Welding with titanium requires extreme cleanliness. Grind or file off mill scale. Clean surface oxides with a 35% nitric - 5 % hydrofluoric acid solution at room temperature, then rinse with water and air dry. Grease or oils should be cleaned with a non-chlorinated degreasing solvent, acetone or methanol. Light Oil can be washed away with a normal household detergent, then air dried.
Titanium is a reactive metal and as such it is sensitive to embrittlement by oxygen, nitrogen, and hydrogen, within the weld zone area, at temperatures above 500°F. Consequently the weld metal must be protected against atmospheric contamination that may be caused by these elements. This can be most easily attained by holding the shielding gas over the weld area until it cools to approximately 600°F.
Argon is the recommended shielding gas, however an argon-helium mixture will give greater penetration although at the expense of arc stability. The filler metal composition is usually matched to the grade of titanium being welded.
Titanium Welding
in MapleWeld
