Inconel 600 / 625 / 718 — Nickel-Chromium Superalloys
Inconel
Inconel nickel-chromium superalloys maintain strength and oxidation resistance at temperatures where stainless steels weaken. We supply Inconel 600 and 625 in sheet and strip for gasket fabrication, spiral wound gasket components, and high-temperature sealing in aerospace, power generation, and chemical processing.
At a Glance
Temperature Range
-200 °C to +980 °C oxidation-resistance ceiling (Inconel 625); bolted-joint sealing limit ~650–700 °C; 718 collapses above 650–700 °C (gamma-prime overaging)
Thickness Range
0.1 mm to 6 mm (strip and sheet)
Available Forms
Technical Properties
Typical values across stocked grades. Specific grade data sheets available on request.
Alloy Composition
Nickel (Ni)
58.0% min (625)
Chromium (Cr)
20.0–23.0% (625)
Molybdenum (Mo)
8.0–10.0% (625)
Niobium + Tantalum (Nb+Ta)
3.15–4.15% (625)
Iron (Fe)
≤5.0% (625)
Carbon (C)
≤0.10%
Physical Characteristics
Density
8.44 g/cm³ (625)
Tensile Strength
827–1034 MPa (625 annealed, ASTM B443)
Elongation at Break
30–60% in 50 mm (625 annealed; 30% minimum per ASTM B443)
Thermal Conductivity
9.8 W/m·K at 100 °C (625)
Chemical Resistance
Resistant To
- High-temperature oxidation (to 980 °C in air, Inconel 625; for sealed joints limit to ~650–700 °C)
- Chloride-bearing environments (superior pitting resistance)
- Seawater and marine atmospheres
- Sulphuric acid (dilute to moderate)
- Phosphoric acid
- Hydrochloric acid (dilute)
- Flue gas and combustion products
Limited Resistance
- Concentrated hydrochloric acid (especially above 50 °C)
- Concentrated sulphuric acid at high temperature
- Molten salts (dependent on composition)
Not Recommended
- Sulphur-bearing reducing atmospheres above 600 °C (sulphidation attack)
- Molten metals such as aluminium and zinc, where dissolution occurs
- Fluorine gas at high temperature and pressure
Standards & Certifications
Standards Compliance
Common Applications
- Gas turbine and jet engine gaskets
- Exhaust system and afterburner seals
- Spiral wound gasket winding (high-temperature service)
- Chemical processing reactor gaskets (aggressive media at high temperature)
- Power generation boiler and superheater gaskets
- Nuclear reactor primary-water service (Inconel 690 is the modern alloy; Inconel 600 has documented PWSCC failure history in PWR primary water)
- Flue gas desulphurisation equipment gaskets
- Offshore and subsea equipment (sour service)
Not Recommended For
- High material cost — typically 5–10× the price of 316 stainless steel. Only justified for high-temperature or severe corrosion service.
- Difficult to machine due to rapid work hardening, which affects fabrication lead times
- Sulphidation attack occurs in reducing sulphur-bearing environments above 600 °C. Verify atmosphere before specifying.
- Low thermal conductivity creates high thermal gradients; consider thermal expansion in bolted joint design
- Longer procurement lead times than commodity stainless grades. Plan ahead for project requirements.
Available Grades
Inconel 625 Sheet
The primary nickel-chromium-molybdenum alloy for gasket fabrication. Combines high-temperature strength, corrosion resistance, and weldability. Our standard Inconel grade for spiral wound and flat gasket components.
Inconel 600 Sheet
Nickel-chromium alloy without molybdenum addition, used for high-temperature oxidation resistance. Suitable for furnace components, heat treatment equipment, and nuclear applications.
Inconel 718
Precipitation-hardenable superalloy with higher strength than 625. Optimised for service to ~650 °C; above this temperature, 625 is preferred. Used where both corrosion resistance and mechanical strength under load are required. Supplied on request.
Need Inconel?
We supply inconel in sheet, roll, and custom die-cut forms. Contact our team for pricing, data sheets, or technical assistance.
Disclaimer
This resource is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.