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中文 (中国) 
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Chenzhou, Hunan, China(423000）)
- 2025-9-29
- handaseal
- Read: 62
Elgiloy® is a cobalt-chromium-nickel-molybdenum alloy engineered for very high strength, excellent corrosion resistance (including sulfide stress corrosion cracking resistance) and outstanding fatigue life. It is widely used in spring-energized seals and precision springs for sour oil & gas, subsea, chemical processing, aerospace and medical applications.
Contents
Introduction & quick summary
Elgiloy® (UNS R30003) is a non-magnetic, age-hardenable cobalt-based alloy that balances high tensile strength with notable corrosion and sulfide stress corrosion cracking (SSC) resistance. Suppliers commonly provide Elgiloy as precision spring wire and strip intended for long-life energizers (canted coil, helical, cantilever, garter, full-contact) where fatigue life, low relaxation and corrosion performance are paramount. Always obtain the supplier’s mill certificate and diameter-by-temper mechanical tables for design.
Need Elgiloy energizers or samples? Request a quote — include operating fluid, temperature and gland geometry.
Core characteristics
Typical chemical composition
Typical composition ranges (use mill certificate for exact lot values):
| Element | Typical composition (wt.%) |
|---|---|
| Cobalt (Co) | ≈ 39–41% |
| Chromium (Cr) | ≈ 19–21% |
| Nickel (Ni) | ≈ 14–16% |
| Molybdenum (Mo) | ≈ 6–8% |
| Manganese (Mn) | ≈ 1.5–2.5% |
| Iron (Fe) | Balance (varies by vendor) |
| C, Si, P, S, Be (trace) | Controlled to low levels — check mill certificate |
Typical composition references: Carpenter, Elgiloy and major suppliers’ datasheets.
Key physical data
Typical physical & thermal properties (confirm with supplier datasheet for chosen temper/lot):
| Technical specification | Elgiloy® (typical) |
|---|---|
| Density | ≈ 0.308 lb/in³ (≈ 8.52 g/cm³). |
| Modulus of Elasticity (E) | ≈ 28–32 × 10⁶ psi (≈ 193–221 GPa) typical range (varies with temper). |
| Modulus of Rigidity (G) | ≈ 11.0–12.5 × 10⁶ psi (≈ 75–86 GPa) (typical). |
| Coefficient of Thermal Expansion | ≈ 7.5–8.5 µin/in-°F (70–600 °F) (~13–15 µm/m-°C). |
| Electrical Resistivity | ≈ 35–45 µΩ·in (vendor dependent). |
| Thermal Conductivity | Moderate — consult supplier datasheet for temper-specific values. |
| Max recommended continuous service temp | Guidance commonly up to ≈ 450 °C (≈ 840 °F) for many tempers; check supplier for temper-specific limits. |
Physical / thermal values referenced to major supplier datasheets.
Metallurgical behaviour & tempering
Elgiloy attains high strength through cold work and controlled ageing. Mechanical properties (UTS, YS, hardness and relaxation) depend strongly on percent cold reduction and ageing schedule. For springs, design from the supplier’s diameter-by-temper tables and the mill certificate.
Typical applications
Oil & gas (sour service)
Elgiloy is commonly specified for downhole packers, connector springs and sealing energizers in H₂S environments due to its strong SSC resistance and fatigue life. For the most severe sour environments designers may compare Elgiloy with MP35N.
Subsea & marine
Used in subsea connectors, rotary seals and cyclicly loaded components where chloride exposure and corrosion fatigue are concerns.
Chemical processing, aerospace & medical
Employed where corrosion resistance, low relaxation and long fatigue life are needed — including specialty chemical equipment, aerospace instrumentation and selected medical springs (verify biocompatibility and certification with supplier).
Forming into springs & spring types
Reminder: spring energizers are formed from wire (round or profiled) or strip. Elgiloy is commonly available in spring wire and strip and used to make a range of energizer geometries. Always confirm diameter & temper availability with your spring vendor and request diameter-by-temper mechanical tables.
- Canted Coil Springs — multi-contact ring energizers for static & dynamic seals.
- Helical Springs — compression/extension for preload and dynamic use.
- Cantilever V Springs / Cantilever U Springs — thin profile energizers for lip seals.
- Full Contact Springs — continuous contact energizers for large area seals.
- Garter / Oil & Gas Springs — ring springs for rotary seals and packers.
Forming best practices
- Polished tooling and smooth coiling to minimise surface defects.
- Conservative bend radii (recommend ≥ 3× wire diameter) to reduce crack initiation.
- Age per supplier guidance when required to reach target mechanicals.
- Qualify end joins (mechanical / laser / micro-weld) for fatigue and corrosion performance.
Alternatives & comparison
Quick comparison of common energizer materials (corrosion resistance vs typical tensile strength):
| Material | Corrosion resistance (summary) | Strength (typical UTS, ksi) |
|---|---|---|
| Elgiloy® (UNS R30003) | Excellent SSC, crevice & pitting resistance; widely used in sour service and seawater. | ~220–280 ksi (depending on temper). |
| MP35N (UNS R30035) | Excellent SSC & chloride resistance; often preferred for highest strength requirements. | ~260–300 ksi (top tempers). |
| Inconel 625 / 718 | Good general corrosion and elevated-temperature strength; SCC behaviour depends on environment. | ~120–200+ ksi (varies with alloy & temper). |
| 17-7 PH / 316L | Moderate general corrosion resistance; not preferred for severe SSC / H₂S at high loads. | ~70–180 ksi (depending on grade/temper). |
Ranges are indicative — verify exact UTS values and corrosion performance with supplier diameter-by-temper tables and mill certificates.
Selection guidance
Step 1 — Rank failure modes and constraints
- Presence of H₂S / Sulfide Stress Cracking (SSC) risk
- Corrosion type: pitting / crevice / uniform / sulfide
- Cyclic loading and required fatigue life (high-cycle vs low-cycle)
- Operating temperature and relaxation/creep requirements
- Geometry constraints (wire diameter availability) and required certifications
Step 2 — Quick decision rules
- Elgiloy®: prefer when SSC resistance, high fatigue life and good forming for multi-contact energizers are the priorities.
- MP35N: prefer for the most severe sour/chloride conditions where the very highest strength and SSC resistance are needed.
- Inconel 625 / 718: choose when elevated-temperature strength or weldability is prioritized.
- 17-7 PH / 316L: choose for less aggressive environments where cost and manufacturability are primary factors.
Always verify final selection with mill certificates, supplier diameter-by-temper mechanical tables and representative performance tests (force-deflection, high-cycle fatigue, stress-relaxation and relevant corrosion tests).
FAQ
Q1: Can Elgiloy be used to manufacture canted coil and garter springs?
A1: Yes — Elgiloy spring wire and strip are used to manufacture canted coil, helical, cantilever (V/U), garter and full-contact springs. Confirm diameter & temper availability with your wire/spring supplier.
Q2: Is Elgiloy resistant to sulfide stress corrosion cracking (SSC)?
A2: Yes — Elgiloy demonstrates strong SSC resistance and is commonly selected for sour-service energizers; however NACE/client qualification testing is typically required for critical downhole or safety-critical components.
Q3: What finishing improves Elgiloy spring performance?
A3: Electropolishing, removing tooling marks and controlling surface finish (Ra) substantially improve corrosion-fatigue life and reduce friction when paired with polymer jackets (PTFE/FFKM).
Q4: What supplier data should designers request?
A4: Request the mill certificate (UNS R30003), diameter-by-temper UTS/YS/hardness tables, stress-relaxation data at operating temperature, and representative corrosion test data for the intended fluid and environment.
References
- Elgiloy Specialty Metals — Elgiloy® wire product page and datasheets.
- Elgiloy Specialty Metals — Elgiloy® strip product page and datasheets.
- HandaSeal — Elgiloy material page (source used to align copy).
- AZoM — material overviews (supplementary).
- Coiling Technologies — Elgiloy springs manufacturing notes (supplementary).