Does anyone here have experience using a pulsed GMAW process on P4 (Gr. 11, 12) material?
Using Lincoln equipment and running a downhill technique, we were unable to get a porosity-free weld using ER80s-B2 wire and a 90/10 Ar/CO2 mix.
When running the same process and comparable parameters on carbon steel with ER70s-6 wire, we could achieve perfect welds every time.
However, once the ER80s-B2 wire was used, we could not achieve a sound weld any time we ran over previous passes. No problems with an open root, but any time we pass over existing weld metal, even when ground/smoothed to bright, clean metal, we get porosity that is not open to the surface. We see it sporadically where the weld interfaces with the previous weld metal, and other times right in the middle of the weld bead. When running an open root pass, we did not see any porosity in that part of the weld, but would see porosity/inclusions when back grinding and welding the other side, or when welding the hot and fill passes.
We got the same results in the flat position, trying the ER80s-B2 wire on both carbon steel plate, and the P4 plate. We tried different heats of wire, different manufacturers, different gas bottles, different torch angles, different pulse wave forms, different flow rates, different interpass temperatures, different cleaning techniques... none of which eliminated the porosity/inclusions.
Needless to say, I'm baffled as to what the cause of this may be. Does anyone have any suggestions or input?
Using Lincoln equipment and running a downhill technique, we were unable to get a porosity-free weld using ER80s-B2 wire and a 90/10 Ar/CO2 mix.
When running the same process and comparable parameters on carbon steel with ER70s-6 wire, we could achieve perfect welds every time.
However, once the ER80s-B2 wire was used, we could not achieve a sound weld any time we ran over previous passes. No problems with an open root, but any time we pass over existing weld metal, even when ground/smoothed to bright, clean metal, we get porosity that is not open to the surface. We see it sporadically where the weld interfaces with the previous weld metal, and other times right in the middle of the weld bead. When running an open root pass, we did not see any porosity in that part of the weld, but would see porosity/inclusions when back grinding and welding the other side, or when welding the hot and fill passes.
We got the same results in the flat position, trying the ER80s-B2 wire on both carbon steel plate, and the P4 plate. We tried different heats of wire, different manufacturers, different gas bottles, different torch angles, different pulse wave forms, different flow rates, different interpass temperatures, different cleaning techniques... none of which eliminated the porosity/inclusions.
Needless to say, I'm baffled as to what the cause of this may be. Does anyone have any suggestions or input?
