Inconel 702
Inconel 702 is a nickel-chromium-aluminum alloy (Ni-15.5%Cr-3.25%Al-0.7%Ti) with outstanding oxidation resistance at temperatures up to 2400°F (1316°C) — among the highest continuous service temperatures achievable in a nickel-base sheet alloy without coating. The high aluminum content promotes the formation of a dense, adherent alumina (Al₂O₃) oxide scale that is significantly more protective than the chromia (Cr₂O₃) scale formed by standard Ni-Cr alloys, enabling Inconel 702 to maintain structural integrity in highly oxidizing atmospheres at temperatures that would rapidly degrade 321 SS, 310 SS, or even Incoloy 800HT.
AMS 5550 covers Inconel 702 in sheet, strip, and coil forms — the primary product forms for fabricated combustion hardware, burner components, and high-temperature oxidizing-service fabrications. The alloy can be age-hardened by Al-Ti precipitation for applications requiring higher strength alongside oxidation resistance.
Product Forms & Size Range of Inconel 702
Inconel 702 sheet, strip, and coil per AMS 5550 is available in thicknesses from 0.004″ to 0.125″ and widths up to 48″, annealed. Used for formed combustion liners, burner cans, transition ducts, thermocouple protection tubes, and radiant tube end closures in industrial and aerospace high-temperature oxidizing environments.
HEAT TREATMENT OF INCONEL 702
Inconel702 is annealed at 1800–2000°F (982–1093°C) with rapid water quench for the fully soft condition suitable for forming operations. Age hardening at 1325°F (718°C) for 4 hours air cool then 1150°F (621°C) for 8 hours air cool precipitates Ni₃(Al,Ti) gamma-prime for increased strength — useful when the combination of oxidation resistance and structural strength are required simultaneously. Maximum oxidation resistance is retained in both annealed and age-hardened conditions due to the high Al content forming the protective Al₂O₃ scale.
Hastelloy N
Ni-Mo alloy (AMS 5786) with exceptional resistance to fluoride molten salts — the high-temperature corrosion alternative when oxidation is not the primary concern.
Alloy 230
Ni-Cr-W alloy (AMS 5878/5891) — outstanding high-temperature oxidation and nitriding resistance with better creep strength than Inconel 702.
Certified Material for Critical Service
Inconel 702 is supplied to AMS 5550 (sheet, strip, and coil). Mill certifications document aluminum content (3.0–4.5%), titanium content, and full heat chemistry. Mechanical properties are documented in the annealed condition. For applications requiring the age-hardened condition, the manufacturer specifies the aging cycle and verifies the resulting mechanical properties.