Henkel Ag & Company, Kgaa

Other

Henkel Kommanditgesellschaft Auf Aktien

Henkel Kgaa

Mauro Rigamonti

Paolo Giordani

Valentino Gasparetto

Dario Negri

Hans Clodt

Ioannis Demertzis

Stefano Sfolcini

Reinhard Seidel

Roberto Galli

Luigi Dante Madonini

Paolo Gamboggi

This invention relates to a composition for the brightening and/or passivating of stainless steel after pickling. The invention is based on the discovery that the presence of organic compounds containing multiple hydroxyl groups with at least 3, but not more than 8 carbon atoms as a further ingredient of passivating and brightening solution significantly increases the desmutting performance of pickled stainless steel surfaces. The compositions of the invention are especially useful for the passivating and brightening of stainless steel grades being alloyed with sulfur. The invention thus further encompasses a passivating and brightening process for pickled stainless steel surfaces wherein the stainless steel is alloyed with at least 0.10 at.-% of sulfur.

Brightening and passivation of stainless steel surfaces

The present invention relates to the use of an alkaline, aqueous coating composition for coating of zinc or zinc alloy coated steel substrates, comprising one or more alkaline sulfates, and one or more alkaline carbonates, wherein the pH of the composition ranges from 9-12. The present invention also defines a method for the non-reactive coating of zinc or zinc alloy coated steel substrates by use of said compositions and further relates to the application of said method as a surrogate for pre-phosphating of zinc or zinc alloy coated steel substrates in industrial applications.

Dry lubricant for zinc coated steel

The present invention relates to an acidic aqueous solution suitable for the pickling of stainless steel grades that comprises accelerators based on water soluble inorganic compounds comprising at least one nitrogen atom in an oxidation state in the range of &#x2212;2 to &#x2212;&#x2153;. The present invention further encompasses a process for the pickling of stainless steel that makes use of a pickling solution comprising the above-mentioned accelerators.

Use of nitrogen compounds in the pickling of stainless steel

The use of complex fluoride ions of elements of groups 4, 13, or 14 of the periodic table of the chemical elements (preferably selected from complex fluoride ions of the elements B, Si, Ti, and Zr) in concentrations from 30 t 500 millimoles per liter in process solutions for pickling steel or for bleaching and/or passivating pickled surfaces of stainless steel; a process solution for pickling steel or bleaching and/or passivating pickled surfaces of stainless steel comprising: a) one or more strong acids, b) one or more oxidizing agents in the bleaching/passisvating process, c) complex fluoride ions of elements of groups 4, 13 or 14 of the periodic table of the chemical elements in concentrations from 50 to 500 mmoles per liter; replenisher or concentrate containing a combination of active substances thereof; a process for pickling steel or for brightening and/or passivating of pickled surfaces of stainless steel, wherein the surfaces are brought into contact with such a process solution.

Pickling or brightening/passivating solution and process for steel and stainless steel

A process for pickling martensitic or ferritic stainless steel, preferably in the form of wires, tubes or rods, wherein the stainless steel is placed in contact with a pickling solution which has a temperature in the range 15 to 29&#xb0; C. and contains 50 to 120 g/l of free sulfuric acid, 5 to 40 g/l of free HF and 5 to 40 g/l of Fe(III) ions. Such pickling may be incorporated into a sequential process, wherein the stainless steel is a) subjected to a treatment during which the oxidic coating is applied, preferably sand-blasting or metal-blasting, treatment with a molten salt or treatment with an aqueous permanganate/alkali metal hydroxide solution, b) pickled in accordance with the aforedescribed process, and c) post-treated with a passivating solution.

Process for pickling martensitic or ferritic stainless steel

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Opera, Italy

Mauro Rigamonti