ASTM B564 Incoloy 825 / UNS N08825 Nickel Alloy Welding Neck Flange

Overview:

Incoloy 825 welding neck flanges are specialized components used in piping systems for various industries, especially those involving corrosive environments. Made from Incoloy 825, an alloy primarily composed of nickel, iron, and chromium, these flanges are designed to offer excellent resistance to pitting, crevice corrosion, and stress corrosion cracking.

The welding neck design features a long, tapered neck that gradually transitions into the flange body. This design allows for a more gradual stress distribution at the joint, which is beneficial in high-pressure applications. The flange is typically welded directly to the piping, ensuring a strong and reliable connection that minimizes the risk of leaks.

Incoloy 825's high nickel content provides exceptional resistance to oxidation and reduces the susceptibility to sulfide stress corrosion cracking, making these flanges suitable for use in sour gas environments and in contact with various chemicals, including sulfuric and phosphoric acids. The alloy also maintains its mechanical properties across a wide temperature range, which is particularly important in applications subject to thermal fluctuations.

Welding Incoloy 825 requires specific techniques to ensure a proper bond and to prevent issues such as cracking. Typically, TIG welding is recommended due to its precision and ability to control heat input, reducing the likelihood of altering the material's properties. Proper pre-welding and post-welding heat treatment may also be necessary to relieve any residual stresses and enhance corrosion resistance.

Applications of Incoloy 825 welding neck flanges span the oil and gas sector, power generation, wastewater treatment, and chemical processing. Their durability and resistance make them a preferred choice in environments where traditional materials would fail.

Specification:

Chemical composition:

Mechanical Properties:

Application:

1. Chemical Processing: Ideal for piping systems handling corrosive chemicals, such as acids and alkalis.

2. Oil and Gas: Used in offshore and onshore applications where harsh environments are present, particularly for sour gas service.

3. Waste Treatment: Effective in wastewater treatment plants to resist chlorides and sulfides.

4. Nuclear Applications: Suitable for components exposed to radioactive materials, ensuring safety and longevity.

5. Marine Engineering: Used in shipbuilding and marine engineering for antifouling and resistance to seawater corrosion.

6. Pharmaceuticals: In medical and pharmaceutical applications where cleanliness and corrosion resistance are critical.

7. Pulp and Paper Industry: Effective in handling bleach and other corrosive substances used in the production process.