Spot Welded Joint Made from Liquid Metal Embrittlement Resistant Zinc Coated Steel Sheet

Patent metadata

Field	Value
Publication number	US-2025034688-A1
Application number	US-202418909715-A
Country	US
Kind code	A1
Filing date	Oct 8, 2024
Priority date	Nov 17, 2017
Publication date	Jan 30, 2025
Grant date	—

Abstract

The present invention relates to a spot welded joint where a steel sheet is made by a method with steps: A. the coating of the steel sheet with a first coating consisting of nickel and having a thickness between 600 nm and 1400nm, the steel sheet having the following composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05<AI<1.0%, 0.75< (Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb≤ 0.5%, B≤ 0.010%, Cr≤ 1.0%, Mo≤ 0.50%, Ni≤ 1.0%, Ti≤ 0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, B. the recrystallization annealing at a temperature between 820 to 1200° C., C. the coating with a second coating based on zinc not comprising nickel.

First claim

What is claimed is:

1 . A spot welded joint comprising:
at least two metal sheets, a first of the metal sheets being coated steel sheet obtained by a method comprising the following successive steps: coating of a steel sheet with a first coating consisting of nickel and having a thickness between 600 nm and 950 nm, the steel sheet having the following composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05≤ Al<1.0%, 0.75< (Si+Al)<3.0%, and on a purely optional basis, one or more elements including: Nb≤ 0.5%, B≤0.010%, Cr≤ 1.0%, Mo≤ 0.50%, Ni≤ 1.0%, Ti≤ 0.5%, a remainder of the composition making up of iron and inevitable impurities resulting from processing; recrystallization annealing of the coated steel sheet at a temperature between 820 to 1200° C.; and coating the steel sheet obtained in recrystallization annealing with a second coating based on zinc not comprising nickel, the joint containing 2 cracks or less having a size above 100 μm and wherein the longest crack has a length below 450 μm.

2 . The spot welded joint as recited in claim 1 wherein a second of the two metal sheets is a steel sheet or an aluminum sheet.

3 . The spot welded joint as recited in claim 1 wherein a second of the metal sheets is a second coated steel sheet including a second diffusion coating including nickel and iron formed through diffusion of nickel into a second steel sheet, the second diffusion coating being directly topped by a second zinc based coating not comprising nickel.

4 . The spot welded joint as recited in claim 2 wherein the at least two metal sheets include a third metal sheet being a steel sheet or an aluminum sheet.

5 . The spot welded joint as recited in claim 1 wherein the composition includes one of the following elements: Nb≤ 0.5%, B≤0.010%, Cr≤ 1.0%, Mo≤ 0.50%, Ni≤ 1.0%, Ti≤ 0.5%,

6 . An automobile vehicle part comprising the spot welded joint as recited in claim 1 .

Assignees

• Arcelormittal

Inventors

• Chakraborty Anirban
• Ghassemi-Armaki Hassan
• Bertho Pascal
• Allely Christian

Classifications

• C23C2/022

  by heating · CPC title

• C23C2/0224

  Two or more thermal pretreatments · CPC title

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title

• C22C38/54

  with boron · CPC title

• C22C38/50

  with titanium or zirconium · CPC title