| 摘要 |
PURPOSE:To remove oxide scale on the surface of stainless steel in a short time by cracking the scale, subjecting the steel to electrolytic treatment in an aqueous neutral salt soln., and immersing the steel in an aqueous sulfuric acid soln. and an aqueous mixed acid soln. contg. nitric acid and hydrofluoric acid in succession. CONSTITUTION:Oxide scale on the surface of Cr or Cr-Ni stainless steel is cracked or broken by bending, stretching, shot blasting or other method, and the steel is subjected to electrolytic treatment in an aqueous soln. of a neutral salt such as Na2SO4. The steel is then immersed in an aqueous sulfuric acid soln. having 100-300g/l concn. of sulfuric acid at 70-95 deg.C, and it is further immersed in an aqueous mixed acid soln. contg. 150g/l nitric acid and 30g/l hydrofluoric acid. The oxide scale on the surface of the stainless steel is dissolved and removed in a short time. |
