitization due to the effect of welding (Shielded Metal Arc Welding, Gas Tungsten Arc Welding & Gas Metal Arc Welding) heat in heat affected zone area in terms of metallurgical properties, mechanical properties and corrosion of base metal comparatively. Also the effect of different chemicals / acidic environments on tensile properties was investigated. The plates of 3 mm thickness of 409M Ferritic Stainless Steel welded at constant current of 90A by three different welding processes with the same filler metal. The microstructure observation was made after Marble reagent chemical etched. Then tensile properties were investigated and comparative analysis done between the tensile properties i.e. before and after the chemical exposure given to it with the parent metal. After completion of experimental work it is found that SMAW, GMAW and GTAW have affected the microstructure of 409M Ferritic Stainless Steel. Due to the acidic environments/ Chemical exposures the strength and ductility of the metal affects. But comparatively GTAW has shown better process than GMAW and SMAW for welding of 409M Ferritic Stainless Steel. It should be used with caution in sulphuric acid environments than chloride environments to resist corrosion.