1. What are the key features of Inconel and Incoloy 800/800H/800HT/825/925 bars?
Answer:
These nickel-based and nickel-iron-chromium alloys offer:
Excellent resistance to oxidation and carburization at high temperatures
Good corrosion resistance in reducing and mildly oxidizing environments
High mechanical strength at elevated temperatures (especially 800H and 800HT)
Good ductility and weldability
Versatility in chemical, petrochemical, and power generation applications
Different variants are tailored for specific conditions: 800H and 800HT for high-temperature strength, 825 and 925 for corrosion resistance in acidic or chloride-containing media.
2. What is the typical chemical composition of these nickel alloy bars?
Answer:
Typical compositions (weight %) are:
Incoloy 800 / 800H / 800HT: Ni: 30–35%, Fe: 39–45%, Cr: 19–23%, C: 0.05–0.10%
Incoloy 825: Ni: 38–46%, Fe: 28–34%, Cr: 19.5–23.5%, Mo: 2.5–3.5%, Cu: 1.5–3.0%
Incoloy 925: Ni: 40–44%, Fe: 25–28%, Cr: 19–21%, Mo: 2–2.5%, Cu: 1.5–2.5%, Ti: 0.4–0.7%
Inconel variants: Ni: 50–70%, Cr: 14–23%, Mo/Nb depending on grade
The differences in alloying elements give specific resistance to high temperature, corrosion, or mechanical stress.
3. What are the typical applications of Incoloy and Inconel bars?
Answer:
Applications include:
Heat exchanger tubes and furnace components
Chemical and petrochemical process equipment (acids, alkalis, chlorides)
Boiler and power generation components
Marine engineering and seawater piping
Oil and gas industry equipment, including offshore platforms
Bars can be machined or forged into shafts, fasteners, flanges, and other critical components.
4. What standards do these bars conform to?
Answer:
ASTM B407 / B444 – Nickel Alloy Bars, Sheets, and Plates
UNS designations: N08800 / N08810 (800/800H/800HT), N08825 (825), N09925 (925)
ASME SB407 – Nickel Alloy Bars
ISO 15156 for corrosion resistance in sour environments (for 825 and 925)
Compliance ensures controlled chemical composition, mechanical properties, and dimensional accuracy.
5. What are the mechanical properties of Incoloy and Inconel bars?
Answer:
Typical mechanical properties (annealed condition):
| Alloy | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| 800 | 485–690 | 275–310 | 30–40 |
| 800H | 485–620 | 275–310 | 30–35 |
| 800HT | 485–620 | 275–310 | 30–35 |
| 825 | 550–690 | 275–310 | 30–40 |
| 925 | 550–690 | 275–310 | 30–40 |
Properties vary depending on exact heat treatment and bar diameter.
