Welded steel sheets, and sheets thus produced

Patent metadata

Field	Value
Publication number	US-11959150-B2
Application number	US-202117470257-A
Country	US
Kind code	B2
Filing date	Sep 9, 2021
Priority date	Mar 25, 2016
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

A steel sheet that is welded and then cold rolled to a thickness between 0.5 mm and 3 mm, the deformation ratio created by cold rolling in the base metal is equal to εMB, for which the deformation ratio created by the cold rolling in the welded joint is equal to εS, where:0.4≤ɛSɛ⁢M⁢B<0.7.

First claim

What is claimed is:

1. A steel sheet welded and then cold rolled to a thickness between 0.5 mm and 3 mm, the steel sheet comprising:
a base metal and a welded joint;
a deformation ratio created by cold rolling in the base metal being equal to ε MB ;
a deformation ratio created by cold rolling in the welded joint being equal to ε S ;

0.4
≤

ε
⁢
S

ε
⁢
MB

≤
0.7

;

and
a direction of the welded joint extending perpendicular to a direction of cold rolling.

2. The steel sheet as recited in claim 1 wherein the steel sheet has a tensile strength Rm greater than 600 MPa.

3. The steel sheet as recited in claim 1 wherein a composition of the base metal includes, as contents expressed as weight percent:
0.05%≤C≤0.17%;
1.1%≤Mn≤2.76%;
0.07%≤Si≤0.7%;
S≤0.008%;
P≤0.030%;
0.015%≤Al≤0.61%;
Mo≤0.13%;
Cr≤0.55%;
Cu<0.2%;
Ni≤0.2%;
Nb≤0.050%;
Ti≤0.045%;
V≤0.010%;
B≤0.005%;
Ca<0.030%; and
N≤0.007%,
a remainder being iron and unavoidable impurities due to processing.

4. The steel sheet as recited in claim 1 wherein the steel sheet has a tensile strength Rm greater than 690 MPa.

5. The steel sheet as recited in claim 4 wherein a composition of the base metal includes, the contents being expressed as weight percent:
0.13%≤C≤0.3%;
1.8%≤Mn≤3.5%;
0.1%≤Si≤2%;
0.1%≤Al≤2%;
1%≤Si+Al≤2.5%; and
N≤0.010%;
a remainder being iron and unavoidable impurities due to processing.

6. The steel sheet as recited in claim 5 wherein the composition of the base metal includes, the contents being expressed as weight percent:
Ni+Cr+Mo<1%;
Ti≤0.1%;
Nb≤0.1%; and
V≤0.1%.

7. The steel sheet as recited in claim 1 wherein the steel sheet is suitable for press-hardening for the manufacture of parts having tensile strength Rm greater than 1000 MPa.

8. The steel sheet as recited in claim 7 wherein the composition of the base metal includes, the contents being expressed as weight percent:
0.15%≤C≤0.5%;
0.4%≤Mn≤3%;
0.1≤Si≤1%;
Cr≤1%;
Ti≤0.2%;
Al≤0.1%; and
B≤0.010%;
a remainder being iron and unavoidable impurities due to processing.

9. The steel sheet as recited in claim 8 wherein the composition of the base metal includes at least one of, the contents being expressed as weight percent:
0.25%≤Nb≤2%; and
Nb≤0.060%.

10. The steel sheet as recited in claim 1 wherein the base metal is a martensitic steel with a tensile strength Rm between 1200 MPa and 1700 MPa.

11. The steel sheet as recited in claim 10 wherein the composition of the base metal includes, the contents being expressed as weight percent:
0.10%≤C≤0.30%;
0.40%≤Mn≤2.20%;
0.18%≤Si≤0.30%;
0.010%≤Al≤0.050%; and
0.0025≤B≤0.005%;
a remainder being iron and impurities due to processing.

12. The steel sheet as recited in claim 11 wherein the composition of the base metal includes at least one of, the contents being expressed as weight percent:
0.020%≤Ti≤0.035%;
Cu≤0.10%;
Ni≤0.10%; and
Cr<0.21%.

13. The steel sheet as recited in claim 1 wherein in the welded joint is a flash weld.

14. The steel sheet as recited in claim 1 wherein the welded joint is a laser weld.

15. The steel sheet as recited in claim 1 wherein the base metal is a dual phase steel.

16. The steel sheet as recited in claim 1 wherein the base metal is a TRIP steel.

Assignees

• Arcelormittal

Inventors

• Dechassey Emmanuel
• Silvy-Leligois Christophe
• Chicharro Herranz Francisco
• Polo Mestre Vicente
• Theyssier Marie-Christine
• Celotto Thierry
• Kaczynski Christine
• Dupuy Thomas
• Ngo Quang-Tien

Classifications

• C21D9/46 Primary

  for sheet metals · CPC title

• B21B15/0085

  Joining ends of material to continuous strip, bar or sheet · CPC title

• B23K11/0073

  Butt welding of long articles advanced axially · CPC title

• B23K11/04

  Flash butt welding · CPC title

• B23K26/206

  Laser sealing · CPC title