Assembly of an aluminum component and of a press hardened steel part having an alloyed coating comprising silicon, iron, zinc and magnesium, the balance being aluminum

Patent metadata

Field	Value
Publication number	US-11753085-B2
Application number	US-202017602230-A
Country	US
Kind code	B2
Filing date	Apr 3, 2020
Priority date	Apr 9, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

An assembly of an aluminum-based part and a press hardened steel part provided with an alloyed coating including in weight percent, 0.1 to 15.0% silicon, 15.0 to 70% of iron, 0.1 to 20.0% of zinc, 0.1 to 4.0% of magnesium, the balance being aluminum, on at least one of the surfaces thereof placed so as to be in contact with the aluminum-based part.

First claim

What is claimed is:

1. An assembly comprising:
an aluminum-based element; and
a press-hardened steel part having an alloyed coating provided on at least one of the surfaces of the hardened steel part, the alloyed coating comprising in weight percent, 0.1 to 15.0% silicon, 15.0 to 70% of iron, 0.1 to 20.0% of zinc, 0.1 to 4.0% of magnesium, a balance being aluminum, inevitable impurities and optionally one or more additional elements selected from the group consisting of Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Sr, Cr, Ni and Bi, the hardened steel part being joined to the aluminum-based element.

2. The assembly as recited in claim 1 wherein the alloyed coating comprises an intermetallic layer Fe 3 Al and an interdiffusion layer Fe—Si—Al.

3. The assembly as recited in claim 1 wherein a microstructure of the alloyed coating comprises at least one of an Zn 2 Mg phase and a Mg 2 Si phase.

4. The assembly as recited in claim 1 wherein the press hardened steel part is joined to the aluminum-based element by adhesive bonding, welding, sealing, crimping, clinching or riveting.

5. The assembly as recited in claim 1 , wherein the alloyed coating comprises the one or more additional elements, and a content of each additional element is less than 0.3%.

6. A method for the manufacture of the assembly as recited in claim 1 comprising:
A. providing a steel sheet pre-coated on at least one of the surfaces with a pre-coating comprising in weight percent, 0.1 to 20.0% silicon, 0 to 10% of iron, 0.1 to 25.0% of zinc, and 0.1 to 6.0% of magnesium, a balance being aluminum, inevitable impurities and optionally one or more additional elements selected from the group consisting of Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Cr, Ni and Bi;
B. cutting the pre-coated steel sheet to obtain a blank;
C. austenitization treating the blank to obtain a fully austenitic microstructure in the steel;
D. transferring the blank into a press tool;
E. hot-forming of the blank;
F cooling the blank to obtain the press hardened steel part with the alloyed coating; and
G. assembling the press hardened steel part with the aluminum-based element.

7. The method as recited in claim 6 wherein in step C), the austenitization treatment is performed between 800 and 1100° C.

8. The method as recited in claim 6 wherein in step E), the hot-forming is performed by hot-stamping or roll-forming.

9. The method as recited in claim 6 wherein in step G), the press hardened steel part is joined to the aluminum-based element by adhesive bonding, welding, sealing, crimping, clinching or riveting.

10. A part for a vehicle comprising the assembly as recited in claim 1 .

11. The part as recited in claim 10 wherein the part is a front beam, a rear bumper beam, a door reinforcement, a windscreen upright reinforcement, a B-pillar reinforcement, a floor and a roof reinforcement, a Roof or a dash panel cross member.

12. A vehicle comprising the part as recited in claim 10 .

13. A method comprising using the assembly as recited in claim 1 for manufacture of a part for a vehicle or for manufacture of a vehicle.

Assignees

• Arcelormittal

Inventors

• Machado Amorim Tiago
• Morel Stephane
• Dosdat Laurence
• Gregoire Astrid

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• C22C21/00 Primary

  Alloys based on aluminium · CPC title

• C22C21/10 Primary

  with zinc as the next major constituent · CPC title

• B62D29/007 Primary

  predominantly of special steel or specially treated steel, e.g. stainless steel or locally surface hardened steel · CPC title

• C23C30/00

  Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence) · CPC title