Cobalt-Chrome Alloy Tribaloy T-800 GTAW
Finish state
UNS R30800
GTAW = bare cast rod / TIG hardfacing deposit, as welded
Manual repair overlays and small localized hardfacing where PTA equipment is unavailable; requires preheat to limit cracking.
Values for the GTAW condition
Other Tribaloy T-800 tempers and conditions
Tribaloy T-800 is listed in 5 conditions; see the grade overview at Tribaloy T-800.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Atmospheric plasma sprayed coating | Lower-cost sprayed coating for milder wear duty; more porosity and lower bond strength than HVOF. | — | 60 | 0.1 | 55 HRC | 0.9 % IACS |
GTAWThis page Bare cast rod / TIG hardfacing deposit, as welded | Manual repair overlays and small localized hardfacing where PTA equipment is unavailable; requires preheat to limit cracking. | 430 | 450 | 0.2 | 56 HRC | 1.7 % IACS |
ACDefault Spheroidize annealed | Standard supply condition for valve seats, bushings and nozzles machined to net shape by grinding. | 480 | 500 | 0.3 | 58 HRC | 1.7 % IACS |
Laser cladding deposit, as clad | Choose for low-dilution, fine-Laves-phase coatings with minimal HAZ and tight dimensional control. | 530 | 550 | 0.3 | 60 HRC | 1.7 % IACS |
Hot isostatic pressed | Use when a fully dense, fine and uniform Laves-phase structure with slightly better toughness than casting is required. | 560 | 600 | 0.5 | 57 HRC | 1.8 % IACS |
What is Tribaloy T-800 GTAW?
Tribaloy T-800 GTAW is Tribaloy T-800 supplied in the GTAW condition — manual repair overlays and small localized hardfacing where PTA equipment is unavailable; requires preheat to limit cracking. Tribaloy T-800 GTAW has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 96% of cobalt-chrome alloy grades. Elongation at break is 0.2% and the elastic modulus is 220 GPa (31.9 Msi). Tribaloy T-800 GTAW has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 63% of cobalt-chrome alloy grades. It melts at 1,250°C (2,282 °F). AC is the default condition FabDigit quotes; GTAW is available on request or by drawing note.
Limitations
- Limited ductility — 0.2%, worse than 100% of cobalt-chrome alloy grades
- Low strength — 430 MPa (62.4 ksi), worse than 96% of cobalt-chrome alloy grades
- Difficult to weld — 18/100, worse than 96% of cobalt-chrome alloy grades
- Low fracture toughness — 13 MPa·√m (11.8 ksi·√in), worse than 84% of cobalt-chrome alloy grades
- High embodied carbon — 16 kg CO₂/kg, worse than 84% of cobalt-chrome alloy grades
Tribaloy T-800 GTAW properties
Typical room-temperature values for Tribaloy T-800 GTAW; 21 are specific to this condition. Other listed values are Tribaloy T-800 reference data and may not represent this condition. Bars are the position among cobalt-chrome alloy grades.
Physical3
Tribaloy T-800 GTAW has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 63% of cobalt-chrome alloy grades. It melts at 1,250°C (2,282 °F).
Mechanical15
Tribaloy T-800 GTAW has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 96% of cobalt-chrome alloy grades. Elongation at break is 0.2% and the elastic modulus is 220 GPa (31.9 Msi).
Thermal5
Tribaloy T-800 GTAW is rated for continuous service to 800°C (1,472 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 82% of cobalt-chrome alloy grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Tribaloy T-800 GTAW conducts electricity at 1.7 % IACS, worse than 92% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (76/100), better than 50% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of Tribaloy T-800 GTAW takes about 170 MJ of energy and emits 16 kg of CO₂ — more than 63% of cobalt-chrome alloy grades. Typical recycled content is 25%.
Manufacturability7
Tribaloy T-800 GTAW's machinability is not recommended (3/100, worse than 100% of cobalt-chrome alloy grades); weldability poor (18/100); formability not recommended (1/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Tribaloy T-800 GTAW
Is Tribaloy T-800 easy to machine?
Not conventionally machinable — finish by grinding (CBN/diamond, SiC for roughing), EDM or lapping; leave 0.3–0.6 mm grind stock on overlays.
Can Tribaloy T-800 be welded?
Deposit only as hardfacing (PTA/GTAW/laser) with 200–400 °C preheat, slow cooling and thin passes; heavy single-pass layers crack readily and it is not a structural weld metal.
Can Tribaloy T-800 be formed, bent or molded?
Zero cold formability — parts are net-shape cast, HIP-consolidated or clad; all shaping must be done in the liquid or powder state.
What surface finishes work on Tribaloy T-800?
Grinding/lapping yields a hard, glossy sealing surface with excellent scratch and galling resistance; no plating or anodizing needed, and coatings are usually left as-ground.
Tribaloy T-800 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Moforms CoMoSi Laves phase | 26 – 30 | 28.5 |
| Cr | 16 – 19 | 17.5 |
| SiLaves-phase former | 3 – 3.8 | 3.4 |
| C | ≤ 0.08 | 0.05 |
| Ni | ≤ 1.5 | 0.5 |
| Fe | ≤ 1.5 | 0.5 |
| Cobalance, nominally ~48-52 % | balance | — |
Tribaloy T-800 GTAW — frequently asked
What is Tribaloy T-800 GTAW used for?
Tribaloy T-800 GTAW is typically used for severe abrasive wear surfaces, valve trim, hot extrusion tooling and thermal spray coatings. In short: hardest Tribaloy grade; laves-phase abrasion resistance; grind-only, very low ductility.
What is the yield strength of Tribaloy T-800 GTAW?
Tribaloy T-800 GTAW has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 96% of cobalt-chrome alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Tribaloy T-800 GTAW easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 100% of cobalt-chrome alloy grades). Not conventionally machinable — finish by grinding (CBN/diamond, SiC for roughing), EDM or lapping; leave 0.3–0.6 mm grind stock on overlays.
Can Tribaloy T-800 GTAW be welded?
Not readily — weldability is rated poor (18/100). Deposit only as hardfacing (PTA/GTAW/laser) with 200–400 °C preheat, slow cooling and thin passes; heavy single-pass layers crack readily and it is not a structural weld metal.
What surface finishes work on Tribaloy T-800 GTAW?
Grinding/lapping yields a hard, glossy sealing surface with excellent scratch and galling resistance; no plating or anodizing needed, and coatings are usually left as-ground.
Can Tribaloy T-800 GTAW be formed, bent or molded?
Zero cold formability — parts are net-shape cast, HIP-consolidated or clad; all shaping must be done in the liquid or powder state.
What is the maximum service temperature of Tribaloy T-800 GTAW?
Tribaloy T-800 GTAW is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Tribaloy T-800-AC and Tribaloy T-800-HIP?
AC is the default condition — standard supply condition for valve seats, bushings and nozzles machined to net shape by grinding. HIP: use when a fully dense, fine and uniform Laves-phase structure with slightly better toughness than casting is required. Yield strength is 480 MPa in AC versus 560 MPa in HIP.
Sources
- Tribaloy T-800 alloy data sheet — Kennametal Stellite / Deloro Wear Solutions (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (cobalt alloys) — ASM International (1990)
- UNS R30800 alloy designation (Metals & Alloys in the Unified Numbering System) — SAE/ASTM (2017)
- ASM Handbook Vol. 5A — Thermal Spray Technology (Co-Mo-Si wear coatings) — ASM International (2013)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.