| 摘要 |
PURPOSE:To manufacture stainless steel having excellent adhesion to coating material, by causing pitting corrosion on the surface of the stainless steel by the electrolysis in aqueous soln. of sodium chloride, then by providing a process for coarsening the pits formed by corrosion or for forming oxide film. CONSTITUTION:In the first step, DC electrolysis is performed in aqueous sodium chloride soln. 0.02-2.0wt% concn. at 20-100mA/cm<2> current density using stainless steel as an anode. Because pH increases in the first step, DC electrolysis is performed in the second step in aqueous soln. 0.02-2.0wt% sodium chloride concn. and 0.03-3.0wt% hydrochloric acid concn. at 20-100mA/cm<2> current density using the stainless steel as an anode. Platinum is used for the cathode. The parts having not undergone pitting corrosion are subjected to surface treatment with corroding fluid such as hydrochloric acid etc., or to surface grinding with abradant, or oxide film is formed on the parts by heating in the air or in combustion gas at 500-1,000 deg.C temp. Hereby stainless steel having excellent adhesion to coating material is manufactured. |
