Alloying composition for self-shielded FCAW wires with low diffusible hydrogen and high Charpy V-notch impact toughness
A self-shielded flux cored arc welding electrode is disclosed including a ferrous metal sheath and a core within the sheath enclosing core ingredients comprise a composition window of aluminum, manganese and rare earth metals in wires of about 2.0-3.0 wt. % [Al], 1.0-2.0 wt. % [Mn] and 0.001-0.11 wt. % rare earth metals or 0.001-0.5% rare earth metal oxides, such as, but not limited to, La, Ce, etc. Resulting welds include 0.7-1.0 wt. % [Al] and 1.1-1.5 wt. % [Mn]. Resulting welds have a maximum diffusible hydrogen content of 5 mL/100 g or less, Resulting welds also have a Charpy V-notch toughness at −40° F. of at least 100 ft-lbs.
1. A flux cored welding electrode comprising a ferrous metal sheath and a core within the sheath including core ingredients, the core ingredients comprising, in weight percent based on the total weight of the flux cored welding electrode:
2.0-3.0 aluminum;
1.0-2.0 manganese; and
0.001-0.35 rare earth metal oxide comprising Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Praseodymium (Pr);
wherein the flux cored welding electrode is capable of yielding a weld having a diffusible hydrogen level of 5 ml/100 g or less and a Charpy V-notch toughness at −40° F. of at least 100 ft-lbs.
2. The flux cored welding electrode of claim 1 , wherein the rare earth metal of the rare earth metal oxide comprises up to 0.11 wt. % of the total weight of the metal sheath and core ingredients.
3. The flux cored welding electrode of claim 1 , wherein the rare earth metal oxide comprises Ce 2 O 3 —La 2 O 3 —Nd 2 O 3 —Pr 2 O 3 .
4. The flux cored welding electrode of claim 1 , wherein the core ingredients further comprise, in weight percent, based on the total weight of the flux cored welding electrode:
9.54 of a first sintered fluoride;
4.53 sintered oxide;
0.42 of a second sintered fluoride;
2.04 aluminum;
1.77 magnesium;
1.00 manganese;
0.87 nickel;
0.21 Ce 2 O 3 —La 2 O 3 —Nd 2 O 3 —Pr 2 O 3 ; and
0.36 iron.
5. The flux cored welding electrode of claim 4 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
6. The flux cored welding electrode of claim 1 , wherein the core ingredients further comprise, in weight percent, based on the total weight of the flux cored welding electrode:
9.34 of a first sintered fluoride;
4.53 sintered oxide;
0.83 of a second sintered fluoride;
2.10 aluminum;
1.77 magnesium;
1.01 manganese;
0.98 nickel;
0.10 Ce 2 O 3 —La 2 O 3 —Nd 2 O 3 —Pr 2 O 3 ; and
0.03 iron.
7. The flux cored welding electrode of claim 6 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
8. The flux cored welding electrode of claim 1 , wherein the core ingredients further comprise, in weight percent, based on the total weigh of the flux cored welding electrode:
9.13 of a first sintered fluoride;
4.51 sintered oxide;
0.42 of a second sintered fluoride;
2.04 aluminum;
1.77 magnesium;
0.96 manganese;
0.87 nickel;
0.44 zirconium dioxide;
0.07 Ce 2 O 3 —La 2 O 3 —Nd 2 O 3 —Pr 2 O 3 ; and
0.53 iron.
9. The flux cored welding electrode of claim 8 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
10. A flux composition for a cored welding electrode, the flux composition comprising, in weight percent based on the total weight of the flux cored welding electrode:
2.0-3.0 aluminum;
1.0-2.0 manganese; and
0.001-0.11 rare earth metal, wherein the rare earth metal comprises a rare earth metal oxide, and wherein the rare earth metal oxide comprises Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Praseodymium (Pr).
11. The flux composition of claim 10 , wherein the rare earth metal oxide comprises Ce 2 O 3 —La 2 O 3 —Nd 2 O 3 —Pr 2 O 3 .
12. The flux composition of claim 10 , wherein the composition comprises, in weight percent, based on the total weight of the flux cored welding electrode:
9.54 of a first sintered fluoride;
4.53 sintered oxide;
0.42 of a second sintered fluoride;
2.04 aluminum;
1.77 magnesium;
1.00 manganese;
0.87 nickel
0.07 rare earth metals; and
0.36 iron.
13. The flux composition of claim 12 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
14. The flux composition of claim 10 , wherein the composition comprises, in weight percent, based on the total weight of the flux cored welding electrode:
9.13 of a first sintered fluoride;
4.53 sintered oxide;
0.83 of a second sintered fluoride;
2.10 aluminum;
1.77 magnesium;
1.01 manganese;
0.98 nickel
0.04 rare earth metals; and
0.83 iron.
15. The flux composition of claim 14 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
16. The flux composition of claim 10 , wherein the composition comprises, in weight percent, based on the total weight of the flux cored welding electrode:
9.13 of a first sintered fluoride;
4.51 sintered oxide;
0.42 of a second sintered fluoride;
2.04 aluminum;
1.77 magnesium;
0.96 manganese;
0.87 nickel
0.44 zirconium dioxide
0.03 rare earth metals; and
0.53 iron.
17. The flux composition of claim 16 , wherein the first sintered fluoride comprises BaLiF 3 , the sintered oxide comprises Li 2 O—CaO—SiO 2 —Fe 3 O 4 and the second sintered fluoride comprises KLiF 2 .
18. A flux cored welding electrode comprising a ferrous metal sheath and a core within the sheath including core ingredients, the core ingredients comprising, in weight percent based on the total weight of the flux cored welding electrode:
2.0-3.0 aluminum;
1.0-2.0 manganese; and
0.001-0.5 rare earth metal oxide comprising Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Praseodymium (Pr);
wherein the flux cored welding electrode is capable of yielding a weld having a diffusible hydrogen level of 5 ml/100 g or less and a Charpy V-notch toughness at −40° F. of at least 100 ft-lbs.