we was doing automatic TIG welds of round 304 parts, butt joint. to achieve about .100" penetration, the 1.12" diameter part rotates at 1.7 rpm. we used 97% argon and 3% hyfrogen. the resulting joint has many long voids (.010 wide, by .100 long). we know hydrogen may cause the problem but it would not be in such size.
i can not attach photo here to show the voids.
anyone knows the cause and can help us?
thanks.