High strength weldable Al—Mg alloy
An aluminum alloy product having high strength, excellent corrosion resistance and weldability, having the following composition in wt. %: Mg 3.5 to 6.0, Mn 0.4 to 1.2, Fe<0.5, Si<0.5, Cu<0.15, Zr<0.5, Cr<0.3, Ti 0.03 to 0.2, Sc<0.5, Zn<1.7, Li<0.5, Ag<0.4, optionally one or more of the following dispersoid forming elements selected from the group consisting of erbium, yttrium, hafnium, vanadium, each <0.5 wt. %, and impurities or incidental elements each <0.05, total <0.15, and the balance being aluminum.
1. A method of manufacturing an aluminium rolled product, the method comprising the steps of:
casting an aluminium alloy consisting of the following composition in wt. %:
Mg 3.5 to 6.0
Mn 0.4 to 1.2
Fe≦0.14
Si≦0.12
Cu≦0.05
Zr 0.05 to 0.25
Cr 0.05 to 0.1
Ti 0.05-0.11
Sc 0.1 to 0.3
Zn 0.2 to 0.65
Ag<0.4,
and impurities or incidental elements each <0.05, total <0.15,
and the balance being aluminum,
wherein both Cr and Ti are present in equal or about equal quantities,
pre-heating at a temperature in a range of 280° C. to 500° C. prior to hot rolling,
hot rolling the cast alloy;
cold rolling the hot rolled alloy to form a cold rolled product;
stretching the cold rolled product 1.5%;
annealing the cold rolled and stretched product at a temperature in the range of 100° C. to 500° C.
2. A method according to claim 1 , wherein the Ti content is in the range 0.05 to 0.1 wt. %.
3. A method according to claim 1 , wherein Mn is in the range of 0.6 to 1.0 wt. %.
4. A method according to claim 1 , wherein Mn is in the range of 0.65 to 0.9 wt. %.
5. A method according to claim 1 , wherein the combined amount of Cr and Zr is in the range 0.1 to 0.25 wt. %.
6. A method according to claim 1 , wherein the combined amount of Cr and Ti is in the range 0.1 to 0.21 wt. %.
7. A method according to claim 1 , wherein the combination of Zr and Ti is in the range 0.1 to 0.25 wt. %.
8. A method to claim 1 , wherein the combined amount of Cr and Ti and Zr is in the range 0.15 to 0.36 wt. %.
9. A method according to claim 1 , wherein Zr is in the range of 0.08 to 0.16 wt. %.
10. A method according to claim 1 , wherein Zn is in the range of 0.35 to 0.6 wt. %.
11. A method according to claim 1 , wherein Zn is in the range 0.2 to 0.35 wt. %.
12. A method according to claim 1 , wherein Mg is in the range 3.6 to 4.4 wt. %.
13. A method according to claim 1 wherein Mg is in the range 3.8 to 4.3 wt. %.
14. A method according to claim 13 , wherein Mn is in the range of 0.6 to 1.0 wt. %, wherein in the aluminium alloy the quantity of Cr in the aluminium alloy is within 0.02 wt. % of the quantity of Ti.
15. A method according to claim 1 , wherein in the aluminium alloy the quantity of Cr in the aluminium alloy is within 0.02 wt. % of the quantity of Ti.
16. A method according to claim 15 , wherein Mn is in the range of 0.9 to 1.2 wt. %.
17. A method according to claim 15 , wherein the aluminium alloy consists of the following composition in wt. %:
Mg 5.2 to 6.0
Mn 0.9 to 1.2
Fe≦0.14
Si≦0.12
Cu≦0.05
Zr 0.08 to 0.16
Cr 0.05 to 0.1
Ti 0.05 to 0.11
Sc 0.15 to 0.3
Zn 0.6 to 0.65
Ag<0.4,
and impurities or incidental elements each <0.05, total <0.15, and the balance being aluminum.
18. A method according to claim 1 , wherein Mn is in the range of 0.9 to 1.2 wt. %.
19. A method according to claim 18 , wherein Sc is in the range of 0.15-0.3 wt. %.
20. A method according to claim 19 , wherein Zn is in the range 0.2 to 0.35 wt. %.
21. A method according to claim 1 , wherein the product is in the form of a rolled product, sheet, plate, or a product obtained by plastic deformation.
22. A method according to claim 1 , wherein the product is in the form of a sheet, plate, or product obtained by plastic deformation as part of an aircraft, a vessel or a rail or road vehicle.
23. A method according to claim 1 , wherein the product has a thickness in the range of 15 to 150 mm at its thickest cross section point.
24. A method according to claim 1 , wherein the product is an extruded product has a thickness in the range of 0.6 to 80 mm at its thickest cross section point.
25. A method according to claim 1 , wherein the product is in the form of a plate product having a thickness in the range of 0.6 to 12.5 mm at its thickest cross section point.
26. A method according to claim 1 , wherein the product is an aircraft stringer.
27. A method according to claim 1 , wherein the aluminium alloy has a Mg content of 5.2 to 6.0 wt. %.
28. A method according to claim 1 , wherein the product is aircraft fuselage sheet.
29. A method according to claim 1 , wherein the pre-heating is at a temperature in a range of 400° C. to 480° C. prior to hot rolling.