Technical guide · 2026-08-14
Wear-Resistant Cobalt Alloys
Wear-resistant cobalt alloys are selected as cast parts, rods or hardfacing deposits for galling, erosion and hot wear; deposit dilution, cracking tolerance and finish geometry can control service more than nominal filler chemistry.
01
Definition and boundary
Covers Stellite-type bulk and deposited wear alloys; excludes cobalt-base creep alloys and cobalt-bonded hardmetals.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Chromium carbides resist abrasion.
Cobalt matrix retains hot hardness.
Tungsten or molybdenum adjusts wear and toughness.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| Alloy 6 | General wear/galling cobalt alloy. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| Alloy 12 | Higher-carbide abrasion emphasis. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| Alloy 21 | Tougher Co-Cr-Mo wear/corrosion balance. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
04
Properties and trade-offs
Galling resistance
Hot hardness
Erosion and corrosion-wear balance
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Valve seats
- Hot shear surfaces
- Pump and extrusion wear parts
Properties and trade-offs
- Identify wear mechanism.
- Select bulk versus overlay route.
- Limit hardness where impact occurs.
07
Fabrication, durability and inspection
Qualify preheat and cooling.
Control overlay dilution and bead placement.
Grind without thermal cracking.
08
Procurement checklist
- State bulk, PTA, laser or weld-deposit route.
- Define deposit dilution, thickness and crack acceptance.
- Specify hardness map, finish and bond/NDT tests.
09
Standards, sources and review
Standards and designation context
- Applicable ASTM or ISO product scope
- Buyer drawing and service qualification
- Agreed inspection and certification plan