Alloy 800 (commonly referred to as Incoloy 800) is not a typical carbon-steel alloy but rather a nickel-iron-chromium high-temperature alloy. When used for forged flanges, the chemical composition remains consistent with other product forms, with tight controls to meet standards such as ASTM B564 for forgings and related material specifications including UNS N08800.
| Element | Composition Range |
|---|---|
| Nickel (Ni) | 30.0 – 35.0% |
| Chromium (Cr) | 19.0 – 23.0% |
| Iron (Fe) | Balance (approx. 39 – 46%) |
| Carbon (C) | ≤ 0.10% |
| Manganese (Mn) | ≤ 1.50% |
| Silicon (Si) | ≤ 1.00% |
| Copper (Cu) | ≤ 0.75% |
| Sulfur (S) | ≤ 0.015% |
| Aluminum (Al) | 0.15 – 0.60% |
| Titanium (Ti) | 0.15 – 0.60% |
| Aluminum + Titanium (Al + Ti) | 0.30 – 1.20% |
When specifying Alloy 800 forged flanges, reference the following standards:
For critical applications, always verify the exact chemical composition from the mill test certificate (MTC) and ensure alignment with relevant ASTM/ASME specifications for UNS N08800. Minor variations can significantly impact high-temperature performance.