Precious Metal 70Ag-30Ni-O (Annealed)
Temper · default condition
ASTM B427
Default condition: maximum ductility for riveting, stamping, deep drawing and welding of contact buttons onto carriers.
Values for the O condition
Other 70Ag-30Ni tempers and conditions
70Ag-30Ni is listed in 6 conditions; see the grade overview at 70Ag-30Ni.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefaultThis page Annealed | Default condition: maximum ductility for riveting, stamping, deep drawing and welding of contact buttons onto carriers. | 110 | 260 | 25 | 58 HB | 70 % IACS |
Quarter hard | Pick when slightly stiffer strip is needed for stamping self-supporting contact blades while keeping good bendability. | 230 | 320 | 12 | 75 HB | 69 % IACS |
Half hard | Intermediate temper balancing formability and contact-force stiffness for stamped bridge contacts. | 300 | 360 | 7 | 84 HB | 68 % IACS |
Full hard | Pick for maximum hardness/wear resistance in sliding or lightly formed contact parts where bending is minimal. | 370 | 410 | 3 | 95 HB | 68 % IACS |
Spring temper | Pick for self-springing contact fingers and wiper elements that must supply their own contact force. | 420 | 450 | 2 | 108 HB | 67 % IACS |
Spring hard | Heavily cold-worked spring temper of AgNi30 contact alloy — highest strength and spring-back for contact springs and blades, at the cost of ductility. | 430 | 470 | 2 | 135 HV | 60 % IACS |
What is 70Ag-30Ni-O?
70Ag-30Ni-O is 70Ag-30Ni in the O temper — default condition: maximum ductility for riveting, stamping, deep drawing and welding of contact buttons onto carriers. 70Ag-30Ni-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 80% of precious metal grades. Elongation at break is 25% and the elastic modulus is 110 GPa (16 Msi). 70Ag-30Ni-O has a density of 9.95 g/cm³ (0.359 lb/in³), lighter than 67% of precious metal grades. It melts at 961°C (1,762 °F).
Advantages
- Stiff — 110 GPa (16 Msi), better than 76% of precious metal grades
- High electrical conductivity — 70 % IACS, better than 75% of precious metal grades
Limitations
- Low strength — 110 MPa (16 ksi), worse than 80% of precious metal grades
- Hard to polish — 70/100, worse than 76% of precious metal grades
70Ag-30Ni-O properties
Typical room-temperature values for 70Ag-30Ni-O; 17 are specific to this condition. Other listed values are 70Ag-30Ni reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
70Ag-30Ni-O has a density of 9.95 g/cm³ (0.359 lb/in³), lighter than 67% of precious metal grades. It melts at 961°C (1,762 °F).
Mechanical13
70Ag-30Ni-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 80% of precious metal grades. Elongation at break is 25% and the elastic modulus is 110 GPa (16 Msi).
Thermal5
70Ag-30Ni-O is rated for continuous service to 250°C (482 °F). It conducts heat at 300 W/m·K (173.3 BTU/hr·ft·°F), better than 74% of precious metal grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
70Ag-30Ni-O conducts electricity at 70 % IACS, better than 75% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 66% of precious metal grades.
Sustainability4
Producing a kilogram of 70Ag-30Ni-O takes about 1,100 MJ of energy and emits 80 kg of CO₂ — less than 71% of precious metal grades. Typical recycled content is 50%.
Manufacturability8
70Ag-30Ni-O's machinability is fair (45/100, better than 59% of precious metal grades); weldability very good (70/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 70Ag-30Ni-O
Is 70Ag-30Ni easy to machine?
Turns and drills but is gummy — use sharp, high-rake carbide, generous coolant and collect all chips as precious-metal scrap; the Ni phase mildly abrades tooling.
Can 70Ag-30Ni be welded?
Normally resistance- or ultrasonic-welded (or Ag-brazed) as contact buttons onto Cu/CuZn carriers; fusion welding of the bulk is not practised because the two phases are immiscible.
Can 70Ag-30Ni be formed, bent or molded?
Made by press-sinter-extrude powder metallurgy then cold rolled/drawn; soft temper rivets and deep-draws easily, intermediate anneals at 600–700 °C restore ductility after ~50 % reduction.
What surface finishes work on 70Ag-30Ni?
Used bare in most switchgear; optional Ag or hard-Au flash for shelf life and dry-circuit reliability; anti-tarnish passivation recommended for sulphur-containing environments.
70Ag-30Ni 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 |
|---|---|---|
| Agsilver matrix, fine-silver purity feedstock | 69 – 71 | 70 |
| Other (total impurities)Cu, Fe, O and residual PM binders per ASTM B427 | ≤ 0.15 | — |
| Nidispersed nickel particles, typically 1–5 µm | balance | — |
70Ag-30Ni-O — frequently asked
What is 70Ag-30Ni-O used for?
70Ag-30Ni-O is typically used for circuit breaker contacts, contactor contacts and high-current relays. In short: highest Ni content in family; best anti-weld Ag-Ni grade; cadmium-free arcing contact.
What is the yield strength of 70Ag-30Ni-O?
70Ag-30Ni-O has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 80% of precious metal grades. Strength varies by condition: see the 6 listed tempers.
Is 70Ag-30Ni-O easy to machine?
Reasonably — machinability is rated fair (45/100, better than 59% of precious metal grades). Turns and drills but is gummy — use sharp, high-rake carbide, generous coolant and collect all chips as precious-metal scrap; the Ni phase mildly abrades tooling.
Can 70Ag-30Ni-O be welded?
Yes — weldability is rated very good (70/100). Normally resistance- or ultrasonic-welded (or Ag-brazed) as contact buttons onto Cu/CuZn carriers; fusion welding of the bulk is not practised because the two phases are immiscible.
What surface finishes work on 70Ag-30Ni-O?
Used bare in most switchgear; optional Ag or hard-Au flash for shelf life and dry-circuit reliability; anti-tarnish passivation recommended for sulphur-containing environments.
Can 70Ag-30Ni-O be formed, bent or molded?
Made by press-sinter-extrude powder metallurgy then cold rolled/drawn; soft temper rivets and deep-draws easily, intermediate anneals at 600–700 °C restore ductility after ~50 % reduction.
What is the maximum service temperature of 70Ag-30Ni-O?
70Ag-30Ni-O is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 70Ag-30Ni-O and 70Ag-30Ni-H08?
O is the default condition — default condition: maximum ductility for riveting, stamping, deep drawing and welding of contact buttons onto carriers. H08: heavily cold-worked spring temper of AgNi30 contact alloy — highest strength and spring-back for contact springs and blades, at the cost of ductility. Yield strength is 110 MPa in O versus 430 MPa in H08.
Sources
- ASTM B427 — Standard Specification for Silver-Nickel Electrical Contact Material — ASTM International (2021)
- Data Book of Electrical Contacts (AgNi contact materials) — Doduco / AMI Doduco (2012)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Silver-nickel contact strip and rivet materials — Metalor Technologies / Umicore Contact Materials (2022)
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.