By -
Date 10-13-2005 00:12
Yes, I have done applications using the H2 mixes, many times. To be perfectly honest, I noticed very little differences. Using this mix in the overlay process had little difference, if any, than the 98/2. I don't know what you mean by hit or miss problems. The Ar-He mixes are recommended for the pure austenitics such as nickel alloys, but I have never had a problem with the 98/2 mix and a 320 or 320LR when overlaying a butter pass of 309L. Never..In our experience, especially in Europe, the H2 mix is more popular in certain applications, mostly groove welds where side wall tie-in is concerned. Then again, I've never had any problems with tie-in problems with the 98/2, either.
By -
Date 10-13-2005 00:16
One more thing..sorry..The attributes of H2 are VERY similar to helium. Very similar. I didn't say EXACT, but very similar. As stated before, the use of both H2 and He has both positive and negative results, depending on the application and the % of both. Also be prepared to pay quite a bit more here in the USA.