Arcelormittal

Arcelormittal France

Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Florence Bertrand

Jean-Michel Mataigne

Didier Dauchelle

David Zapico Alvarez

Joris Giroux

Didier Huin

Hubert Saint-Raymond

A galvannealed steel sheet obtainable by a method including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas, a hot-dip galvanizing and an alloying treatment, wherein the zinc coating is alloyed through diffusion of the iron from the steel sheet such that the zinc coating includes from 5 to 15% by weight of Fe, oxides including FeO, Mn2SiO4 and MnO, the balance being zinc, the steel sheet including internal oxides including FeO, Mn2SiO4 and MnO in the steel sheet.

Galvannealed steel sheet

The present invention relates to a method for the manufacture of a hot-dip coated steel sheet coated with a zinc or an aluminum based coating including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas and a hot-dip coating; the hot dip coated steel sheet and the use of the hot-dip coated steel sheet.

Hot-dip coated steel sheet

A method for the manufacture of a galvannealed steel sheet including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas, a hot-dip galvanizing and an alloying treatment; the galvannealed steel sheet and the use of the galvannealed steel sheet.

A steel part includes a steel sheet substrate and a coating on at least one surface of the steel sheet substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The steel sheet substrate and the coating have at least one deformation. An outer surface of the coating has a waviness Waof less than or equal to 0.43 &#x3bc;m.

Method for manufacturing a metal sheet with a ZnAl coating and with optimized wiping, corresponding metal sheet, part and vehicle

The present invention provides a method for manufacturing a metal sheet. In this method, at least one of the following equations is satisfied: wherein:

The present invention provides a deformed part created by forming a coated metal sheet into a part, the coated metal sheet comprising a steel substrate, at least one face of which is coated with a metal coating deposited by dipping the substrate in a bath, said coating comprising between 0.2 and 0.7% by weight of Al, the remainder of the metal coating being Zn and inevitable impurities, wherein an outer surface of a metal coating of the deformed part has a waviness Wa0.8 of less than or equal to 0.43 &#x3bc;m.

Deformed part and vehicle

The present invention provides a method for manufacturing a metal sheet. In this method, at least one of the following equations is satisfied: 

Metal sheet with a ZnAl coating

The invention deals with a hot-dip galvanized or galvannealed steel sheet wherein, the composition of the steel sheet comprises, by weight: 0.01&#x2266;C&#x2266;0.22%, 0.50&#x2266;Mn&#x2266;2.0%, 0.2&#x2266;Si&#x2266;3.0%, 0.005&#x2266;Al&#x2266;2.0%, Mo&#x3c;1.0%, Cr&#x2266;1.0%, P&#x3c;0.02%, Ti&#x2266;0.20%, V&#x2266;0.40%, Ni&#x2266;1.0%, Nb&#x2266;0.20%, the balance of the composition being iron and unavoidable impurities resulting from the smelting, and the steel sheet comprises a layer of an internal nitride of at least one type of nitride selected from a Si nitride, Mn nitride, Al nitride, complex nitride comprising Si and Mn, or Al and Si, or Al and Mn, or complex nitride comprising Si, Mn and Al, said steel sheet comprising no further outer layer of iron nitride.

Galvanized or galvannealed silicon steel

The invention deals with a process for manufacturing a hot-dip galvanized or galvannealed steel sheet having a TRIP microstructure, said process comprising the steps consisting in: -providing a steel sheet whose composition comprises, by weight: 0.01&#x2266;C&#x2266;0.22%, 0.50&#x2266;Mn&#x2266;2.0%, 0.2&#x2266;Si&#x2266;2.0%, 0.005&#x2266;Al&#x2266;2.0%, Mo&#x3c;1.0%, Cr&#x2266;1.0%, P&#x3c;0.02%, Ti&#x2266;0.20%, V&#x2266;0.40%, Ni&#x2266;1.0%, Nb&#x2266;0.20%, the balance of the composition being iron and unavoidable impurities resulting from the smelting, -oxidizing said steel sheet in a direct flame furnace where the atmosphere comprises air and fuel with an air-to-fuel ratio between 0.80 and 0.95, so that a layer of iron oxide having a thickness from 0.05 to 0.2 &#x3bc;m is formed on the surface of the steel sheet, and an internal oxide of Si and/or Mn and/or Al is formed, -reducing said oxidized steel sheet, at a reduction rate from 0.001 to 0.010 &#x3bc;m/s, in order to achieve a reduction of the layer of iron oxide, -hot-dip galvanising said reduced steel sheet to form a zinc-coated steel sheet, and -optionally, subjecting said hot-dip coated steel sheet to an alloying treatment to form a galvannealed steel sheet.

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Scy Chazelles, France

Florence Bertrand