Ok, let me see if can answer some of this.....
>In general, what is the pass fail rate for the fillet break test?
I'm gonna guess at 85-90% pass rate
>Are you requiring the welders to make the 5/16 inch fillet weld as a single pass fillet?
yes(mostly FCAW)...I can't remember when we did a SMAW last...but that would have been with a large dia E7028
>What is the primary reason for failing the test, i.e., undercut, overlap, incomplete fusion to the root, etc.?
incomplete fusion at the root due to incorrect gun/travel angle, and then undercut/overlap coming in second for the less experienced, again mainly due to gun/travel angle(for some reason they like to use a push angle and it's hard to break them of that)
>Do you know if they have passed a grooved butt joint test prior to taking the fillet break test?
many of the newer welders here lately are promoted from within, so I've had a chance to work with most of them, but the others have been previously tested with other companies.
>If you are testing new hires with previous qualification from another employer, what is the pass fail rate for that group?
I'm gonna say that the previously tested fail more often than the ones that I've had a chance to bring up and worked with(ratio?..hmm maybe a 1/10 fail)...that might not be fair to put them up against the one's I've had a chance to train.
>Once they pass the fillet break test, what is the pass / fail rate for the grooved butt joint?
Pretty good pass rate...capping it off seems to give them the most trouble on the groove test...few bust out at the root, but more often than not the cap causes the most trouble. E70T-1 is pretty fluid.