AWS D1.1-2004 FCAW & GMAW Power Supplies

[Rich2001]

If you haven't seen it yet the new AWS D1.1-2004 Structural Steel welding code has added power supplies requirements for FCAW and GMAW welding.

[blue]Section 3.2.4:

“3.2.4 FCAW and GMAW Power Sources. FCAW and GMAW that is done with prequalified WPSs shall be performed using constant voltage (CV) power supplies.” [/blue]

This is in the prequalification section so it does not prohibit the use of CC power supplies, it just requires users of CC power supplies to qualify their procedures by testing in accordance with Section 4 of the code.

 

[CWIC]

Hi Rich2001.
I have the new code (available last year). I'm glad they finally incorporated this provision into the code. While it does not prohibit the use of CC power sources for semiautomatic processes, I've yet to se a modified CC machine comply with the tolerances listed in Table 4.5, specifically the 7% tolerance on voltage.

The modified machines typically use a box that conditions the output of CC machine permitting an LN-25 (or equivelant) to be used. There is a switch in many of these feeders so that they can be swapped from a CC to a CV machine or vice-versa.

I wrote a SMRF QC procedure back in 1996 which requires the use of CC power supplies for GMAW/FCAW. One of SEAOSC's technical committee's has adopted this procedure and several of my clients now require the same once demonstrated via a calibrated meter.
BTW, DOT/Caltrans has not permitted modified power sources on some of their projects for the last few years.

 

[JTMcC]

I know this is old, but, do you have a specific reference to the caltrans requirments for machines?

Thanks, JTMcC.