Thyssen Krupp Ag

Thyssenkrupp Steel Europe Ag

Christian Timma

Thomas Lostak

Stefan Krebs

Lisa Kisker

Sven Evers

Martin KÖRNER

A process for producing a steel product having a protective coating based on zinc and a tribologically active layer applied to the protective coating where the process includes providing a flat steel product provided with the protective coating, and applying an aqueous solution comprising ammonium sulfate and demineralized water to the protective coating of the steel product. The concentration of the ammonium sulfate based on the SOions is 0.01-5.7 mol/L, the pH of the aqueous solution is 4-6, and the near-surface reaction time between the aqueous solution and the protective coating is more than 0 seconds and not more than 5 seconds. After a drying operation conducted without preceding rinsing, a tribologically active layer consisting of ammonium zinc sulfate is formed atop the protective zinc coating. Also, a steel product having a protective coating based on zinc and a tribologically active layer of ammonium zinc sulfate.

Method for producing a steel product with a Zn coating and a tribologically active layer deposited on the coating, and a steel product produced according to said method

Coating materials with minimized lubricant demand enable optimized tribological conditions in forming flat steel products and are also unobjectionable in relation to their effects on the environment. With such coating materials, steel components can be produced by forming flat steel products in forming machines. For example, a tribologically-active layer may be produced on at least one surface of a flat steel product or a forming machine used to form the flat steel product, wherein the at least one surface comes into contact with the opposing component during forming. The tribologically-active layer may be formed by coating the at least one surface with a coating material from a group consisting of aluminum sulfate, ammonium sulfate, iron sulfate, and magnesium sulfate. The flat steel product may be inserted into the forming machine to be formed into the steel component.

Use of a sulphate, and method for producing a steel component by forming in a forming machine

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Duisburg, Germany

Christian Timma