Cobalt #1 - Coated Electrodes, bare rods, and welding wires
Hardness: 50-55 Rc
AWS A5.13 RCoCR-C (bare) ECoCr-C (coated)
Mil R-17131, Type MIL-RCoCr-C-1 are available also.
A cobalt based alloy with outstanding resistance to abrasion, heat and
corrosion. This alloy has a low coefficient of friction and acquires a
high polish in service. This alloy is not recommended in applications
involving impact or where crack-free weld deposits are required.
General uses include the overlay of extrusion screw conveyors, valve
stems and bearings.
Cobalt #6 - Coated Electrodes, bare rods, and welding wires
Hardness: 40-45 Rc
AWS A5.13 RCoCr-A (bare) and ECoCr-A (coated)
Mil R-17131, Type MIL-RCoCr-A-1, and AMS 5788
are available also.
This is the most generally used cobalt alloy, having excellent resistance
to many forms of mechanical and chemical degradation over a wide
temperature range. This alloy exhibits high tensile strength, metal to
metal wear, corrosion and erosion properties. It is ideally suited to a
variety of hardfacing processes. Uses include overlays on valves, hot
shear blades, punches, and chain-saw bars. Bonds well with weldable
alloys steels, including stainless.
Cobalt #12 - Coated Electrodes, bare wires and welding wires
Hardness: 48-52 Rc
AWS A5.13 RCoCr-B (bare) and ECoCr-B (coated)
Similar to Cobalt #6 in composition with the difference between
the alloys being one of carbide volume, therefore high hardness and
resistance to abrasion. Overlays resist abrasion, corrosion and mod-
erate impact and acquire a high polish in service. Uses include over-
lays on screw conveyors and augers in the rubber and plastic industry,
engine components for gas and diesel engines, and extrusion screws
and various valves.
Cobalt #21 - Coated Electrodes, bare wires and welding wires
Hardness: 33-36 Rc as welded, work hardens to RC 45+
Specification: UNS-R30021
The least crack-sensitive of all the cobalt based alloys. This alloy, a low
carbon, molybdenum strengthened cobalt-chromium alloy will work
harden to Rc 45+ with excellent impact and metal to metal wear qual-
ities, especially at high temperatures. Uses include overlays in hot
extrusion and forging dies, trimmers, punches and hot shear blades.
All of the above listed cobalt materials are available in spools, cut lengths and covered electrodes.
