Universal No. 21 is a cobalt-chromium-molybdenum alloy designed for covered electrode, TIG, MIG, hard surfacing applications. The work-hardening characteristics, high ductility properties, excellent resistance to impact and metal to metal wear suit Universal 21 to severe applications where a work-hardening material is desired (as welded Rc 20; work hardened Rc 40-43).

Universal No. 21 applications include: high temperature valves, high pressure valves, hot punches crushing knives, drop forging dies, tap hole augurs, pump shafts and sleeves, press dies, vapor tight valve seats.

This alloy has the best impact resistance of the cobalt based alloys. Alloy 21 work hardens in service, has excellent erosion, corrosion and metal to metal wear resistance. Deposits exhibit effective hardness and a good cutting edge at high temperatures. On thick overlays Alloy 21 can be used as a buildup prior to depositing a higher hardness alloy.