Inconel 718 Springs

Inconel 718 Springs

Coiling Technologies, Inc. produces high-quality springs, with precision tolerances made from Inconel 718 alloy wire and bar diameters up to 2.50” (65 mm). Our team of engineers can assist you in designing your complex corrosive and low and high-temperature spring applications. Professionally crafted along with our rigid testing standards provides the springs for your toughest applications.

Coiling Technologies is ISO 9001-2015 certified and has quality standards in place to ensure that your product is produced to our and your standards.

What is Inconel 718?

Inconel 718 is an age-harden able Nickel-Chromium-Columbium (Niobium)-Molybdenum alloy with excellent corrosion resistant properties. It is a high strength alloy that is compatible in both high and low-temperature environments (-423 F – 1300 F) (253 C – 704 C). It exhibits excellent fatigue, creep, and rupture strength making it an ideal alloy for fabricating springs. It is a superior material choice to Inconel X750 at higher temperatures when material strength is a factor.

Wide Range of Operating Environments 

The alloy retains 75% of its tensile strength up to 1300 F (704 C). Inconel 718 remains ductile in cryogenic environments and is suitable for low-temperature applications like compressed liquid natural gas or CO₂ processing. It retains 85% of its ductility at temperatures down to -400 F (-240 C). 718 also performs better than Nimonic 90 at cryogenic temperatures. The material performs well in sour gas environments although there are other nickel alloys such as Inconel 625 and Inconel 725 that perform even better.

Inconel 718 Heat Treatment Specifications 

Inconel 718 is also resistant to hydrogen embrittlement and stress corrosion cracking with HRc values as high as 40 when in the solution annealed and aged condition. To meet these requirements the NACE MR1075 specifications for heat treatment are followed. The material is typically solution annealed at 1850-1900 F (1010 – 1040 C) and precipitation hardened at 1450 F (780 C) up to 8 hrs.

High Fatigue & Material Strength

To meet high fatigue and material strength, heat treatment is conducted by solution annealing at 1700 – 1800 F (925 – 980 C) followed by a rapid cool and precipitation hardening at 1325 F (720 C) for 8 hrs. and furnace cooling to 1150 F (620 C) for 18 hours.

Features & Benefits of Inconel 718 Springs

Coiling Technologies produces and delivers Inconel 718 custom springs that:

• Resists corrosion in most environments
• High strength with tensile values as high as 230 Ksi (1590 MPa)
• Easily fabricated into many spring and wire form elements
• Endures high temperatures up to 1300 F (704 C)
• Endures low temperatures down to -423 F (-272 C)

Industries and Applications

Coiling Technologies’ Inconel 718 custom manufactured, high strength corrosion resistant springs are used in a wide variety of industries, especially where high strength and resistance to high temperatures is critical.

Inconel 718 custom industrial, corrosion resistant springs are commonly used in the following applications:

• Jet aircraft engines
• Gas turbines
• Oil and gas
• Chemical industries
• Military applications
• Aircraft industry
• Marine applications
• Nuclear industry

 Coiling Tech Certifications & Experience

Coiling Technologies, Inc. is an ISO 9001-2015 certified manufacturer of high-tech, specialized springs and is committed to providing quality products. Coiling Technologies has the experience, expertise, and equipment to deliver the superior springs you want and the dedication and passion to provide the service you desire.

• Certified ISO 9001 manufacturer of custom large and small coil springs, compression springs, disc springs, extension springs, suspension springs, torsion springs, and wave springs.
• Has more than 45 years of experience providing top tier spring manufacturing services
• Utilizes cutting-edge technology and efficient manufacturing methods to shorten production times and improve product consistency
• Offers on-site product prototyping, including wire forms, powder coating, special coatings, magnetic particle inspections, shot peening, cycle testing, and heat treating.

Combining nearly 45 years of spring manufacturing experience with state-of-the-art equipment and technology, Coiling Technologies is dedicated to manufacturing the best corrosion-resistant Inconel springs for a variety of industries including oil and gas, energy and power generation, sub-sea environments, chemical processing, glass manufacturing, etc. Contact us today for an estimate on custom Inconel 718 springs! 

Inconel 718 Springs FAQs

What makes Inconel 718 a popular choice for high-temperature spring applications?

Inconel 718 is a nickel-chromium-molybdenum-niobium superalloy that retains approximately 75% of its tensile strength at temperatures up to 1,300°F (704°C) while also maintaining ductility at cryogenic temperatures down to −423°F (−253°C). This exceptionally wide effective operating range—from liquid helium temperature to the high-temperature end of aerospace and oil and gas service—combined with high fatigue resistance and excellent corrosion resistance makes Inconel 718 the most widely used nickel-base superalloy in the world. For spring applications, it provides high load capacity with minimal stress relaxation across a temperature window no steel or stainless steel spring can match.

What heat treatment does Inconel 718 require for spring applications, including sour service?

For most high-strength spring applications, Inconel 718 is solution annealed at approximately 1,750°F–1,800°F (955°C–982°C) and then double-aged at 1,325°F (718°C) for 8 hours, furnace cooled to 1,150°F (621°C), and held for an additional 8 hours before air cooling—producing maximum tensile strength and fatigue resistance. For sour gas or H₂S service applications governed by NACE MR0175/ISO 15156, a modified heat treatment protocol is required. This typically involves solution annealing at a higher temperature to dissolve precipitates fully, followed by a single-stage aging treatment optimized to limit final hardness to HRC 40 maximum—the threshold specified by NACE for nickel alloys in H₂S-containing environments to prevent hydrogen embrittlement and sulfide stress cracking. Engineers specifying Inconel 718 springs for sour service should identify the NACE compliance requirement explicitly so the correct heat treatment path is applied.

What mechanical properties does Inconel 718 achieve in the fully aged condition?

In the standard double-aged condition, Inconel 718 wire achieves tensile strengths typically in the range of 190,000–220,000 psi and yield strengths above 150,000 psi, depending on wire diameter and processing history. These values are substantially higher than the solution-annealed baseline, and represent a meaningful strength advantage over precipitation-hardened stainless steels such as 17-7 PH CH900 (220,000–240,000 psi tensile in wire, but limited to approximately 650°F continuous service) for applications requiring both high strength and elevated temperature capability.

How does Inconel 718 compare to Inconel X-750 for spring design?

Both are precipitation-hardenable nickel superalloys, but they are optimized for different performance profiles. Inconel 718 generally provides higher room-temperature tensile and yield strength and is the preferred choice for applications up to approximately 1,200°F (649°C) where maximum strength governs. Inconel X-750 demonstrates superior creep and stress relaxation resistance above approximately 1,200°F, making it the preferred specification for the most extreme sustained high-temperature applications. Inconel X-750 is also non-magnetic, which matters in electromagnetically sensitive downhole or aerospace assemblies where 718's slightly elevated magnetic response is unacceptable.

Can Inconel 718 springs be used at cryogenic temperatures, including in LOX and LNG applications?

Yes. Inconel 718 maintains ductility and toughness at cryogenic temperatures, retaining approximately 85% of its room-temperature ductility down to −400°F (−240°C). Unlike carbon and low-alloy steels, which undergo a ductile-to-brittle transition at low temperatures, Inconel 718 remains tough and serviceable at liquid nitrogen (−320°F), liquid oxygen (LOX at −297°F), and liquid natural gas (LNG at −260°F) temperatures. This makes it a qualified material for springs in rocket propulsion systems, cryogenic valve actuators, LNG processing equipment, and scientific instruments operating in cryogenic environments.

What industries rely on Inconel 718 springs?

Inconel 718 springs are used in jet aircraft engine components (combustor springs, turbine section springs, fuel system actuators), oil and gas equipment (downhole MWD/LWD instrument springs, wellhead valve springs, subsea tree actuators, sour service applications), chemical processing (reactor internals, heat exchanger components in high-temperature corrosive service), nuclear power generation (reactor internals, fuel handling systems), and military and defense programs requiring sustained mechanical performance across extreme thermal and corrosive environments.

What size range does Coiling Technologies offer for Inconel 718 springs?

Coiling Technologies manufactures Inconel 718 springs from wire and bar stock with wire diameters up to 2.50 inches (65 mm), supporting both precision instrumentation springs in fine wire diameters and large heavy-duty industrial coil springs in a single manufacturing program. Due to Inconel 718's high strength and rapid work hardening during coiling, specialized equipment and process expertise are required—capabilities Coiling Technologies has developed through extensive experience with nickel superalloy spring manufacturing.