Alloy 800H High Temperature Resistant Oxidation Resistant Welding Neck Flange with Creep-Rupture Strength

• Alloy 800: Lower carbon content (typically ≤ 0.10%, often around 0.05%), general high-temperature resistance
• Alloy 800H: Controlled higher carbon (0.05–0.10%) with specific grain size requirements; optimized for creep and rupture strength at 600–900 °C
• Alloy 800HT: Similar Ni-Cr-Fe base with tighter control and slightly higher (Al + Ti) for enhanced high-temperature performance

For forged flanges in high-temperature piping, 800H and 800HT are typically preferred over standard Alloy 800.

For forged flanges, common standards include:

• ASTM B564 / ASME SB564 – "Nickel Alloy Forgings" (includes UNS N08810 – Alloy 800H)
• Piping and fittings may reference:
  • ASTM B409 / B407 (plate and pipe)
  • ASTM B366 (wrought fittings)

• Nickel (30–35%) and Chromium (19–23%): Provide strong oxidation, carburization, and corrosion resistance in high-temperature atmospheres (reformers, heaters, petrochemical units)
• Higher Carbon in 800H: Boosts creep-rupture strength, making it ideal for flanges exposed to long-term high-temperature stress
• Aluminum + Titanium: Strengthen the matrix through precipitation hardening, maintaining mechanical properties at elevated temperatures