Elgiloy Plates | UNS R30003 High-Strength, Sour-Gas & Seawater Alloy for Chemical, Oil & Gas, Marine, Pharma & Power
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A deepwater gas field off the coast had already seen too many unplanned shutdowns as 17‑7PH and Inconel X‑750 springs in subsea safety valves and choke assemblies suffered sulfide stress cracking and fatigue failures under sour gas, pressure cycling and cold seawater immersion, forcing retrieval of expensive trees and control modules years ahead of schedule. When the reliability and procurement teams re‑engineered those spring packs, flexure plates and preload components in Elgiloy Plates (UNS R30003), they moved to a cobalt‑chromium‑nickel‑molybdenum alloy whose data sheet describes it as having very high strength (spring temper tensile levels up to about 310 ksi), excellent fatigue strength and the ability to operate from cryogenic temperatures up to about 850 °F (454 °C), and which is “highly resistant to sulfide stress corrosion cracking” and “virtually immune to crevice and stress corrosion and pitting in seawater even at the highest strength levels”, turning a chronic failure point into a long‑life asset.
Elgiloy (UNS R30003), also commonly known as Phynox or Alloy 3J21, is a non‑magnetic cobalt‑chromium‑nickel‑molybdenum superalloy developed for extremely high strength, high fatigue life and outstanding corrosion resistance in both oxidising and reducing environments. Strip and plate‑type products are typically supplied to AMS 5876 and ASTM F1058/ISO 5832‑7, and producers highlight that Elgiloy strip can reach tensile strengths up to about 2600 MPa in the highest cold‑worked conditions while still maintaining useful ductility and stability across a temperature range from cryogenic to roughly 850 °F (454 °C).
For procurement heads, engineers, fabricators, OEM manufacturers and hardware or industrial supply stores serving chemical, oil & gas, marine, pharma and power‑generation markets, Elgiloy plates provide a compelling upgrade over 316L, 17‑7PH and many nickel alloys where sour gas, seawater, aggressive chemicals and high‑cycle fatigue converge. Typical published mechanical data list tensile strengths around 970 MPa and yield strengths around 480 MPa for general superalloy Elgiloy, with more detailed strip data indicating minimum tensile strengths of about 690 MPa in annealed condition and up to about 310 ksi in spring temper, alongside elastic moduli between roughly 186–221 GPa and Poisson’s ratio about 0.226. Corrosion and application notes emphasise that Elgiloy is highly resistant to sulfide stress corrosion cracking for sour well service, performs exceptionally well in harsh chemical processing atmospheres, and in seawater is described as “virtually immune to crevice and stress corrosion and pitting even at the highest strength levels”, which is a performance envelope far beyond many stainless steels and PH alloys used today.
High-quality Elgiloy Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Elgiloy Plates supplier, stockist, exporter in India to abroad |
|---|---|
| Alloy Description | Non‑magnetic cobalt‑chromium‑nickel‑molybdenum superalloy with very high strength, excellent fatigue life and outstanding resistance to sulfide stress cracking and seawater corrosion |
| UNS Designation | UNS R30003, also known commercially as Elgiloy, Phynox, Conichrome or Alloy 3J21 in various markets |
| Main Strip/Plate Standards | AMS 5876 (strip and foil), ASTM F1058 (surgical implant alloy), NACE MR0175 / MR0103 (sour service), ISO 5832‑7 (surgical implants) |
| Temperature Range | Service from cryogenic temperatures up to about 850 °F (454 °C) in many applications |
| Price | INR 20,000 – 40,000 per kg. Indicative USD 235 – 471 per kg; quoted against grade, form, size and quantity. |
UNS & Equivalent Grades
| Property | Value |
|---|---|
| UNS number | R30003 |
| Werkstoff / EN number | 2.4711 |
| EN designation | — |
| Density | 8.30 g/cm3 |
| Modulus of elasticity (20°C) | 190 GPa |
| Modulus of rigidity (20°C) | 77.2 GPa |
| Coefficient of expansion (20-300°C) | 15.2 µm/m·°C |
| Electrical resistivity (20°C) | 99.6 µΩ·cm |
| Thermal conductivity (20°C) | 12.5 W/m·K |
| Plate, sheet and strip specification | ASTM F1058 / AMS 5876 |
Identifiers and physical constants for Elgiloy. A dash means no such designation is published for this grade.
Stock & Product Availability
As an Elgiloy Plates stockist, Aurico Alloys LLP can work with strip and plate producers to supply thicknesses suitable for precision‑machined plates, spring plates, flexure elements, clamps, sealing rings and small structural components used across chemical processing, oil & gas, marine, pharma and power‑generation equipment, within the strip and sheet thickness ranges listed for AMS 5876 and related specifications. Typical strip/plate product information shows Elgiloy strip available in gauges from thin foil up to several millimetres, supplied cold reduced and optionally aged to achieve tensile strengths from about 690 MPa in annealed condition to as high as about 310 ksi in spring temper, giving designers flexibility to tune plate hardness and ductility to application needs.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Carbon (C) | — | 0.15 |
| Manganese (Mn) | 1.5 | 2.5 |
| Silicon (Si) | — | 1.20 |
| Phosphorus (P) | — | 0.015 |
| Sulfur (S) | — | 0.015 |
| Chromium (Cr) | 19.0 | 21.0 |
| Nickel (Ni) | 14.0 | 16.0 |
| Cobalt (Co) | 39.0 | 41.0 |
| Molybdenum (Mo) | 6.0 | 8.0 |
| Beryllium (Be) | — | 0.001 |
| Iron (Fe) | — | Balance |
Composition limits for Elgiloy. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical & Physical Properties
| Property (Typical, Strip/Plate) | Value – Elgiloy (UNS R30003) |
|---|---|
| Tensile Strength – general data | ≈970 MPa typical (≈141 000 psi) in some superalloy Elgiloy product forms |
| Tensile Strength – strip conditions | ≥690 MPa in annealed condition and up to about 310 ksi (≈2138 MPa) in spring temper, with some sources citing maximum strengths up to ≈2600 MPa for heavily cold‑worked strip |
| 0.2% Yield Strength | ≈480 MPa typical in general data; higher in fully cold‑worked and aged spring tempers |
| Elongation | ≈5–15% depending on product and temper, with higher elongation in annealed strip and lower in high‑strength spring tempers |
| Elastic Modulus (E) | ≈186–200 GPa in cold‑reduced strip and ≈206–221 GPa in cold‑reduced and aged conditions; general data list ≈189.6 GPa |
| Modulus of Rigidity (G) | ≈76–77 GPa (≈11.0–11.2 × 10³ ksi) |
| Hardness | ≈35–40 HRC typical for high‑strength Elgiloy, with Rockwell C values up to about 45 in some rod products |
| Service Temperature Range | From cryogenic temperatures up to about 850 °F (454 °C) in many spring and plate applications |
| Corrosion & SSC Resistance | Described as highly resistant to sulfide stress corrosion cracking and virtually immune to crevice and stress corrosion and pitting in seawater even at highest strength levels. |
Applications & Benefits
- Chemical & Oil & Gas: Elgiloy plates and strip are widely used for springs, seal elements, diaphragms, preload plates and downhole components in sour wells and aggressive chemical services thanks to their high strength, fatigue life and resistance to sulfide stress cracking and hydrogen embrittlement.
- Marine & Desalination: In marine and subsea equipment, Elgiloy’s virtual immunity to seawater crevice and stress corrosion and pitting even at the highest strength levels makes it ideal for critical springs, clamps, fasteners and sensing components in long‑life offshore installations.
- Pharma, Power & High‑Cycle Machinery: Pharma, power and high‑cycle machinery OEMs use Elgiloy for precision springs, flexures, bellows and plates in valves, compressors, control instruments and medical or implant devices as permitted by ASTM F1058 and ISO 5832‑7, where high fatigue life and corrosion resistance are mandatory.
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Conclusion
Elgiloy Plates from Aurico Alloys LLP, supplied to UNS R30003 chemistry limits and key standards such as AMS 5876, ASTM F1058, NACE MR0175 / ISO 15156‑3 and ISO 5832‑7, provide chemical, oil & gas, marine, pharma and power‑generation users with a cobalt‑based alloy that combines very high strength, outstanding fatigue life and near‑immunity to sulfide stress cracking and seawater pitting in their most critical springs, clamps and precision plate components are your highest‑risk sour‑gas, seawater and high‑cycle assets still relying on lower‑alloy stainless and nickel grades instead of optimised Elgiloy plates?