CORROSION RESISTANCE OF COLD-ROLLED AISI 301 STAINLESS STEEL

The performed investigations concerned on the effect of cold rolling on the corrosion behavior and microstructure of austenitic AISI 301 stainless steel. Samples of steel strip were cold-rolled within the degree of deformation 30%, 50% and 80%. The corrosion resistance test was examined using gravimetric and potentiodynamic method. Corrosion tests were conducted in acidic and alkaline corrosive environments. A light microscope and a scanning electron microscope were used to observe the surface morphology of the samples after corrosion testing. Corrosion tests by gravimetric method showed that investigated steel is not resistant to corrosion in 0.5N H₂SO₄ solution, while no significant weight loss was observed in artificial seawater solution (0.5N NaCl). Based on potentiodynamic tests carried out in 0.5N NaCl solution, it was found that the pitting corrosion resistance of the tested cold-rolled steel AISI 301 decreases with an increase in the degree of plastic deformation in the range of 30% to 80%. However, a decrease in the corrosion potential and an increase in the current density were observed on the polarisation curves. The propensity of the steel to initiation and propagation pitting was found to increase both with increasing degree of deformation and the associated increase in the volume proportion of martensite-α' in the material structure. The occurring of martensite-α’ in the investigated steel was confirmed by X-ray methods.