ACID PICKLING OF MARTENSITIC STEEL FREE

A process according to claim 1, wherein the martensitic or ferritic stainless steel is in a form selected from the group consisting of wires, tubes and rods.ĩ. A process according to claim 1, wherein the pickling solution is moved about relative to the stainless steel during said contacting.Ĩ. A process according to claim 1, additionally comprising adjusting the redox potential by adding to the pickling solution at least one reagent selected from the group consisting of hydrogen peroxide and hydrogen peroxide-releasing substances.ħ. A process according to claim 1, additionally comprising adjusting the redox potential by taking one or more of the following actions: a) adding a reagent to the pickling solution which is able to oxidize Fe(II) ions in the pickling solution to Fe(III) ions b) catalytically oxidizing the pickling solution with an oxygen-containing gas using a homogeneous or heterogeneous oxidation catalyst c) electrochemically oxidizing the pickling solution.Ħ. with a platinum electrode and relative to an Ag/AgCl reference electrode, of 150 to 235 mV.ĥ. A process according to claim 1, wherein the pickling solution has a redox potential, measured at 25° C. with a platinum electrode and relative to an Ag/AgCl reference electrode, of 100 to 229 mV.Ĥ.

ACID PICKLING OF MARTENSITIC STEEL FREE

A process according to claim 1, wherein the pickling solution comprises 55 to 75 g/l of free sulfuric acid.ģ. with a platinum electrode and relative to an Ag/AgCl reference electrode, of 100 to 240 mV.Ģ. A process for pickling martensitic or ferritic stainless steel, said process comprising contacting the martensitic or ferritic stainless steel with a pickling solution comprising: 5 to 13.5 g/l of Fe(III) ions, an amount of Fe(II) such that the total amount of Fe(III)+Fe(II) is not above a limiting value of 110 g/l, 50 to 120 g/l of free sulfuric acid and 5 to 40 g/l of free HF at a temperature in the range 15 to 29° C., for a time of 5 to 25 minutes, said pickling solution having a redox potential, measured at 25° C. Method for continuous pickling of steel materials on a treatment lineġ. Process for pickling a piece of steel and in particular a sheet strip of stainless steel Process for stainless steel pickling and passivation without using nitric acid Steel pickling process in which the oxidation of the ferrous ion formed is carried out electrolytically

Hydrogen peroxide pickling scheme for stainless steel grades

Process for pickling stainless steel in the absence of nitric acid and in the presence of chloride ions Process for electrolytic pickling using nitric acid-free solutions Continous electrolytic pickling method for metallic products using alternate current supplied cellsīrightening/passivating metal surfaces without hazard from emissions of oxides of nitrogen

Acid pickling of martensitic steel