Cobalt-Chrome Alloy Elgiloy-ANN (Annealed)
Heat-treated state
UNS R30003
Softest, most ductile condition — choose for deep drawing, tube forming and further cold reduction.
Values for the ANN condition
Other Elgiloy tempers and conditions
Elgiloy is listed in 5 conditions; see the grade overview at Elgiloy.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Softest, most ductile condition — choose for deep drawing, tube forming and further cold reduction. | 480 | 1,000 | 55 | 22 HRC | — |
Cold worked ~30–40 % | Intermediate strength with residual ductility — for parts that still need bending or coiling before final ageing. | 1,250 | 1,500 | 12 | 45 HRC | 1.7 % IACS |
Cold worked | Standard as-supplied wire/strip temper: coil or form the part in this state, then age-harden. | 1,700 | 1,950 | 5 | 52 HRC | — |
CWADefault Cold worked and aged | Final service condition for springs and fatigue-critical parts: maximum elastic limit, best fatigue and relaxation resistance. | 2,000 | 2,200 | 3 | 58 HRC | — |
Heavily cold worked and aged | Ultra-high-strength fine wire for hairsprings, guidewires and micro-springs where maximum tensile is needed. | 2,450 | 2,700 | 1.5 | 62 HRC | — |
What is Elgiloy-ANN?
Elgiloy-ANN is Elgiloy heat treated to ANN — softest, most ductile condition — choose for deep drawing, tube forming and further cold reduction. Elgiloy-ANN has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 1,000 MPa (145 ksi) — weaker than 77% of cobalt-chrome alloy grades. Elongation at break is 55% and the elastic modulus is 190 GPa (27.6 Msi). Elgiloy-ANN has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of cobalt-chrome alloy grades. It melts at 1,400°C (2,552 °F). CWA is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- Forms and bends easily — 70/100, better than 104% of cobalt-chrome alloy grades
- Ductile — tolerates forming and impact — 55%, better than 96% of cobalt-chrome alloy grades
- Easy to machine — 20/100, better than 96% of cobalt-chrome alloy grades
- Good corrosion resistance — 88/100, better than 88% of cobalt-chrome alloy grades
- Readily welded — 55/100, better than 80% of cobalt-chrome alloy grades
Limitations
- Low stiffness — 190 GPa (27.6 Msi), worse than 100% of cobalt-chrome alloy grades
- Limited service temperature — 500°C (932 °F), worse than 87% of cobalt-chrome alloy grades
- Low strength — 480 MPa (69.6 ksi), worse than 77% of cobalt-chrome alloy grades
Elgiloy-ANN properties
Typical room-temperature values for Elgiloy-ANN; 17 are specific to this condition. Other listed values are Elgiloy reference data and may not represent this condition. Bars are the position among cobalt-chrome alloy grades.
Physical3
Elgiloy-ANN has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of cobalt-chrome alloy grades. It melts at 1,400°C (2,552 °F).
Mechanical12
Elgiloy-ANN has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 1,000 MPa (145 ksi) — weaker than 77% of cobalt-chrome alloy grades. Elongation at break is 55% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
Elgiloy-ANN is rated for continuous service to 500°C (932 °F). It conducts heat at 12.5 W/m·K (7.22 BTU/hr·ft·°F), worse than 77% of cobalt-chrome alloy grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
Elgiloy-ANN conducts electricity at 1.7 % IACS, worse than 92% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 88% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of Elgiloy-ANN takes about 165 MJ of energy and emits 13 kg of CO₂ — more than 57% of cobalt-chrome alloy grades. Typical recycled content is 20%.
Manufacturability8
Elgiloy-ANN's machinability is poor (20/100, better than 96% of cobalt-chrome alloy grades); weldability good (55/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Elgiloy-ANN
Is Elgiloy easy to machine?
Very difficult — work-hardens rapidly; use rigid setups, positive-rake carbide or ceramic tooling, low speed, heavy feed and flood coolant, and machine in the annealed condition where possible.
Can Elgiloy be welded?
Resistance, laser and micro-TIG welding are used on thin sections, but any fusion or brazing heat recrystallises the cold work and locally destroys spring properties; re-age or design joints outside the stressed zone.
Can Elgiloy be formed, bent or molded?
Coil, bend and stamp in the annealed or cold-worked (unaged) condition with generous radii and high tool forces; springback is large, then set the shape by ageing 3–5 h at 510–540 °C.
What surface finishes work on Elgiloy?
Passivate or electropolish for medical/marine service; takes a bright mirror polish, and PTFE/parylene coatings adhere well — no anodizing.
Elgiloy chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Co | 39 – 41 | 40 |
| Cr | 19 – 21 | 20 |
| Ni | 14 – 16 | 15 |
| Mo | 6 – 8 | 7 |
| Mn | 1.5 – 2.5 | 2 |
| C | ≤ 0.15 | 0.1 |
| Besmall Be addition distinguishes Elgiloy from Be-free Phynox variants | ≤ 0.1 | 0.05 |
| Febalance, typically ~15–16 % | balance | — |
Elgiloy-ANN — frequently asked
What is Elgiloy-ANN used for?
Elgiloy-ANN is typically used for pacemaker leads, surgical springs, orthodontic wire and precision springs. In short: highest-fatigue cobalt spring alloy; corrosion-resistant spring wire; age-hardens after cold work.
What is the yield strength of Elgiloy-ANN?
Elgiloy-ANN has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 1,000 MPa (145 ksi) — weaker than 77% of cobalt-chrome alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Elgiloy-ANN easy to machine?
Not especially — machinability is rated poor (20/100, better than 96% of cobalt-chrome alloy grades). Very difficult — work-hardens rapidly; use rigid setups, positive-rake carbide or ceramic tooling, low speed, heavy feed and flood coolant, and machine in the annealed condition where possible.
Can Elgiloy-ANN be welded?
Yes — weldability is rated good (55/100). Resistance, laser and micro-TIG welding are used on thin sections, but any fusion or brazing heat recrystallises the cold work and locally destroys spring properties; re-age or design joints outside the stressed zone.
What surface finishes work on Elgiloy-ANN?
Passivate or electropolish for medical/marine service; takes a bright mirror polish, and PTFE/parylene coatings adhere well — no anodizing.
Can Elgiloy-ANN be formed, bent or molded?
Coil, bend and stamp in the annealed or cold-worked (unaged) condition with generous radii and high tool forces; springback is large, then set the shape by ageing 3–5 h at 510–540 °C.
What is the maximum service temperature of Elgiloy-ANN?
Elgiloy-ANN is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Elgiloy-CWA and Elgiloy-ANN?
CWA is the default condition — final service condition for springs and fatigue-critical parts: maximum elastic limit, best fatigue and relaxation resistance. ANN: softest, most ductile condition — choose for deep drawing, tube forming and further cold reduction. Yield strength is 2,000 MPa in CWA versus 480 MPa in ANN.
Sources
- ASTM F1058 — Wrought 40Co-20Cr-16Fe-15Ni-7Mo Alloy Wire and Strip for Surgical Implants (Grade 1, UNS R30003) — ASTM International (2022)
- Elgiloy Alloy (R30003) technical data — Elgiloy Specialty Metals (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Cobalt alloys) — ASM International (1990)
- GB/T 15005 / YB 3J21 (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.