Materials
Nickel Alloys: Inconel (600, 601, 625, 725, X750, 718)
Inconel 600
Composition: ~72% Ni, 14–17% Cr, 6–10% Fe.
Properties for Fasteners:
Excellent oxidation and corrosion resistance, especially to chloride-ion stress corrosion cracking.
Retains strength at elevated temperatures (up to ~2000°F / 1093°C).
Good mechanical properties across a wide temperature range.
Applications: Fasteners for furnace hardware, chemical processing equipment, and nuclear reactors where oxidation and stress corrosion resistance are critical.
Inconel 601
Composition: Similar to 600 but with more chromium and aluminum additions for oxide scale protection.
Properties for Fasteners:
Superior oxidation resistance at sustained high temperatures.
Forms a tough, adherent oxide scale that protects in thermal cycling environments.
High resistance to carburization and sulfurization.
Applications: Fasteners in industrial furnaces, petrochemical processing, thermal oxidizers, and gas turbine components.
Inconel 625
Composition: Ni-Cr-Mo alloy with niobium additions.
Properties for Fasteners:
Excellent corrosion resistance in seawater, acids, and harsh chemical environments.
Outstanding fatigue and creep resistance.
Maintains strength up to ~1800°F (982°C).
Applications: Marine and subsea bolting, chemical processing fasteners, aerospace ducting, and nuclear reactor hardware.
Inconel 725
Composition: Ni-Cr-Mo-Nb alloy derived from Inconel 625, strengthened through precipitation hardening.
Properties for Fasteners:
Combines the exceptional corrosion resistance of 625 with significantly higher strength.
Excellent resistance to seawater, sour gas (H₂S), carbon dioxide (CO₂), and chloride-containing environments.
High resistance to stress corrosion cracking and sulfide stress cracking.
Maintains mechanical strength in demanding subsea and downhole service conditions.
Applications: Subsea bolting, offshore oil and gas equipment, downhole completion tools, wellhead components, and other high-strength corrosion-resistant fasteners used in harsh energy environments.
Inconel X-750
Composition: Ni-Cr alloy with titanium and aluminum for age-hardening.
Properties for Fasteners:
Precipitation-hardened, offering high strength up to ~1500°F (815°C).
Excellent oxidation and creep resistance.
Commonly used for springs and bolting that require stress relaxation resistance at elevated temperatures.
Applications: Gas turbine engine components, jet engines, nuclear power fasteners, and springs in high-temperature service.
Inconel 718
Composition: Ni-Fe-Cr alloy strengthened by niobium, molybdenum, titanium, and aluminum.
Properties for Fasteners:
Precipitation-hardened alloy with extremely high strength.
Retains mechanical properties up to ~1300°F (704°C).
Excellent resistance to post-weld cracking and good fabricability compared to other Inconels.
Applications: Critical aerospace fasteners, gas turbine bolts, rocket engines, subsea bolting, and nuclear power components.
Key Takeaways for Engineered Fasteners
600 & 601 → Best for oxidation resistance at very high temperatures (furnaces, oxidizers, turbines).
625 → Excels in marine, chemical, and general subsea corrosion environments.
725 → Ideal for high-strength subsea, offshore, and downhole fasteners where both corrosion resistance and mechanical performance are critical.
X-750 → Go-to for high-strength, high-temperature springs and bolts.
718 → The most widely used Inconel fastener alloy, balancing strength, toughness, and fabricability for aerospace and subsea applications.
Materials
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The manufacturing processes, testing capabilities, and quality systems featured throughout WN Global support the production of critical components and engineered fastening solutions across demanding industries. Connect with our team to learn how our manufacturing capabilities can support your project requirements.
