I am a relative noob hobbyist welder. I have done some testing on fillet welds I have done recently. I may have even have posted on this forum some evidence of the fillet weld break tests I have completed on 1/4" to 1/2" mild steel over the last couple of months.
http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=255011. Anyway in those tests I found that I could get the 1/4" steel plate to bend before the weld broke.
In contrast I recently welded a 3/8" plate to a 1/2" plate. Afterwards I went at the 3/8" plate with the hammer and have not been able to bend the 3/8" plate before the weld broke. The weld probably broke after about 12-15 whacks with a 10lb sledge with a 3 foot handle. While performing the welds I hooked up an ammeter to the ground cable and it indicated that the welds were in the neighborhood of 300-310 amps. I am using .035" metal cored wire @ 675 wire feed speed @ 28.3 volts. I am coming up against the max capability of the welder soon, which is rated at 1/2" plate welds in a single pass.
So my questions are:
Is it typical to see 3/8" plate bend during a fillet weld break test? If so, does anyone know what the voltage and amp settings were to achieve that situation?
From my interpretation of the AWS fillet weld break test, the 3/8" welds I have done still would pass that test as it is "...showing complete fusion to the root of the joint with no inclusion or porosity larger than 3/32 in…" . Nevertheless, should I be concerned that I am not able to duplicate the same success as I had with the 1/4" plate?
Never one to rule out my poor welding skills please know that I always include that as a possibility...