Effects of H2O2 and temperature on electrolytic pickling of austenitic stainless steel 304L in Na2SO4 solution

The effects of H2O2 solution addition and temperature on electrolytic pickling via an Na2SO4 solution to eliminate metal oxide layers from annealed 304L stainless steel were investigated by means of polarization. The experimental conditions involved a pure 190 kg × m-3 Na2SO4 solution and a mixture of 190 kg × m-3 Na2SO4 + 10 kg × m-3 H2O2 at 298, 318 and 333 K and pH 4. It was found that the addition of a 10 kg × m-3 H2O2 solution to a 190 kg × m-3 Na2SO4 solution and an increase in temperature resulted in a decrease in the passive region of the polarization curves. Results from SEM images, XRD patterns and root-mean-square roughness showed that the surface of the annealed 304L stainless steel was smoother and fewer remaining oxide scales were found when pickling in 190 kg × m-3 Na2SO4 + 10 kg × m-3 H2O2 solution. However, no effects on the pickling time at 298, 318 and 333 K through the addition of 10 kg × m-3 H2O2 solution to the 190 kg × m-3 Na2SO4 solution and the temperature were observed.

Effects of H2O2 and temperature on electrolytic pickling of austenitic stainless steel 304L in Na2SO4 solution

The effects of H2O2 solution addition and temperature on electrolytic pickling via Na2SO4 solution to eliminate the metal oxide layers of an annealed 304L stainless steel were investigated by polarization technique. The experimental conditions involved a pure 190 kg × m-3 Na2SO4 solution and a mixture of 190 kg × m-3 Na2SO4+ 10 kg × m-3 H2O2at 298, 318 and 333 K and pH 4. It was found that the addition of a 10 kg × m-3 H2O2 solution in 190 kg × m-3 Na2SO4 solution and an increase in temperature resulted in a decrease in the passive region of the polarization curves. The results from the SEM images, the XRD patterns and root-meansquare roughness showed that the surface of the annealed 304L stainless steel was smoother and fewer remaining oxide scales was found when pickling in 190 kg × m-3 Na2SO4 + 10 kg × m-3 H2O2 solution. However, no effects of the addition of 10 kg × m-3 H2O2 solution in 190 kg × m-3 Na2SO4 solution and temperature on pickling time at 298, 318 and 333 K were observed.