Hi Giovanni,
There is an excellent post from Al (803056) regarding welders who are qualified to weld groove welds not being able to pass a simple fillet break test.
http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=163617;hl=Fillet%20Break%20TestThis is an excerpt from that post.
I just finished testing welders (15 welders total) for two different companies using the T-fillet break test on 1/2 inch plate. The test requires a single pass fillet with a 5/16 inch leg and a stop and start half way along the joint. Eleven of the welders had passed the grooved butt joint previously. Not one of the eleven welders (with certs for groove welds) passed on their first attempt, not their second, a few passed on their third attempt. Granted, I'm not easy on the boys, once they fail the initial test they have to pass two consecutive practice break tests before I will administer a second test. The second test consists of two more test plates, both of which have to pass the break test. None of the 15 welders passed the fillet test without some hands-on show and tell. I should have asked for the scrap left over after the testing as payment. I would have been able to take an extra week of vacation!
I have said this for years and I will continue saying, "There is a disconnect between ASME, AWS, and other welding standards when it comes to fillet welds." The ability to pass a grooved butt joint test has little bearing on the welder's ability to pass a "simple" fillet break test. While most codes and standards permit the welder that has passed the grooved butt joint to weld fillets without additional testing, the plain truth is, few of them will pass the fillet break test.
Regards,
Shane