Welding flux composition and corresponding method for welding metals

17:

• The method as recited in claim 16 wherein the titanate is chosen from the group consisting of:
• Na2Ti3O7, NaTiO3, K2TiO3, K2Ti2O5, MgTiO3, SrTiO3, BaTiO3, CaTiO3, FeTiO3 and ZnTiO4 or mixtures thereof.

18:

• The method as recited in claim 16 wherein a thickness of the welding flux is between 10 to 140 μm.

19:

• The method as recited in claim 16 wherein a percentage of the nanoparticulate oxide in the welding flux is below or equal to 80 wt. %.

20:

• The method as recited in claim 16 wherein a percentage of the nanoparticulate oxide in the welding flux is above or equal to 10 wt. %.

21:

• The method as recited in claim 16 wherein the nanoparticles have a size between 5 and 60 nm.

22:

• The method as recited in claim 16 wherein a percentage of titanate in the welding flux is above or equal to 45 wt. %.

23:

• The method as recited in claim 16 wherein a diameter of the titanate is between 1 and 40 μm.

24:

• The method as recited in claim 16 wherein the welding flux is applied with a flux hopper.

25:

• The method as recited in claim 16 further comprising applying a shielding flux on the at least two metallic substrates, ahead of the welding head, simultaneously with the welding, so that the shielding flux covers the welding flux.

26:

• The method as recited in claim 25 wherein the shielding flux is applied with a flux hopper.

27:

• The method as recited in claim 16 wherein the welding flux is also a shielding flux.

28:

• The method as recited in claim 16 wherein the welding flux further includes lime, silica, manganese oxide and calcium fluoride in the form of particles of micrometric or millimetric size.

29:

• The method as recited in claim 16 wherein the welding is done by Submerged Arc Welding, Narrow Gap Welding based on Submerged Arc Welding or Laser Arc Hybrid Welding based on Submerged Arc Welding.

30:

• Welding equipment comprising:
• a welding head, a first flux hopper positioned ahead of the welding head and suitable for the application of a shielding flux and a second flux hopper suitable for the application of a welding flux and positioned further ahead of the welding head than the first flux hopper.