Haynes 230 (UNS N06230) – Nickel-Chromium-Tungsten-Molybdenum Alloy for Extreme High-Temperature Service

Exceptional High-Temperature Strength and Thermal Stability – Haynes 230 is a solid-solution strengthened material that combines excellent high-temperature strength with good fabricability at room temperature. The alloy is particularly effective for very long-term applications at temperatures of 1200°F (650°C) or more. The unique combination of tungsten (13-15%) and molybdenum (1-3%) for solid-solution strengthening, along with controlled carbon (0.05-0.15%) and chromium (20-24%) for carbide strengthening, provides outstanding high-temperature strength. The alloy demonstrates resistance to grain coarsening with prolonged exposure to high temperatures, maintaining its mechanical properties over extended service periods.

Superior Oxidation Resistance – Haynes 230 offers outstanding resistance to oxidizing environments up to 2100°F (1149°C) for prolonged exposures. The high chromium content (20-24%) forms a dense, adherent Cr₂O₃ protective oxide scale. The addition of lanthanum (0.005-0.05%) enhances oxide scale adhesion, preventing spalling during thermal cycling. This provides superior performance in cyclic thermal conditions where other alloys would fail by scale spallation.

Premier Resistance to Nitriding Environments – The alloy exhibits premier resistance to nitriding environments, making it suitable for ammonia burner catalyst grid supports and other applications where nitriding would cause rapid degradation of lesser alloys.

Excellent Long-Term Thermal Stability – Unlike many high-temperature alloys that degrade through sigma phase or other embrittling precipitates, Haynes 230 maintains its ductility and toughness through extended high-temperature exposure. This ensures reliable service life measured in years rather than months.

Lower Thermal Expansion – The alloy demonstrates lower thermal expansion characteristics than most high-temperature alloys, reducing thermal stress and fatigue in components subject to thermal cycling. This is particularly beneficial in aerospace gas turbine components and industrial furnace applications.

Excellent Fabricability and Weldability – Haynes 230 has excellent forming and welding characteristics. It may be forged or otherwise hot-worked, provided it is held at 2150°F (1177°C) for sufficient time. The alloy is also readily formed by cold-working due to its good ductility. It can be welded by a variety of techniques, including gas tungsten arc (GTAW), gas metal arc (GMAW), resistance welding, and shielded metal arc welding (SMAW).

ASME Vessel Code Coverage – Haynes 230 is covered by ASME Vessel Code case No. 2063 for Section I and Section VIII, allowing its use in pressure vessel applications under the ASME Boiler and Pressure Vessel Code.

Extended Service Life – The alloy is capable of outlasting stainless steels and nickel alloys by as much as 100 to 1 depending upon the temperature. Alternatively, the higher strength of 230 alloy allows for the use of design section thicknesses as much as 75 percent thinner than lesser alloys with no loss in load-bearing capability.