short arc vs. pulse arc GMAW

By LTRN Date 11-14-2002 18:34

What are the pros and cons of the above mentioned processes?
I have been told that GMAW short circuiting does not penetrate very well and is not allowed for process piping at some petro/chem facilities. I would like to verify this. Thank you for the assistance.

By bspeirs (*)

Date 11-16-2002 02:07

Some companies do not allow MIG for weld-o-lets. Hard to get full penetration.

Some companies (or at least the local inspector) do not "allow" MIG, but if you look in their standards, it is not uncommon to find MIG allowed for root passes, or for complete welds up to 3/8" thick.

It is interesting that the same companies who do not like MIG in plant piping do not seem to have an issue with fully automatic, narrow groove MIG welds on pipelines.

Most should not have any issue with FCAW.

By LTRN Date 11-19-2002 15:07

Bspeirs,
Thanks for the info.

By underwooddl Date 11-19-2002 18:51

Some process specifications do not permit the use of GMAW in the short-circuiting transfer mode.
Some will permit it only for joining relatively thin sections.
ASME Section IX mentions the following arc transfer modes for GMAW, short-circuiting, globular, spray, and pulsating.

Try the following link to the National Board Web site for an interesting article by Mike Houle about GMAW-S (short-circuiting) transfer:

http://www.nationalboard.org/Classics/classic5.html