HTS Coatings — machining & grinding

Stellite 1

30% Cr, 13% W, 2.5% C, Fe, Ni, Mo, Mn, Si, Co-balance

  • Flame
  • HVOF
  • Spray & Fuse

Stellite 1 is the hardest member of the Stellite family — a Co-Cr-W-C alloy packed with chromium-rich M7C3 primary carbides. Kennametal publishes 50-58 HRC / 550-720 HV, density 8.69 g/cc, and hardness retention above 1400°F. That carbide volume is what buys the performance: extreme low-angle erosion, high-stress gouging abrasion, mineral slurries, and filled-polymer extrusion all eat Stellite 6 faster than they eat Stellite 1.

The trade-off is ductility. Stellite 1 is the most crack-sensitive grade in the family, and every reputable supplier says so out loud. Weld overlay demands preheat, interpass control, and slow cool; single heavy passes are how deposits split. That's why we reach for Stellite 1 only when Stellite 6 has been proven too soft for the service — crusher hammers, dredger teeth, oil-sands excavator buckets, screw extruders running heavily filled compounds, pump sleeves in bad slurry, and severe-service valve trim where solids chew through a standard deposit.

At HTS we run Stellite 1 across flame spray, HVOF, spray & fuse, and PTA/TIG weld overlay — matching process to part geometry, thermal mass, and service load. Finish is grind-only; plan for it.

Got a part that's outliving Stellite 6 but still wearing too fast? Send us the failed component — we'll tell you whether Stellite 1 is the right step up or whether you need a tungsten-carbide composite instead.

Technical data

Hardness
550-720 HV as-deposited (Kennametal datasheet); HVOF test work commonly averages ~718 HV
Hardness (HRC)
50-58 HRC (Kennametal); 51-60 HRC weld-deposit range per AWS ERCoCr-C; 51-56 HRC typical TIG/oxy-acetylene rod deposit
Bond strength
HVOF bond comparable to other Co-Cr-W alloys (~9,000-10,000 psi / 60-70 MPa substrate-limited); weld overlay metallurgically bonded when crack-free
Max service temp
Retains useful hardness above 1400°F; oxidation-limited in continuous air service
Max service temp
Hardness retention above 760°C; useful wear service to ~800°C depending on load and atmosphere
Typical thickness
Flame spray 10-25; HVOF 5-20 (dense, sub-2% porosity); Spray & Fuse 20-60; PTA/GTAW weld overlay 40-120 — thin single-pass layers preferred to control cracking
Melting range
2278-2450°F (supplier ranges vary from 1248-1345°C depending on heat)
Density
8.69

Where it earns its keep

  • Hardest as-deposited alloy in the Stellite family — 50-58 HRC / up to 720 HV — when Stellite 6 isn't hard enough to hold a gouging edge
  • Highest primary-carbide volume of the common Stellites, purpose-built for extreme low-angle erosion and severe three-body abrasion
  • Retains hardness above 760°C (1400°F) — outperforms WC-Co coatings that decarburize in the same temperature window
  • Corrosion resistance comparable to Stellite 6 in oxidizing and wet-sulfide service — you don't give up chemistry to get hardness
  • Applies via flame spray, HVOF, spray & fuse, PTA, and TIG — same process toolkit as Stellite 6, so we can match the part and the service

Where it doesn't

  • Very crack-sensitive — Kennametal and every reputable supplier flag Stellite 1 as more crack-prone than 6 or 12. Weld overlay requires preheat, tight interpass control, and slow cool; single heavy passes are the fastest way to split a deposit
  • Low ductility — poor choice for service that combines abrasion with heavy impact or thermal shock. If the part sees hammer-blow loading without a tough substrate backing, Stellite 12 or a WC composite is usually the safer call
  • Finish by grinding only — too hard to machine with carbide tooling. Plan fixturing and grind-stock accordingly
  • Premium alloy on a volatile cobalt market — most jobs that can run Stellite 6 should. Specify Stellite 1 only when Stellite 6 has been proven to fail on abrasion, not as a default upgrade

Typical applications

  • Crusher hammers and impactor bars in aggregate and cement plants
  • Dredger cutter teeth and suction-dredge wear shrouds
  • Screw extruders processing highly filled / glass-reinforced polymer compounds
  • Oil-sands excavator and bucket-wheel teeth (Athabasca-type service)
  • Mill liner lifter bars and ore-handling chute plates
  • Pump sleeves, wear rings, and expeller / impeller wear pads in high-abrasion slurry service
  • Rotary seal rings and bearing sleeves where Stellite 6 won't hold hardness
  • Severe-service valve trim (choke, control) in sand-laden or solids-carrying streams

Wear modes addressed

  • Severe three-body and two-body abrasion (sand, ore, mineral fillers)
  • Low-angle particle erosion (the condition Stellite 1 is designed for)
  • High-stress gouging abrasion on crusher / excavator contact faces
  • Slurry erosion-corrosion in mining and oil-sands service
  • Retained hardness at elevated temperature — resistant to softening up through 1400°F

Industries

  • Mining and aggregate (crushing, grinding, conveying)
  • Oil sands and heavy-oil upstream
  • Dredging and marine construction
  • Plastics / rubber compounding — twin-screw and single-screw extrusion of filled polymers
  • Cement and minerals processing
  • Pulp & paper chipper and refiner wear parts
  • Power generation (steam-turbine blade leading-edge shields in erosive service)
  • Oil & gas — choke and control-valve trim in sand-producing wells

Substrates

  • Carbon and low-alloy steels (1018, 4140, 4340) — the workhorse substrates for crusher, mill, and excavator parts
  • Martensitic stainless (410, 420) — valve trim and pump sleeves
  • Tool steels (H13) for hot-wear dies
  • Cast irons — with stringent preheat and buffer-layer practice
  • Austenitic stainless — less common, dilution control critical
  • Ni-base alloys — specialty valve trim in the harshest service

Which process, when?

Flame spray lays down 10-25 mil of Stellite 1 for light wear restoration on pump sleeves and seal rings where the part can't take weld heat. HVOF is the modern choice for dense, sub-2% porosity Stellite 1 on valve trim, pump components, and turbine leading edges — test work reports ~718 HV averages. Spray & Fuse (flame spray followed by torch or furnace fuse) gives a metallurgically bonded Stellite 1 layer 20-60 mils thick without the full heat-input of welding — a strong compromise for mill liners and pump wear rings. PTA and TIG weld overlay put down 40-120 mil fused deposits for crusher hammers, dredger teeth, and excavator teeth — but only with disciplined preheat, interpass temperature control, and slow cool. Thin, multi-pass deposits almost always beat a single heavy pass with Stellite 1.

Sources

Data points on this page draw on the following published references. Nothing here replaces a material-specific review by our process engineers — but it's the working starting point.

Material data on this page is provided as a general reference and can vary by lot, substrate, and application. Contact HTS to confirm the right material and specification for your specific part.

Thinking about Stellite 1 for a part?

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