The rule, or rules in this case, are specifically -

12.3 Rotating Weapons
The speed of any rotating weapons - e.g. circular saws, carbon or steel cutting discs - must not exceed the
manufacturer's specification. The manufacturer's specification must be available for inspection.

12.4 Hardened Blades
Commercially manufactured, hardened steel blades that may shatter are not allowed.

So far as I know there would only be 2 types of commercial blade permitted -

Friction Saw Blades - http://sheffsaws.com/circular-saws/friction-saw/ - The same type that Dead metal used. All 1 piece with a hardened edge. Expensive!

Diamond Abrasive - http://www.screwfix.com/p/erbauer-se...0-x-20mm/32833 - These are 1 piece of metal with an abrasive powder glued to the surface. Rather than shattering the abrasive section would turn almost to dust.

However, since I am pretty sure you would bust a commercial blade every fight I would recommend getting a disc custom cut from Hardox or another type of wear steel. This would only only be more effective but cheaper. I can work with you to design one to fit your needs and there are many other people out there with access to CAD as well.