It seems there is an industry wide shortage of Argon and our gas vendor has put us on allocation (70%) of our prior usage. So I'm looking into the WPS/PQR/WPQ changes I'll need to make to go to CO2. I would like to know if I've got this right here:
For prequalified WPS's - I should only have to do revisions to include CO2 gas as an option.
For WPS's w/ PQR's - I will have to conduct a new test and generate a PQR with CO2 only. (Table 4.5)
For WPQ's - Nothing because shielding gas is not an essential variable. (Table 4.1)
Is this correct, and are there any other caveats? We run FCAW .0625 almost exclusively.
Thanks in advance for your replies.
C.
I believe you have it right. All I'll add is that you should check your manufacturer's data to be sure 100% CO2 is recommended for your wire. Most likely, it is but it's best to check because D1.1 pre-qual WPS's require that you be within recommendations.
Chet
It sounds as though you are currently using GMAW spray mode transfer. Transfer mode can be affected by the shielding gas. You may have to use a mixed gas containing a high percentage of Argon (80% or more) to obtain a "clean" spray transfer mode. Remember, short circuiting mode transfer isn't prequalifed.
Good luck - Al
Al,
Check out the second to last line of first posting.
They are using FCAW almost exclusively,
Regards,
Shane
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