Hobart welding rods

[manofsteel]

While I was at the local welding store. I asked the salesperson the differance between the 6013 447A and the 6013 447C. The 447C states it has a "soft arc" and suitable for "low open-circuit voltage AC machines. Perhaps Rock or someone could enlighten me on the differance. I have an old Hobart engine drive AC machine.

Thanks
Walt

[dseman]

Typically an electode has a differing flux composition for a 'low ocv' rating. This is intended to provide a better starting and reliable arc to be used by machines with a low ocv at the given amperage you will be operating at. Manufacturer's typically use anything below 50v as the threshold of denoting a 'low ocv' electrode. Most low ocv boxes are the lincoln 225 or 300amp ac buzz boxes. There ocv is only really good at low amperages. Each manufacturer usually posts this in their manuals. Also, low ocv rods generally have a reduced cvi or charpy-v-notch impact rating if that is important to you. Though 6013 is not a good choice for impact strength anyways. If your machine can show > 50 or 60 OCV at the given operating point of interest, then I would choose the non low ocv type. It is a better metallurgical choice.
-dsem****

[Ed Heimbach]

If you are running an engine driven machine, it is easy enough to raise the OCV, all you need to do is raise the engine rpm.
If you can get a higher voltage you can draw an arc out further, thus making it 'softer'.
Be advised that I'm only talking a few hundred rpm, to much and you remove the volt-amp curve too far from the designed parameters, and the arc per formance will be worse.

[manofsteel]

Thanks Dseman & Ed...that clears up some issues. Next time I have the engne drive going I will give that a try to raise the rpm and see if their is any difference