Some Factors Affecting Porosity of Inert-Gas Arc Welded Ti Metals

Abstract

Commercial pure Titanium can be readily joined by either TIG or MIG inert-gas shield welding process, but occasionally fine blow holes are detected by X-ray examination.
A study was carried out to make clear the effect of welding conditions on the tendency to "blow hole development" in butt joints of 5 mm thick commercial pure Ti plate. As to welding conditions or factors, purity of shielding inert-gas, welding geometry, welding current, welding speed, feeding rate of filler wire and appearance of filler wire were taken into consideration.
It was concluded that ;
1) MIG welding process, being less susceptible to blow hole, is more suitable than TIG welding to obtain more sound welds.
2) Welds made under atmospheres containing nitrogen, oxygen and hydrogen are more susceptible to blow hole than those obtained under pure Argon atmosphere.
3) Cleanliness of the work to be welded and smoothness of filler wire surface are necessary factors to obtain sound welds.
4) To obtain sound welds, suitable ranges of current and speed for welding are necessary.