Cobalt-Chrome Alloy Haynes 188-SA (Solution annealed)
Heat-treated state · default condition
UNS R30188 · EN 2.4683
Standard mill condition for combustor and hot-gas sheet metal; best ductility and formability.
Values for the SA condition
Other Haynes 188 tempers and conditions
Haynes 188 is listed in 3 conditions; see the grade overview at Haynes 188.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefaultThis page Solution annealed | Standard mill condition for combustor and hot-gas sheet metal; best ductility and formability. | 464 | 960 | 53 | 215 HB | 1.7 % IACS |
As-welded deposit | Reference condition for weld-joint design in fabricated combustor/duct assemblies without post-weld anneal. | 490 | 840 | 32 | 225 HB | — |
Cold worked | Pick for high-temperature springs, seals and fine wire where strength matters more than ductility. | 1,250 | 1,450 | 4 | 42 HRC | — |
What is Haynes 188-SA?
Haynes 188-SA is Haynes 188 heat treated to SA — standard mill condition for combustor and hot-gas sheet metal; best ductility and formability. Haynes 188-SA has a yield strength of 464 MPa (67.3 ksi) and a tensile strength of 960 MPa (139 ksi) — weaker than 85% of cobalt-chrome alloy grades. Elongation at break is 53% and the elastic modulus is 232 GPa (33.6 Msi). Haynes 188-SA has a density of 8.98 g/cm³ (0.324 lb/in³), heavier than 91% of cobalt-chrome alloy grades. It melts at 1,302°C (2,376 °F).
Advantages
- High service temperature — 1,095°C (2,003 °F), better than 100% of cobalt-chrome alloy grades
- Forms and bends easily — 65/100, better than 100% of cobalt-chrome alloy grades
- Readily welded — 75/100, better than 98% of cobalt-chrome alloy grades
- Ductile — tolerates forming and impact — 53%, better than 93% of cobalt-chrome alloy grades
Limitations
- High embodied carbon — 19 kg CO₂/kg, worse than 98% of cobalt-chrome alloy grades
- Poor heat conductor — 10.8 W/m·K (6.24 BTU/hr·ft·°F), worse than 93% of cobalt-chrome alloy grades
- Hard to polish — 70/100, worse than 91% of cobalt-chrome alloy grades
- Low strength — 464 MPa (67.3 ksi), worse than 85% of cobalt-chrome alloy grades
Haynes 188-SA properties
Typical room-temperature values for Haynes 188-SA; 20 are specific to this condition. Other listed values are Haynes 188 reference data and may not represent this condition. Bars are the position among cobalt-chrome alloy grades.
Physical3
Haynes 188-SA has a density of 8.98 g/cm³ (0.324 lb/in³), heavier than 91% of cobalt-chrome alloy grades. It melts at 1,302°C (2,376 °F).
Mechanical14
Haynes 188-SA has a yield strength of 464 MPa (67.3 ksi) and a tensile strength of 960 MPa (139 ksi) — weaker than 85% of cobalt-chrome alloy grades. Elongation at break is 53% and the elastic modulus is 232 GPa (33.6 Msi).
Thermal5
Haynes 188-SA is rated for continuous service to 1,095°C (2,003 °F). It conducts heat at 10.8 W/m·K (6.24 BTU/hr·ft·°F), worse than 93% of cobalt-chrome alloy grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
Haynes 188-SA conducts electricity at 1.7 % IACS, worse than 92% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 54% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of Haynes 188-SA takes about 280 MJ of energy and emits 19 kg of CO₂ — more than 100% of cobalt-chrome alloy grades. Typical recycled content is 30%.
Manufacturability8
Haynes 188-SA's machinability is poor (15/100, better than 79% of cobalt-chrome alloy grades); weldability very good (75/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Haynes 188-SA
Is Haynes 188 easy to machine?
Very difficult: work-hardening Co-W solid solution needs rigid setups, positive-rake carbide or ceramic tools, low speed/heavy positive feed and flood coolant to avoid glazing.
Can Haynes 188 be welded?
Readily joined by GTAW/GMAW/resistance and EB welding with matching 188 filler; keep heat input low, no preheat needed, solution anneal after heavy welding to restore ductility.
Can Haynes 188 be formed, bent or molded?
Good cold formability in the solution-annealed condition but forces are roughly double those for stainless; interstage anneal at ~1175 °C with rapid quench, hot work 1175–980 °C.
What surface finishes work on Haynes 188?
Not anodizable — pickle/grit-blast to remove oxide, then optionally aluminide diffusion or thermal-barrier coat for combustor service; polishes well to a bright hard surface.
Haynes 188 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 |
|---|---|---|
| Ni | 20 – 24 | 22 |
| Cr | 20 – 24 | 22 |
| W | 13 – 16 | 14 |
| Fe | ≤ 3 | 1.5 |
| Mn | ≤ 1.25 | 0.6 |
| Si | 0.2 – 0.5 | 0.35 |
| C | 0.05 – 0.15 | 0.1 |
| Larare-earth addition for oxide-scale adherence | 0.02 – 0.12 | 0.03 |
| B | ≤ 0.02 | — |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Cobalance, nominally ~39 % | balance | — |
Haynes 188-SA — frequently asked
What is Haynes 188-SA used for?
Haynes 188-SA is typically used for combustor liners, afterburner components, gas turbine hot sections, high-temp springs and furnace hardware. In short: best-oxidizing Co-Cr-W sheet alloy; 1095 °C service, weldable; tougher to machine than L605.
What is the yield strength of Haynes 188-SA?
Haynes 188-SA has a typical yield strength of 464 MPa (67.3 ksi) and a tensile strength of 960 MPa (139 ksi) — weaker than 85% of cobalt-chrome alloy grades. Strength varies by condition: see the 3 listed tempers.
Is Haynes 188-SA easy to machine?
Not especially — machinability is rated poor (15/100, better than 79% of cobalt-chrome alloy grades). Very difficult: work-hardening Co-W solid solution needs rigid setups, positive-rake carbide or ceramic tools, low speed/heavy positive feed and flood coolant to avoid glazing.
Can Haynes 188-SA be welded?
Yes — weldability is rated very good (75/100). Readily joined by GTAW/GMAW/resistance and EB welding with matching 188 filler; keep heat input low, no preheat needed, solution anneal after heavy welding to restore ductility.
What surface finishes work on Haynes 188-SA?
Not anodizable — pickle/grit-blast to remove oxide, then optionally aluminide diffusion or thermal-barrier coat for combustor service; polishes well to a bright hard surface.
Can Haynes 188-SA be formed, bent or molded?
Good cold formability in the solution-annealed condition but forces are roughly double those for stainless; interstage anneal at ~1175 °C with rapid quench, hot work 1175–980 °C.
What is the maximum service temperature of Haynes 188-SA?
Haynes 188-SA is rated for continuous use to about 1,095°C (2,003 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Haynes 188-SA and Haynes 188-CW?
SA is the default condition — standard mill condition for combustor and hot-gas sheet metal; best ductility and formability. CW: pick for high-temperature springs, seals and fine wire where strength matters more than ductility. Yield strength is 464 MPa in SA versus 1,250 MPa in CW.
Sources
- HAYNES 188 alloy brochure H-3001 — Haynes International (2020)
- ASTM B435 — UNS R30188 Sheet, Plate and Strip — ASTM (2017)
- ASTM B572 — UNS R30188 Rod — ASTM (2017)
- AMS 5608 / AMS 5772 / AMS 5801 — SAE International (2018)
- ASM Handbook Vol.2 — Properties of Cobalt-Base Superalloys — ASM International (1990)
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.