Coated metal band having an improved appearance

Patent metadata

Field	Value
Publication number	US-11371128-B2
Application number	US-201916409273-A
Country	US
Kind code	B2
Filing date	May 10, 2019
Priority date	May 14, 2009
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

A hot-dip-coated, non-skin-passed, cold-rolled metal strip is provided. The metal coating of the metal strip includes a waviness Wa0.8 of less than or equal to 0.70 μm, 0.2 to 8% by weight of aluminum and magnesium, and up to 0.3% by weight of additional elements, the balance being zinc and inevitable impurities. Metal parts are also provided.

First claim

What is claimed is:

1. A hot-dip-coated, non-skin-passed, cold-rolled metal strip obtained by a process comprising the following steps:
passing a metal strip through a bath of molten metal to obtain a coated metal strip, the bath comprising:
0.2 to 4% by weight of aluminum,
0.1 to 8% by weight of magnesium,
up to 0.3% by weight of additional elements, and
a balance being zinc and inevitable impurities; then

wiping the coated metal strip by means of nozzles that spray a gas on each side of the coated metal 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 then
making the coated metal strip pass through a confinement zone bounded:
at the bottom, by a wiping line and upper external faces of said wiping nozzles,
at the top, by an upper part of two confinement boxes placed on each side of the coated metal strip, just above said nozzles, and having a height of at least 10 cm in relation to the wiping line and
on the sides, by lateral parts of said confinement boxes,

an 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,
a metal coating of the coated metal strip so obtained including:
a waviness Wa 0.8 of less than or equal to 0.70 μm;
a composition of the metal coating comprising:
0.2 to 4% by weight of aluminum,
0.1 to 8% by weight of magnesium; and
up to 0.3% by weight of the additional elements, the balance being zinc and inevitable impurities.

2. The hot-dip-coated, non-skin-passed, cold-rolled metal strip as recited in claim 1 , wherein the metal strip is a steel strip.

3. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 1 , which is deformed into a metal part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.65 μm or less.

4. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 1 , which is deformed into a metal part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.60 μm or less.

5. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 1 , which is deformed into a metal part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.55 μm or less.

6. A hot-dip-coated, non-skin-passed, cold-rolled metal strip obtained by a process comprising the following steps:
passing a metal strip through a bath of molten metal to obtain a coated metal strip, the bath comprising:
4% to 8% by weight of aluminum,
greater than 5% to 8% by weight of magnesium,
up to 0.3% by weight of additional elements, and
a balance being zinc and inevitable impurities; then

wiping the coated metal strip by means of nozzles that spray a gas on each side of the coated metal 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 then
making the coated metal strip pass through a confinement zone bounded:
at the bottom, by a wiping line and upper external faces of said wiping nozzles,
at the top, by an upper part of two confinement boxes placed on each side of the coated metal strip, just above said nozzles, and having a height of at least 10 cm in relation to the wiping line and
on the sides, by lateral parts of said confinement boxes,

an 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,
a metal coating of the coated metal strip so obtained including:
a waviness Wa 0.8 of less than or equal to 0.70 μm;
a composition of the metal coating comprising:
4 to 8% by weight of aluminum,
greater than 5% but less than or equal to 8% by weight of magnesium; and
up to 0.3% by weight of the additional elements, the balance being zinc and inevitable impurities.

7. The hot-dip-coated, non-skin-passed, cold-rolled metal strip as recited in claim 6 , wherein the metal strip is a steel strip.

8. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 6 , which is deformed into a metal part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.65 μm or less.

9. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 6 , which is deformed into a metal, part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.60 μm or less.

10. The hot-dip coated, non-skin-passed, cold-rolled metal strip as recited in claim 6 , which is deformed into a metal part, wherein the metal coating of the part has a waviness Wa 0.8 of 0.55 μm or less.

11. A metal part comprising:
a hot-dip-coated, cold-rolled metal strip obtained by a process comprising the following steps:
passing a metal strip through a bath of molten metal to obtain a coated metal strip, the bath comprising:
0.2 to 8% by weight of aluminum,
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 or
greater than 5% 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,

up to 0.3% by weight of additional elements, and
a balance being zinc and inevitable impurities; then

wiping 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 then
making the strip pass through a confinement zone bounded:
at the bottom, by a wiping line and upper external faces of said wiping nozzles,
at the top, by upper part of two confinement boxes placed on each side of the coated metal strip, just above said nozzles, and having a height of at least 10 cm in relation to the wiping line and
on the sides, by lateral parts of said confinement boxes,

an 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,
a metal coating of the coated metal strip so obtained including:
a waviness Wa 0.8 of less than or equal to 0.70 μm prior to any skin pass operation;
a composition of the metal coating comprising:
0.2 to 8% by weight of aluminum,
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 or
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

up to 0.3% by weight of the additional elements, the balance being zinc and inevitable impurities;

the coated metal strip undergoing a skin pass operation and then being deformed into a metal part, wherein the metal coating of the metal part also has a waviness Wa 0.8 of less than or equal to 0.65 μm after the skin pass operation and deformation.

12. The metal part as recited in claim 11 wherein the metal coating has a waviness Wa 0.8 of 0.60 μm or less after the skin pass operation and deformation.

13. The metal part as recited in claim 11 wherein the metal coating has a waviness Wa 0.8 of 0.55 μm or less after the skin pass operation

Assignees

• Arcelormittal

Inventors

• Diez Luc
• Mataigne Jean-Michel
• Orsal Bertrand
• Saint Raymond Hubert

Classifications

• Y10T428/12993

  Surface feature [e.g., rough, mirror] · CPC title

• C23C2/20 Primary

  Strips; Plates · CPC title

• C22C18/04

  with aluminium as the next major constituent · CPC title

• B32B15/012

  one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy · CPC title

• C22C18/00

  Alloys based on zinc · CPC title