AbstractThin section ferritic stainless steels (AISI 430) welded by autogenous gas tungsten arc welding with low heat input conditions were characterised for the microstructural features, hardness and corrosion behaviour. Development of very coarse grained heat affected zones (HAZ) was observed even with the low heat input level applied. The weld metal was found to be over matched in terms of mechanical properties (hardness and tensile strength). Both the parent material and the weld metal/HAZ region have shown poor corrosion resistance in neutral and acidic chloride solutions. The corrosion resistance of these regions was found to be adversely influenced with increasing chloride level in the test electrolyte. The weld metal/HAZ region of this weldment has shown a higher susceptibility to localised corrosion damage compared to the parent alloy in both the neutral and acidic chloride solutions.