Welding process of titanium and titanium alloy
The welding methods used are argon arc welding, submerged arc welding and electron beam welding.
1, clean up before welding
The contamination of the base metal or wire surface must be thoroughly removed and dried before welding. It can be washed with a suitable solvent or degreased by steam or vaporization.
When cutting, blasting, nozzle or wire brush to remove oxide scale in the weld zone, it is necessary to carry out chemical cleaning such as pickling, gloss treatment and washing.
(3) Except oxide film
It is removed by short-time pickling. The pickling agents used are: HF with a volume fraction of 2% to 4%, HNO3 with a volume fraction of 30% to 40%, and rinsed with water containing no chloride ions after pickling. And dry to prevent hydrogenation of the base material.
2, welding process
Argon arc welding is the most widely used welding method for welding titanium and titanium alloys. TIGs below 3mm are tungsten argon arc welding, and plates above 3mm are selected by argon arc welding.
3. Welding materials and requirements
The purity of argon is critical: purity (Ar) is not less than 99.99% and must be very dry.
Commonly used welding wire has seven kinds of TA1, TA2, TA3, TA4, TA5, TA6 and TC3.
4, the main points of the process
(1) Two-way gas protection;
(2) The welding parts are strictly cleaned;
(3) The groove and assembly dimensions should be strictly controlled;
(4) Small current and large welding speed welding to prevent overheating
(5) to ensure the protection effect of argon;
(6) Argon argon and lag argon in advance (the arc extinguishing should be stopped below 400 °C).