Precious Metal AuNi5-SR (Stress relieved)
Heat-treated state
Low-temperature stabilising anneal of hard strip/wire to lock in spring properties and avoid time-dependent relaxation in formed contact springs.
Values for the SR condition
Other AuNi5 tempers and conditions
AuNi5 is listed in 5 conditions; see the grade overview at AuNi5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for deep-drawn or riveted contacts, cladding/bonding stock and applications needing maximum ductility. | 160 | 400 | 28 | 105 HB | 14 % IACS |
Half hard | Balanced temper for stamped contact springs and blanked rivets that still need some bend ductility. | 440 | 560 | 9 | 152 HB | 12.5 % IACS |
HDefault Hardened | Standard stocked condition for contact wire, rivet wire and sliding/low-level relay contacts needing wear resistance. | 610 | 700 | 3 | 200 HV | 13 % IACS |
SRThis page Stress relieved | Low-temperature stabilising anneal of hard strip/wire to lock in spring properties and avoid time-dependent relaxation in formed contact springs. | 650 | 720 | 3 | 199 HB | 13.5 % IACS |
Spring hard | Choose for thin contact springs and fine wire where maximum elastic limit and wear resistance are required. | 730 | 800 | 2 | 20 HRC | 12.4 % IACS |
What is AuNi5-SR?
AuNi5-SR is AuNi5 heat treated to SR — low-temperature stabilising anneal of hard strip/wire to lock in spring properties and avoid time-dependent relaxation in formed contact springs. AuNi5-SR has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 99% of precious metal grades. Elongation at break is 3% and the elastic modulus is 105 GPa (15.2 Msi). AuNi5-SR has a density of 18.3 g/cm³ (0.661 lb/in³), heavier than 89% of precious metal grades. It melts at 990°C (1,814 °F). H is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 99% of precious metal grades
- Good corrosion resistance — 94/100, better than 79% of precious metal grades
Limitations
- Limited ductility — 3%, worse than 95% of precious metal grades
- Limited formability — 25/100, worse than 95% of precious metal grades
- High embodied carbon — 15,000 kg CO₂/kg, worse than 94% of precious metal grades
- Heavy — 18.3 g/cm³ (0.661 lb/in³), worse than 89% of precious metal grades
- Limited service temperature — 230°C (446 °F), worse than 77% of precious metal grades
AuNi5-SR properties
Typical room-temperature values for AuNi5-SR; 21 are specific to this condition. Other listed values are AuNi5 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
AuNi5-SR has a density of 18.3 g/cm³ (0.661 lb/in³), heavier than 89% of precious metal grades. It melts at 990°C (1,814 °F).
Mechanical10
AuNi5-SR has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 99% of precious metal grades. Elongation at break is 3% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
AuNi5-SR is rated for continuous service to 230°C (446 °F). It conducts heat at 61 W/m·K (35.2 BTU/hr·ft·°F), worse than 70% of precious metal grades. Thermal expansion is 14.3 µm/m·K (7.94 µin/in·°F).
Electrical3
AuNi5-SR conducts electricity at 13.5 % IACS, worse than 71% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (94/100), better than 79% of precious metal grades.
Sustainability4
Producing a kilogram of AuNi5-SR takes about 185,000 MJ of energy and emits 15,000 kg of CO₂ — more than 79% of precious metal grades. Typical recycled content is 40%.
Manufacturability7
AuNi5-SR's machinability is fair (42/100, worse than 53% of precious metal grades); weldability good (60/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AuNi5-SR
Is AuNi5 easy to machine?
Machines like soft gold — gummy, long chips; use sharp polished carbide, high speed, light feed and full swarf recovery for refining.
Can AuNi5 be welded?
Resistance, percussion and laser welding of contacts to carrier springs is standard practice; conventional fusion welding is not used.
Can AuNi5 be formed, bent or molded?
Excellent cold formability in the annealed temper (drawing, stamping, rivet heading); interanneal around 700–800 °C in reducing or inert atmosphere between heavy reductions.
What surface finishes work on AuNi5?
Takes a high mirror polish; normally used bare, or as clad/inlay strip on Cu-alloy carriers — no plating needed, degrease only with solvent to keep contact resistance low.
AuNi5 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 |
|---|---|---|
| Nisolid-solution hardener | 4.5 – 5.5 | 5 |
| Other (each)Cu, Ag, Fe, Pd trace impurities | ≤ 0.05 | — |
| Others (total) | ≤ 0.1 | — |
| Aubalance, fine gold | ≥ 94.4 (balance) | — |
AuNi5-SR — frequently asked
What is AuNi5-SR used for?
AuNi5-SR is typically used for telecom relays, reed switch contacts, instrumentation connectors and low-current relay contacts. In short: hardest low-current gold contact; minimal contact resistance; low conductivity, high cost.
What is the yield strength of AuNi5-SR?
AuNi5-SR has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 99% of precious metal grades. Strength varies by condition: see the 5 listed tempers.
Is AuNi5-SR easy to machine?
Not especially — machinability is rated fair (42/100, worse than 53% of precious metal grades). Machines like soft gold — gummy, long chips; use sharp polished carbide, high speed, light feed and full swarf recovery for refining.
Can AuNi5-SR be welded?
Yes — weldability is rated good (60/100). Resistance, percussion and laser welding of contacts to carrier springs is standard practice; conventional fusion welding is not used.
What surface finishes work on AuNi5-SR?
Takes a high mirror polish; normally used bare, or as clad/inlay strip on Cu-alloy carriers — no plating needed, degrease only with solvent to keep contact resistance low.
Can AuNi5-SR be formed, bent or molded?
Excellent cold formability in the annealed temper (drawing, stamping, rivet heading); interanneal around 700–800 °C in reducing or inert atmosphere between heavy reductions.
What is the maximum service temperature of AuNi5-SR?
AuNi5-SR is rated for continuous use to about 230°C (446 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AuNi5-H and AuNi5-O?
H is the default condition — standard stocked condition for contact wire, rivet wire and sliding/low-level relay contacts needing wear resistance. O: pick for deep-drawn or riveted contacts, cladding/bonding stock and applications needing maximum ductility. Yield strength is 610 MPa in H versus 160 MPa in O.
Sources
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (precious metal contact alloys) — ASM International (1990)
- ASM Alloy Phase Diagrams — Au-Ni system — ASM International (2016)
- Electrical contact materials data book (gold-based contact alloys) — Doduco / Deringer-Ney class data (2012)
- Electrical Contacts: Principles and Applications — CRC Press (2014)
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.