Study of the Inert-Gas Arc Welding of Titanium and its Alloys (3rd Report)

Effect of The Alloying Elements on the Weldability of Titanium Alloys

Abstract

Titanium can alloy with almost all elements, but all of these have not good weldability.
In this investigation, were studied as to what structure and what composition of titanium alloys had good weldability.
Consequently, found that a or α+β titanium alloys containing a small amount of alloying elements, for instance, such as 3% Al-Ti alloy (α) or 2% Al-2% Mn-Ti alloy (α+β) had good weldability. And titanium alloys, seemed to have good weldability, were obtained adding to titanium less than 5% Al or 0.2% C (as α-stabilizer) and less than 4% Mn or 3% Fe (as β-stabilizer). Also, ternary titanium alloys have good weldability, if the total of α-and β-stabilizer is less than 6 % (however, β-stabilizer<α-stabilizer).
Then, the structures in weld metal (as welded) of titanium alloys which thought to have good weldability are as follows :
1) Coarse serrated α in α titanium alloys.
2) Coarse acicular α in α+β titanium alloys.
And the hardness in these weld metals was Hv. 200-300.