Haynes 188 · UNS R30188 · W. Nr. 2.4683
Haynes 188 (R30188): composition, properties, fittings and flanges
Haynes 188 (R30188, W. Nr. 2.4683) is Solid-solution strengthened cobalt-nickel-chromium-tungsten alloy. Haynes 188 is specified at Cobalt Balance, Nickel 20.0 - 24.0, Chromium 20.0 - 24.0. Haynes 188 is a cobalt-base sheet alloy with the strength of a nickel superalloy but better resistance to sulphur-bearing hot corrosion,…
- UNS
- R30188
- W. Nr.
- 2.4683
- Density
- 9.14 g/cm³ (0.330 lb/in³)
- Key strength
- 860 MPa / 125 ksi
Identification and standards
| Short form | Haynes 188 · UNS R30188 · W. Nr. 2.4683 |
|---|---|
| Classification | Solid-solution strengthened cobalt-nickel-chromium-tungsten alloy |
| UNS | R30188 |
| Werkstoff number | 2.4683 |
| Material family | High-Temperature Alloys / Superalloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Cobalt (Co) | Balance | Matrix |
| Nickel (Ni) | 20.0 - 24.0 | Austenite stability and ductility |
| Chromium (Cr) | 20.0 - 24.0 | Oxidation and hot corrosion resistance |
| Tungsten (W) | 13.0 - 15.0 | Solid-solution strengthening |
| Iron (Fe) | 3.00 max | Residual |
| Carbon (C) | 0.05 - 0.15 | Carbide strengthening |
| Lanthanum (La) | 0.03 - 0.15 | Scale adhesion |
| Manganese (Mn) | 1.25 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 860 MPa / 125 ksi |
|---|---|
| 0.2 % yield strength, min | 380 MPa / 55 ksi |
| Elongation in 2 in, min | 45 % |
| Typical hardness, annealed | 190 - 240 HB |
| Useful continuous service temperature | About 980 °C |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 9.14 g/cm³ (0.330 lb/in³) |
|---|---|
| Melting range | 1300 - 1360 °C (2370 - 2480 °F) |
| Modulus of elasticity | 207 GPa (30.0 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 10.4 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 12.4 µm/m·°C |
| Specific heat capacity | 405 J/kg·K |
Specifications by product form
| Forgings & flanges | AMS 5772 / ASTM B564 family (UNS R30188) |
|---|---|
| Butt weld fittings | To order against AMS 5772 chemistry |
| Seamless pipe & tube | To order |
| Plate / sheet / strip | AMS 5608 |
| Bar / rod | AMS 5772 |
| Welding consumables | Matching Haynes 188 filler or ERCoCr-A |
| UNS / EN / China | UNS R30188 · W. Nr. 2.4683 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Combustor liners, afterburner parts and spray bars
- Transition ducts and hot gas path sheet structures
- Furnace retorts exposed to sulphur-bearing atmospheres
- Aero-engine and land turbine oxidation shields
Welding, forming and machining
- Welding
- Weld with matching filler by GTAW. Cobalt alloys are prone to hot cracking at high restraint, so use low heat input and ductile filler.
- Heat treatment
- Solution anneal at 1150 - 1230 °C and rapid cool.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Haynes 188 from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.