Carbide is used on end mills alot. Looks like a drillbit but flat on the end with a star shaped cutter. Another really good source of this is gages. If you can get big plug gages from factories used to inspect metal parts with it's a gold mine.

Carbide is a darker gray than steel and you can tell it by looking at it. Look almost like it's coated in graphite.

I'd also sell it on ebay than to your local yard. If you check metalsmarket it goes for like $7.00 / lb.