eBay is another good resource for smaller pieces of heavy cord, cut from a bulk spool. I’ve got SJO, SEO, SJEOW, etc. cords and I’ve never noticed an appreciable difference in long term durability. Reference the McMaster chart shown above, one is only rated for 300V and there’s one with a neoprene cover that tends to pick up more dirt.
Most important is to match ampacity, especially as your device, unlike a welder, will run continuous. I don’t do so, but I know plenty of guys who’ll “de-rate” their cords for welding use. Their thoughts are that even IF they wind up drawing the full amperage the machine can use, they’re not doing it anywhere close to full-time. Even still I would go no smaller than 8/3 or 8/4
As noted, I assume your device to consume 49 amps@208V and 44 amps@240V.
No less than 6/3 or 6/4 AWG here. Especially if you use the device regularly or for long periods.
I actually really don’t like the Hubble straight-blade, 50A three or four-pin plug ends. I’ve used these plugs for welding service and they don’t tend to last long. Most of my welding cords now sport a deep, metal gang-box with receptacle and a wire strain relief:
The cost is a little bit higher initially, but seems cheaper in the long-run as it will survive the most things shy of being run over by a fork lift.
For your application I would also recommend changing all the plugs in the circuit to a twist-blade plug. Making a 44 or 49 amp “hot-stab” isn’t a pretty thing. It’s seems extra likely in your situation though. Unless the oven has safety circuitry, chances are it stays on and wanting full amperage the moment the circuit gets reconnected. Also seems likely as not that the oven main power will get turned off before investigations lead the user to the unplugged cord.
The twist-lock plug ends are a bit more expensive and if you take my advice you’ll be buying an additional plug and receptacle. If cost becomes too much of an issue, spring for an extra strain-relief instead and run the cord from a junction/gang-box instead. No way another guy working can unplug that...
Be safe and stay healthy
Jeremy.