Fillet Weld Break Test

Date 03-25-2014 20:47

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... :lol:

By Lawrence (*****)

Date 03-25-2014 21:35 Edited 03-25-2014 21:39

If you have fusion at the root, you have succsess :)

The thicker plates should not bend over, they should fracture.

What may be of equal importence is your ability to produce a specific sized fillet in a single pass that is also acceptable to visual inspection criteria. These things will be controlled via WFS/Voltage relationship, gun angle and travel speed.

With the wire you are using you should be able to make a 3/16" a 1/4" and a 5/16" fillet weld that all pass the break test. Once your parameters are properly set, the only thing you should need to change is your travel speed. (assuming flat or horizontal positions) 1F or 2F

You don't mention your gas mixture so it's difficult to judge your voltage, although it appears a bit high to me.

Also your wire feed speed (WFS) is at the high side for .035 MCAW.... As a beginner you can slow that down to about 500 ipm and 27 volts to allow more *think time* as you place your weld and learn to read the puddle... Higher feed rates can be used in production once you learn your way around the process.

The actual arc length (distince from the unmelted electrode wire to the work) should be short.. Less than 1/8"...... A good way to go is to start at 27 volts and decrease by 1/2 volt incraments until you see slight spatter, than increase until spatter is gone. Too high voltage and the longer arc associated with it causes undercut on fillets.

A 5-15 degree push gun angle is usually recommended for spray transfer MCAW. Keeping the electrode wire pointed directly at the leading edge of the puddle with no whipping back or side to side motion... Just a straight push. Edit: Weld size determined by travel speed from point A to point B

By kung fu panda (*)

Date 03-26-2014 02:44 Edited 03-26-2014 02:47

Lawrence,

Thank you. That is great to know and great additional info. BTW, I am using 98% argon 2% oxygen with GMAW.
Again thanks!