We have a new set-up to our SAW machine for strip with a refurbished nozzle. We have not used strip before and we are having trouble getting the arc to start using constant voltage (CV) setting (the strip feeds through the nozzle very quickly but does not start an arc). We are using 0.5mm x 60mm strip (Stainless to Carbon Steel). We are able to get an arc with constant amperage (CA) settings on the SAW machine, however, the weld is not of the quality we would expect/want. It seems to be an inconsistent bead that is slightly concave with some little porosity. The strip/flux vendor has set parameters that the say to hold if at all possible which was our starting point and those parameters were devloped using CV. We are also talking to our SAW machine vendor to try to work it out if it's an electrical problem. I'm just looking for outside experiance to help me evaluate what they may come up with.
As I understand it, I think the CV should be preferred since the feedrate is adjusted to compensate for slight changes in voltage across the arc to keep the voltage constant. I would think it would help with our bead profile.
My question is if anyone knows if strip should be run using CV or CA and what the reason is for either case? What are possible reasons be for the arc not starting with CV?
