Press hardened steel with tailored properties
A tailor-welded blank is made of two steels, one steel of Alloy A and one steel of Alloy B. Alloy A comprises 0.10-0.50 wt % C, 0.1-0.5 wt % Si, 2.0-8.0 wt % Mn, 0.0-6.0 wt % Cr, 0.0-2.0 wt % Mo, 0.0-0.15 wt % Ti, and 0.0-0.005 wt % B and wherein Alloy B comprises 0.06-0.12 wt % C, 0.1-0.25 wt % Si, 1.65-2.42 wt % Mn, 0.0-0.70 wt % Cr, 0.08-0.40 wt % Mo, 0.0-0.05 wt % V, and 0.01-0.05 wt % Ti.
1. A tailor-welded blank comprising Alloy A and Alloy B, wherein Alloy A comprises 0.10-0.50 wt % C, 0.1-0.5 wt % Si, 2.0-8.0 wt % Mn, 0.0-6.0 wt % Cr, 0.0-2 wt % Mo, 0.0-0.1 wt % Nb, 0.0-0.15 wt % V, and 0.0-0.005 wt % B, the balance Fe and impurities associated with steelmaking and wherein Alloy B comprises 0.06-0.12 wt % C, 0.1-0.25 wt % Si, 1.65-2.45 wt % Mn, 0.0-0.70 wt % Cr, 0.08-0.40 wt % Mo, 0.025-0.055 wt % Nb, 0.0-0.05 wt % V, 0.01-0.05 wt % Ti, and 0.0-0.002 wt % B, the balance Fe and impurities associated with steelmaking, wherein after press-hardening of the tailor-welded blank Alloy A exhibits an ultimate tensile strength greater than or equal to about 950 MPa and a total elongation of less than or equal to about 18% and Alloy B exhibits an ultimate tensile strength of about 450-800 MPa and a total elongation of greater than or equal to about 12%, and the ultimate tensile strength of Alloy A after press hardening of the tailor-welded blank is higher than the ultimate tensile strength of Alloy B and the total elongation of Alloy A is lower than that of Alloy B.
2. The tailor-welded blank in accordance with claim 1 , wherein the carbon concentration in Alloy A is 0.1-0.35 weight %.
3. The tailor-welded blank in accordance with claim 2 wherein the carbon concentration in Alloy A is 0.22-0.25 weight %.
4. The tailor-welded blank of claim 1 , wherein the manganese concentration in Alloy A is 2.0-5.0 weight %.
5. The tailor-welded blank of claim 1 , wherein the manganese concentration in Alloy A is 3.0 weight %-8.0 weight %.
6. The tailor-welded blank of claim 5 ; wherein the manganese concentration in Alloy A is 3.0 weight %-5.0 weight %.
7. The tailor-welded-blank of claim 1 , wherein the silicon concentration in Alloy A is 0.2-0.3 weight %.
8. The tailor-welded blank of claim 1 , wherein the molybdenum concentration in Alloy A is 0.0-0.6 weight %.
9. The tailor-welded blank of claim 1 , wherein the molybdenum concentration in Alloy A is 0.1-2.0 weight %.
10. The tailor-welded blank of claim 9 , wherein the molybdenum concentration in Alloy A is 0.1-0.6 weight %.
11. The tailor-welded blank of claim 10 , wherein the molybdenum concentration in Alloy A is 0.4-0.5 weight %.
12. The tailor-welded blank of claim 1 , wherein the chromium concentration in Alloy A is 2.0-6.0 weight %.
13. The tailor-welded blank of claim 1 , wherein the chromium concentration in Alloy A is 0.2-6.0 weight %.
14. The tailor-welded blank of claim 13 , wherein the chromium concentration in Alloy A is 0.2-3.0 weight %.
15. The tailor-welded blank of claim 1 , wherein the niobium concentration in Alloy A is 0.01-0.1 weight %.
16. The tailor-welded blank of claim 1 , wherein the vanadium concentration in Alloy A is 0.01-0.15 weight %.
17. The tailor-welded blank of claim 1 , wherein Alloy A is coated with aluminum, zinc, or alloys thereof.
18. The tailor-welded blank of claim 1 , wherein Alloy B is coated with aluminum, zinc, or alloys thereof.
19. A method of manufacturing a tailor-welded blank according to claim 1 comprising the steps of:
a. obtaining a steel of Alloy A,
b. obtaining a steel of Alloy B,
c. welding the steel of Alloy A to the steel of Alloy B;
d. heating the welded blank to a temperature above the Ac1 temperature for Alloy A,
e. forming in a die,
f. cooling said blank in the die.
20. A method of manufacturing a tailor-welded blank according to claim 1 comprising the steps of:
a. obtaining a steel of Alloy A;
b. obtaining a steel of Alloy B;
c. welding the steel of Alloy A to the steel of Alloy B;
d. heating the welded blank to a temperature above the Ac3 temperature for Alloy A,
e. forming in a die,
f. cooling said blank in the die.
21. A tailor-welded blank comprising Alloy A and Alloy B, wherein Alloy A comprises 0.10-0.50 wt % C, 0.1-0.5 wt % Si, 2.0-8.0 wt % Mn, 0.0-6.0 wt % Cr, 0.0-2 wt % Mo, 0.001-0.055 weight % Nb, 0.0-0.15 wt % V, and 0.0-0.005 wt % B, the balance Fe and impurities associated with steelmaking and wherein Alloy B comprises 0.06-0.12 wt % C, 0.1-0.25 wt % Si, 1.65-2.45 wt % Mn, 0.0-0.70 wt % Cr, 0.08-0.40 wt % Mo, 0.025-0.055 wt % Nb, 0.0-0.05 wt % V, 0.01-0.05 wt % Ti, and 0.0-0.002 wt % B, the balance Fe and impurities associated with steelmaking, wherein after press-hardening of the tailor-welded blank Alloy A exhibits an ultimate tensile strength greater than or equal to about 950 MPa and a total elongation of less than or equal to about 18% and Alloy B exhibits an ultimate tensile strength of about 450-800 MPa and a total elongation of greater than or equal to about 12%, and the ultimate tensile strength of Alloy A after press hardening of the tailor-welded blank is higher than the ultimate tensile strength of Alloy B and the total elongation of Alloy A is lower than that of Alloy B.