Arcelormittal

Gunhild Föjer

Luc Diez

Jean-Christophe Hell

Manel Ben Saad

Michel Soler

Clémence Filou

A process for the manufacture of a pre-painted sheet. The process includes supplying a steel substrate, depositing a metallic coating on at least one face by hot-dipping of the substrate in a bath including 4.4% to 5.25% by weight aluminum and 0.3% to 0.56% by weight magnesium. The rest of the bath includes exclusively zinc, unavoidable impurities resulting from the process and optionally one or more additional elements including Si, Ti, Ca, Mn, La, Ce and Bi. The content by weight of each additional element in the metallic coating is less than 0.3% and the presence of nickel is excluded. The process further includes solidifying the metallic coating, surface preparation of the metallic coating and painting of the metallic coating. The present invention further provides a pre-painted sheet.

ZnAlMg-coated metal sheet with improved flexibility and corresponding manufacturing process

A method for manufacturing a high-strength sheet having improved formability and ductility accord which the chemical composition of the steel contains, in percent by weight: 0.25%&#x3c;C&#x2264;0.4% 2.3%&#x2264;Mn&#x2264;3.5% 2.3%&#x2264;Si&#x2264;3% Al&#x2264;0.040% the remainder being Fe and unavoidable impurities, the method comprising the steps of annealing a rolled sheet made of said steel by soaking it at an annealing temperature AT higher than the Actransformation point of the steel, quenching the sheet by cooling it down to a quenching temperature QT between Ms&#x2212;65&#xb0; C. and Ms&#x2212;115&#xb0; C., being in order to obtain a final structure containing at least 65% of martensite and at least 5% of residual austenite, the sum of the ferrite and bainite contents being less than 10%, Ms being the Ms transformation point of the steel according to the Andrews formula, heating the sheet up to an overaging temperature PT between 360&#xb0; C. and 500&#xb0; C. and maintaining it at said temperature for a time Pt between 10 s and 600 s, and cooling the sheet down to the ambient temperature.

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Destelbergen, Belgium

Gunhild Föjer