Alloy 230 (UNS N06230),High-Performance Nickel-Chromium-Tungsten Superalloy

Key Specifications:

UNS N06230 | ASTM B435 / B564 / B619 / B622 |

AMS 5878 / 5891 | Max Service Temp: 1149°C |

Density: 8.97 g/cm³ | Tensile Strength: ≥827 MPa

1. Material Overview: Engineered for Cyclic Thermal Extremes

Alloy 230 (UNS N06230) is a premium solid-solution strengthened nickel-chromium-tungsten superalloy, widely recognized for its exceptional performance in high-temperature cyclic environments. Manufactured in full compliance with ASTM B435, B564, B619, B622 and corresponding ASME SB specifications, this nickel alloy also meets stringent aerospace standards AMS 5878 and AMS 5891.

Designed to outperform conventional alloys like Alloy 600 and Alloy 556, UNS N06230 relies on a unique Ni-Cr-W-Mo-La formulation. It forms a dense, spallation-resistant protective oxide film, ensuring reliable operation in oxidizing, carburizing and nitriding atmospheres up to 1149°C. Its lower thermal expansion and superior microstructural stability make it the definitive choice for gas turbine hot sections and industrial furnace components worldwide.

2. Standard Chemical Composition (wt%): Ni-Cr-W-Mo-La Foundation

The carefully controlled chemistry of UNS N06230 guarantees long-term high-temperature strength and oxidation resistance. Trace lanthanum addition significantly improves oxide scale adhesion during severe thermal cycling.

P max 0.030, S max 0.015. Tungsten and molybdenum provide solid-solution strengthening for creep resistance; chromium ensures oxidation/sulfidation protection.

3. Heat Treatment & Mechanical Properties

3.1 Solution Annealing Process

All UNS N06230 products are delivered in the solution-annealed condition. The standard heat treatment at 1177–1246°C followed by rapid air or water quenching dissolves secondary phases, homogenizes the austenitic microstructure, and maximizes ductility and formability. Each shipment is backed by full heat treatment records and PMI spectral reports.

3.2 Room-Temperature Mechanical Properties (Annealed)

• Tensile Strength: ≥827 MPa
• Yield Strength (0.2% offset): ≥345 MPa
• Elongation: ≥40%
• Brinell Hardness: ≤240 HB

3.3 Physical & High-Temperature Characteristics

Density: 8.97 g/cm³ | Expansion Coefficient (20–1000°C): 13.1×10⁻⁶/°C. The alloy’s low thermal expansion minimizes stress and distortion in critical components. It supports continuous oxidizing service up to 1149°C with outstanding resistance to grain coarsening after prolonged exposure.

4. Core Performance Advantages of UNS N06230

4.1 Superior Cyclic Oxidation Resistance

The Cr-La protective system generates a self-stable oxide scale that resists spalling under repeated heating/cooling cycles. Cyclic oxidation life far exceeds conventional alloys in combustion and flue gas environments.

4.2 Leading Carburization & Nitriding Resistance

Alloy 230 effectively blocks carbon and nitrogen ingress, preventing embrittlement and internal oxidation. This makes it the preferred material for heat treatment fixtures, retorts, and radiant tubes in controlled atmospheres.

4.3 Exceptional Creep Strength & Thermal Stability

Thanks to W-Mo solid-solution strengthening, the alloy maintains stable mechanical properties and a fine grain structure after thousands of hours at ultra-high temperatures, resisting thermal fatigue and structural failure under combined mechanical/thermal loads.

4.4 Low Thermal Expansion & Anti-Fatigue Performance

A low linear expansion coefficient effectively reduces thermal stress in expansion joints, high-temperature ducts, and burner assemblies, greatly extending service life.

4.5 Reliable Fabrication & Weldability

In solution-annealed condition, UNS N06230 exhibits excellent hot forging, cold bending, and machining characteristics. Welding with matched ERNiCrWMo-1 filler wire via GTAW/GMAW ensures low cracking sensitivity and robust on-site joining quality.

5. UNS N06230 Product Range & Dimensions

We supply a comprehensive inventory of Alloy 230 products manufactured to ASTM/ASME standards for ultra-high-temperature systems:

• Forged Pipe Fittings: 90° elbows, tees, reducers, caps. Sizes 1/2″ – 48″, SCH10 – SCH160. Custom heavy-wall configurations available.
• Seamless Pipes & Tubes: OD 16mm – 720mm, WT 3mm – 90mm. Hot-finished and cold-drawn, custom lengths.
• Plates, Sheets & Bars: Thick plates, thin sheets, round and flat bars for forging blanks and CNC machining.
• High-Temperature Flanges: WN, SO, blind flanges and custom furnace forgings.

6. Key Application Fields

• Gas Turbine & Aerospace: Combustion liners, transition ducts, flame holders, thermocouple sheaths.
• Industrial Heat Treatment: Carburizing/nitriding furnace retorts, radiant tubes, furnace rolls, baskets.
• Petrochemical & Refining: Reformer furnace tubing, high-temperature reactors, ammonia burner components.
• Thermal Power & Waste-to-Energy: Flue gas ducts, recuperator internals, high-temperature dampers.
• Special Facilities: Vacuum furnace hot zones, thermal expansion joints, pressure vessel fittings.

7. Quality Assurance & Certified Mill Test Reports

All Alloy 230 (UNS N06230) products are manufactured under our ISO 9001 quality system. Inspection workflow includes: raw material spectral recheck → solution heat treatment → mechanical testing → UT/MT non-destructive testing → dimensional verification → laser marking & vacuum packaging. Every product is supplied with an EN 10204 3.1 mill test certificate. Standard laser marking ensures full traceability with grade, heat number, and size.

Inquire today for Alloy 230 UNS N06230 seamless tubes, forged fittings, and custom high-temperature forgings. Full mill certifications and PMI reports included.

Related resources: Browse our full range of nickel alloy pipe fittings & seamless tubes, or learn more about our manufacturing capabilities on the C&N YouTube channel for product testing and factory updates.