Here are some examples of what happens to a weld when it does not make complete penetration into the work piece, wrong speed/amps/volts, and was possibly “wet bathed”.
Cracks on the outside edges of the weld bead is cause mainly because of lack of penetration. Basically the “welder” did not put either enough heat into the weld or went to fast while welding. As a result the weld bead sits on top of the work piece instead of penetrating all the way through and fusing with the work piece.
Cracks down the center of the weld bead are caused by either not cleaning the work piece well enough before welding, laying multiple welds on top of each other and not cleaning each weld of slag before laying the next weld bead down, or simply using the wrong filler rod/wire for the job. Also can be caused by “wet bathing” the weld…basically dipping the work piece into cold water right after laying a weld bead, which causes the weld to cool down rapidly and become too brittle.
Suggestions to prevent this from occurring.
1. Clean the work piece
2. Clean the welds before laying another one on top
3. Do not “wet bath” the weld
4. Make sure you have the right Amps and Volts set up for the work piece that you are about to weld on
5. Make sure you are going at the correct speed for the weld to make complete penetration
If you aren’t sure where to set your amps or volts and what speed you should be welding at you can always lay a bead on a similar piece that’s off to the side. This would be known as “scrap material”. Unless you are an experienced welder I would suggest continuing using scrap material to practice on before laying a bead on a nice set of headers.