Metco 32C is the 80% tungsten-carbide nickel-matrix spray-and-fuse powder — the highest WC loading in Oerlikon Metco's self-fluxing-with-hardphase family. Twenty percent NiCrBSi self-fluxing matrix, eighty percent WC-12Co hard-phase grains. Flame-sprayed, then torch- or induction-fused at around 1,900°F into a dense, metallurgically bonded carbide matrix.

The reason to pick 32C over its lower-loaded cousin Metco 31C-NS (35% WC) is service severity. When the abrasion is extreme — drill-pipe tool joints rubbing rock, slurry-pump impellers moving silica and ore, mining screens beating on coarse feed — 32C's 80% carbide loading moves the needle on coating life. We run it where HVOF WC-Co isn't practical: when the part needs more than 25 mils of protection, or when a fused metallurgical bond beats a mechanical as-sprayed one.

The trade-offs are real. 80% carbide means a crack-sensitive deposit on thick builds — we cap single-pass at 2 mm, preheat, and slow-cool. Material cost runs multiples of plain NiCrBSi. Service tops at ~950°F before WC decarburizes. Impact loading will chip it — this is an abrasion-first coating, not a shock-first one.

Drill-pipe hardbanding, slurry-pump internals, mining wear plates, cement raw-mill tips, frac-pump fluid ends, tillage points — if the part dies from abrasion and you need thicker protection than HVOF WC-Co can give you, Metco 32C earns the job. Send the sketch; we'll spec the process.

Technical data

Hardness: ~950-1,100 HV fused composite macrohardness (matrix ~62 HRC ≈ 740 HV; embedded WC-Co grains ~75 HRC equivalent / ~1,350+ HV); fused composite sits well above Metco 31C-NS (35% WC) and well above unfilled NiCrBSi alloys
Hardness (HRC): 62 HRC fused matrix macrohardness; 75 HRC equivalent on embedded carbide grains (tungsten carbide hard phase)
Bond strength: Metallurgically bonded after fusing — substrate-limited, not coating-limited; post-fuse interface is a true fusion diffusion zone, same bond class as Colmonoy spray-and-fuse overlays (typical >10,000 psi pull-test pulls substrate, not coating)
Max service temp: ~950°F continuous; above that WC decarburizes to W₂C and the nickel-boride matrix softens
Max service temp: ~510°C continuous
As-sprayed porosity: As-sprayed 3-8% (typical flame-spray deposit before fuse); after fuse cycle <1%, virtually porosity-free and metallurgically bonded
Typical thickness: 15-60 mils (0.4-1.5 mm) typical; 80 mils (2.0 mm) practical upper limit — thicker builds are crack-prone due to 80% carbide loading and ~20% fuse shrink
Density: ~13.9 feed powder; ~12.5-13.0 fused deposit

Where it earns its keep

80% tungsten-carbide hard-phase loading — abrasion and erosion life approaches pure WC-Co HVOF coatings, but in a self-fluxing, metallurgically bonded, spray-and-fuse package
Self-fluxing matrix means a true fusion bond on thick builds — no separate flux, no shielding gas, and no mechanical-adhesion limit like as-sprayed WC-Co
Significantly more abrasion-resistant than Metco 31C-NS (35% WC) — the 80% loading is the pick when wear service is extreme and coating life is the buy decision
Handles thicker builds than pure HVOF WC-Co (HVOF caps around 20-25 mils practical; Metco 32C routinely lays 40-60 mils of fused, bonded carbide matrix)
Flame + HVOF both qualify — HTS can spray 32C in the field with a flame-spray rig and an induction fuse, or shop-apply it under HVOF for a denser, finer-grained as-sprayed coating
Lower applied cost per square-inch-year than running pure WC-Co HVOF on parts that need 40+ mils of protection

Where it doesn't

Expensive — tungsten carbide is the price driver; 80% WC loading means the material cost per pound is multiples of plain NiCrBSi or Metco 31C-NS
Crack-sensitive on thick builds — the 80% carbide loading reduces matrix ductility, and fuse shrink (~20%) plus thermal gradient can open checking cracks; preheat, slow cool, and thickness discipline (keep under 2 mm single-pass) are mandatory
More crack-prone than Metco 31C-NS (35% WC) for the same reason — when the duty can be met at 31C's hardness, 31C gives up less toughness
Service-temperature capped at ~950°F — above that, WC decarburizes (WC → W₂C + W) and the nickel-boride matrix softens; for hotter service step to a chromium-carbide or an MCrAlY overlay
Not the pick for impact or shock loading — the brittle WC-Co hard phase and boride-carbide matrix will chip under ballistic or pounding service; consider a cobalt-base Stellite overlay where impact dominates
Fusing the coating requires the part to survive a 1,850-1,950°F thermal excursion without distortion — thin-wall assemblies and close-tolerance geometry may need an alternate process (HVOF as-sprayed)

Which process, when?

Flame spray + fuse is the classic route for Metco 32C — powder is flame-deposited, then torch-, induction-, or furnace-fused at ~1,900°F. This delivers 40-60 mils of metallurgically bonded, sub-1% porosity carbide matrix on drill-pipe hardbands, pump impellers, and chute liners. HVOF skips the fuse step and lays down a denser as-sprayed coating (finer microstructure, less WC dissociation) when the part can't take fuse heat or when tighter tolerances demand it — but max thickness tightens to ~20-25 mils. Pick flame-and-fuse when the duty is thick protection on a geometry that tolerates the thermal cycle; pick HVOF when part distortion or heat-input is the constraint.

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.

Oerlikon Metco DSMTS-0077.4 — Nickel-Based Self-Fluxing Alloys with Hard Phase (Metco 31C-NS, Metco 32C)
“Metco 31C-NS and Metco 32C consist of a self-fluxing alloy blended with a hard phase constituent of tungsten carbide in a gas atomized nickel matrix. Metco 31C-NS contains 35% hard phase WC; Metco 32C contains 80% hard phase WC. Matrix composition Ni 70, Cr 17.5, Fe 4, Si 4, B 4, C 0.5. Hard phase 88 WC / 12 Co. Applied by thermal spray and fused to develop a dense coating with minimal porosity and oxides, metallurgically bonded to the substrate. Resistant to abrasive grains, hard surfaces, fretting and particle erosion.”
Oerlikon Metco DSM-0265.2 — Nickel-Based Self-Fluxing Alloys with Hard Phase
“Tungsten Carbide – Nickel Chromium Self-Fluxing Powders for thermal spray followed by a fuse cycle; Metco 32C provides the highest wear resistance in the self-fluxing-with-hardphase family at 80% WC loading, with a fused matrix macrohardness of 62 HRC and embedded carbide macrohardness of 75 HRC.”
Oerlikon Metco Thermal Spray Materials Guide
“Metco 32C: coarse grey powder consisting mostly of tungsten carbide and cobalt with a nickel-chromium-boron-silicon self-fluxing matrix; nominal particle size -125 +45 µm; spheroidal morphology improves flowability in flame spray; highest wear resistance among self-fluxing hardfacing alloys with tungsten carbide; designed to be post-coat fused.”
Characterisation of Spheroidised Tungsten Carbide Metco 32C Powder Using Radio Frequency Plasma
“Metco 32C feed-powder XRD shows WC (93%) and W₂C (7%); density 13.91 g/cm³ untreated; above ~500-600°C WC dissociates toward W₂C with corresponding decarburization — consistent with a ~950°F practical service temperature limit in fused-coating use.”
Oerlikon Metco — Self-Fluxing and Self-Fusing Alloys for Dense Coatings
“Self-fluxing alloys are nickel- or cobalt-based powders with boron and silicon that scavenge oxides during the post-spray fuse cycle; hard-phase variants (with WC, Cr₃C₂, or carbide blends) are selected for the highest abrasion and wear resistance; fusing temperature typically 1,000-1,100°C.”
Oerlikon Metco Joining & Cladding — Stabilizers, Roller Reamers and Drill Collars
“Wear protection for oil and gas drill-string components — drill collars, stabilizers, and roller reamers — uses nickel-matrix tungsten-carbide overlays and hardbanding to resist three-body abrasion and fretting against casing and open-hole formations.”
Kermetico — Erosion-Abrasion Resistant Coatings for Slurry Pump Impellers and Backing Plates
“Tungsten carbide in combination with cobalt, nickel, or cobalt-chrome matrices is preferred for slurry pump protection; thicker builds of nickel-matrix WC blends are used where HVOF thickness limits (20-25 mils) are insufficient for service life.”
Materials Today: Proceedings — Improving Drill Pipe Durability by Wear-Resistant Surfacing
“Nickel-based tungsten-carbide hardbanding overlays significantly extend drill-pipe tool-joint life against abrasion and casing-friendly wear; hardness and WC loading of the overlay are the dominant variables governing service interval.”

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.

Metco 32C

Technical data

Where it earns its keep

Where it doesn't

Typical applications

Wear modes addressed

Industries

Substrates

Which process, when?

Sources

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