I finally found a picture of a set of spinning pliers I want to copy. I'm not sure what steel will work the best. For my drag tools I use 4140. These tools are thick and blunt. The pliers will be thin but need to have outstanding abrasion resistance and be a little flexible in the handle yet very stiff in the jaws.

Seems to me like 4140 would do fine for you but if you want to upgrade a bit 4150 is said to be significantly tougher.

One of the things we played around with was to clad the wear surfaces of tools with either hard face rod or some other wear resisting weld rod that was carbide bearing.We used to reface or build hammer mills,extrusion dies and other foundry and extrusion power and hand tools.We also tried a stellite rod but that was too much trouble for anything but the high dollar work.
The types we were using were available in either TIG or MIG wire and we almost tripled the life of some tools like extrusion dies and the dreaded hammer mill.
After welding the preferred way to blend and smooth was to forge and planish.Final polish required diamond abrasives.
You might want to look at some of the rods they use to build back turbine rotors too.Mostly TIG work but when finished they will withstand heat and wear (obviously).

Be prepared for sticker shock!The good thing is that a little goes a long way.