A high-performance cobalt-based superalloy, Alloy 188 is engineered for superior mechanical strength and oxidation resistance in extreme environments up to 1093°C.
Alloy 188 (also known as Haynes 188 or HS 188) is a solid-solution strengthened cobalt-nickel-chromium alloy enhanced with tungsten and lanthanum for exceptional strength and oxidation resistance at high temperatures. Designed for the aerospace, power, and turbine industries, it resists thermal fatigue, sulphate-deposit hot corrosion, and oxidising combustion gases.
This alloy maintains high ductility even after long-term exposure, offering excellent weldability, fabricability, and mechanical integrity in prolonged high-stress conditions. HS 188 performs reliably in aggressive environments where both heat and corrosion are at play.
We stock alloy 188 in a variety of product forms to suit different applications and fabrication methods, including plate, round bar, sheet, and welding wire. To view available sizes and submit an enquiry, use the dropdown selector below.
The following elements in Alloy 188 provide its distinctive balance of high-temperature performance and corrosion resistance.
| % | Cr | Ni | Co | W | La | B | C | Fe | Mn | Si | P | S |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 20 | 20 | - | 13 | 0.02 | - | 0.05 | - | - | 0.2 | - | - |
| Max | 24 | 24 | Balance | 16 | 0.12 | 0.015 | 0.015 | 3 | 1.25 | 0.5 | 0.02 | 0.015 |
Alloy 188 is engineered for service in extreme conditions involving heat, combustion by-products, and mechanical load. Key physical and thermal properties include:
Haynes Alloy 188 (UNS R30188) is an industry standard for high-temperature service in oxidising and corrosive gas streams, particularly in aerospace and energy generation markets.
It was originally developed to offer an optimal balance between:
The inclusion of lanthanum in the alloy improves oxide scale adherence at high temperatures, while tungsten contributes to solid-solution strengthening.
Welding can be carried out using GTAW (TIG), GMAW (MIG), resistance welding, or electron beam welding methods. Fabricated components benefit from annealing to optimise ductility and performance.
| Mechanical & Physical Properties | 21°C | 427°C | 538°C | 649°C | 760°C | 871°C | 982°C | 1093°C |
|---|---|---|---|---|---|---|---|---|
| Ultimate Tensile Strength /MPa | 944.6 | - | - | 710.2 | 620.5 | 413.7 | 241.3 | 131 |
| 0.2% Yield Strength /MPa | 462 | - | - | 275.8 | 268.9 | 248.2 | 131 | 62.1 |
| Elongation % | 53 | - | - | 59 | 63 | 64 | 59 | - |
| Coefficient of Thermal Expansion µm/m⁰C | - | 14 | 14.8 | 15.5 | 16.2 | 16.9 | 17.8 | - |
| Thermal Conductivity /kcal/(hr.m.°C) | - | 15.5 | 17.1 | 18.9 | 20.7 | 21.6 | 23.5 | - |
| Modulus of Elasticity/ x105 MPa | 2.34 | 2 | 1.93 | 1.79 | 1.72 | 1.65 | 1.52 | - |
| 1400 | 1500 | 1600 | 1700 | 1800 | Temperature, °F |
|---|---|---|---|---|---|
| 32 | 22 | 14 | 9 | 5 | 100 hours, ksi |
| 23 | 15 | 9 | 6 | 2 | 1000 hours, ksi |
Due to its strength, thermal stability, and oxidation resistance, Alloy 188 is widely used in aerospace and industrial gas turbines, as well as high-temperature chemical environments.
Its performance in thermal fatigue, cyclic oxidation, and corrosive exhaust environments makes it ideal for components with long service life and demanding safety requirements.
It is a cobalt-based alloy containing chromium, nickel, tungsten, and small amounts of lanthanum, carbon, and silicon to enhance strength, oxidation resistance, and scale adherence.
Alloy 188 retains structural integrity and oxidation resistance in environments up to 1093°C (2000°F).
Primarily in aerospace turbine engines and industrial gas turbines, especially where combustion products and high heat cycles are present.
They are the same material. “Haynes 188” is a registered trademark name by Haynes International.
NeoNickel supplies Alloy 188 plate, sheet, round bar, and welding wire.
Looking for a trusted supplier of Alloy 188? NeoNickel provides extensive stock across Europe, fast turnaround, and technical expertise for high-temperature alloy projects. Add a product to your enquiry basket or contact our specialists for tailored support.
Can't find the information you need? Please contact us directly.
Proud members of the British Valve & Actuator Association