Importance

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Abstract

One subject of the invention is a process for manufacturing a metal strip having a metal coating for corrosion protection, comprising the steps consisting in:

making the metal strip pass through a bath of molten metal, comprising 0.2 to 8% by weight of aluminum and magnesium in the following proportions: 0.1 to 8% by weight of magnesium for an aluminum content equal to or greater than 0.2% but less than 4% by weight ora content greater than 5% but less than or equal to 8% by weight of magnesium for an aluminum content equal to or greater than 4% but less than or equal to 8% by weight, and comprising up to 0.3% by weight of addition elements, the balance being zinc and inevitable impurities; thenwiping the coated metal strip by means of nozzles that spray a gas on each side of the strip, said gas having an oxidizing power lower than that of an atmosphere consisting of 4% oxygen by volume and 96% nitrogen by volume; and thenmaking the strip pass through a confinement zone bounded: at the bottom, by the wiping line and the upper external faces of said wiping nozzles,at the top, by the upper part of two confinement boxes placed on each side of the strip, just above said nozzles, and having a height of at least 10 cm in relation to the wiping line andon the sides, by the lateral parts of said confinement boxes,the atmosphere in said confinement zone having an oxidizing power lower than that of an atmosphere consisting of 4% oxygen by volume and 96% nitrogen by volume and higher than that of an atmosphere consisting of 0.15% oxygen by volume and 99.85% nitrogen by volume.

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First Claim