Haynes230 Alloy

Haynes230 (UNS N06230/W.Nr 2.4733) is a high – performance nickel – chromium – tungsten – molybdenum alloy that has been engineered to meet the demands of extreme high – temperature applications. It combines an array of outstanding properties, making it a preferred material in various industries.

1. Chemical Composition (Mass Fraction, %)

2. Physical Properties

• Density: 8.97 g/cm³. This relatively high density is a characteristic of nickel – based superalloys and is a factor to consider in applications where weight is a concern, although its superior performance often outweighs the density drawback.
• Melting Point: 1301 – 1371 °C. The wide melting range allows for some flexibility during casting and welding processes, but precise temperature control is still crucial to ensure the integrity of the alloy.
• Elastic Modulus: At room temperature, it is approximately 211 GPa. This indicates the alloy’s stiffness and ability to resist elastic deformation under an applied load.
• Coefficient of Thermal Expansion: In the range of room temperature to high temperatures, it has a relatively lower coefficient compared to many high – temperature alloys, around 12.42×10⁻⁶ cm/cm – °C. This property is beneficial as it reduces thermal stress during heating and cooling cycles.
• Resistivity: 126.3 μΩ·cm. This electrical property is relevant in applications where electrical conductivity or resistance to electrical current is a factor, such as in some electrical heating elements.
• Thermal Conductivity: 8.9 W/m – °C at 23 °C. While not as high as some metals, it has sufficient thermal conductivity to dissipate heat in high – temperature applications without overheating.
• Exceptional High – temperature Strength: Incorporating solution strengthening mechanisms, Haynes230 offers superior high – temperature strength. It can maintain its structural integrity and mechanical properties under extreme temperature conditions, making it suitable for applications where components are subjected to high mechanical loads at elevated temperatures.
• Outstanding Oxidation Resistance: Exhibits excellent resistance to oxidation, forming a protective oxide scale that can withstand temperatures up to 1149 °C (2100 °F) for prolonged exposures. This makes it ideal for use in oxidizing environments such as those found in industrial furnaces and gas turbines.
• Premier Nitriding Resistance: Haynes230 shows remarkable resistance to nitriding environments. Nitriding can cause degradation in many materials, but this alloy’s composition allows it to maintain its properties even in the presence of nitrogen – containing atmospheres at high temperatures.
• Excellent Long – term Thermal Stability: Not only does it perform well in the short term at high temperatures, but its long – term thermal stability is also a significant advantage. It can operate continuously at high temperatures without significant degradation in performance, ensuring reliable service over extended periods.
• Good Fabricability: Despite its high – performance nature, Haynes230 has good formability and weldability. It can be shaped through cold working processes, and intermediate annealing can be used to restore ductility. The alloy can be welded using various techniques such as gas tungsten arc (GTAW), gas metal arc (GMAW), and resistance welding.

3. Performance Characteristics

4. Production Standards

Haynes230 is produced in accordance with several industry – recognized standards. These standards ensure the quality and consistency of the alloy, making it suitable for critical applications. Some of the relevant standards include AMS 5878 and ASTM B435 (chemistry – related specifications). These standards cover aspects such as chemical composition limits, mechanical property requirements, and testing procedures.

5. Application Fields

• Aerospace:

◦ Gas Turbine Components: Used in combustion cans, transition ducts, flame holders, and thermocouple sheaths. These components are exposed to high – temperature and high – pressure gases, and Haynes230′s high – temperature strength and oxidation resistance make it an ideal choice. For example, in the combustion cans, it can withstand the intense heat of the fuel – air combustion process without significant degradation.

• Power Generation:

◦ Industrial Furnaces: Employed in furnace retorts, chains, fixtures, and burner flame shrouds. In industrial heating applications, the alloy’s ability to resist oxidation and maintain its strength at high temperatures is crucial for ensuring the efficient and long – lasting operation of the furnace.

◦ Heat Exchangers: Haynes230 is used in high – temperature heat exchangers, where it can transfer heat effectively while resisting corrosion and degradation in the hot fluid environment.

• Chemical Processing:

◦ Catalyst Grid Supports: In ammonia burners, the alloy is used to make catalyst grid supports. Its resistance to both high temperatures and chemical environments is essential for supporting the catalysts during the chemical reactions.

◦ Nitriding Furnace Internals: Due to its premier nitriding resistance, it is suitable for use in the internals of nitriding furnaces, such as trays and sparger tubes.

• Other Applications:

◦ High – temperature Bellows: These are used in applications where flexibility and high – temperature resistance are required, such as in some industrial machinery and instrumentation.

◦ Heat – treating Baskets and Grates: Haynes230 is used to make these components as it can withstand the repeated heating and cooling cycles in heat – treating processes without warping or degrading.

6. Processing Considerations

• Hot Working: The alloy can be hot worked in a specific temperature range. Heating the workpiece to the appropriate temperature is crucial, and the size and complexity of the part need to be considered. For complex shapes, pre – equilibrating at an intermediate temperature before reaching the final hot – working temperature can be beneficial. It is important to work the alloy quickly with sufficient deformation to maintain heat within the workpiece.
• Cold Working: Cold working operations like cold rolling and stamping can be carried out, but care must be taken to avoid excessive strain. Intermediate annealing may be necessary to restore ductility and balance the properties of the alloy.
• Welding: As mentioned earlier, Haynes230 has good weldability. However, appropriate filler materials and welding procedures should be selected. Extended time at intermediate age – hardening temperatures should be avoided to prevent any adverse effects on the mechanical and corrosion – resistant properties of the welded joint. After welding, post – weld heat treatment may be required to relieve stress and optimize the performance of the joint.
• Heat Treatment: Haynes230 is typically supplied in a solution – heat – treated condition. The recommended solution heat – treatment range is 2150 – 2275 °F (1177 – 1246 °C), followed by rapid cooling, such as water – quenching, to achieve optimal performance. This heat – treatment process helps in homogenizing the alloy’s microstructure and enhancing its mechanical properties.

In summary, Haynes230 is a versatile and high – performing alloy that plays a vital role in industries where high – temperature resistance, corrosion resistance, and mechanical integrity are of utmost importance. Its unique combination of properties makes it an ideal choice for applications that demand reliability and durability under extreme conditions.

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