Precious Metal B596
GB B596
ASTM B596 covers a hardened gold-copper contact alloy in which copper and an ordering heat treatment raise hardness and wear resistance above pure gold while retaining its tarnish resistance.
Reference datasheet — B596 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the H condition
B596 tempers and conditions
B596 is supplied in 4 conditions, soft to hard. H is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for forming, heading, riveting or coiling of contacts before final hardening. | 190 | 420 | 32 | 135 HV | 16 % IACS |
Half hard | Intermediate temper when both moderate spring force and some bending ductility are needed. | 450 | 600 | 10 | 166 HB | 15 % IACS |
HDefault Hardened | Default stock condition for sliding, wiping and slip-ring contacts needing wear resistance and contact force. | 620 | 760 | 3 | 215 HV | 15 % IACS |
Order-hardened | Choose for maximum hardness, wear life and the lowest resistivity, after parts are formed. | 780 | 900 | 3 | 265 HV | 25 % IACS |
What is B596?
ASTM B596 covers a hardened gold-copper contact alloy in which copper and an ordering heat treatment raise hardness and wear resistance above pure gold while retaining its tarnish resistance. Engineers select it for low-force sliding and wiping contacts that must hold a stable, oxide-free contact resistance over long cycle life; it is supplied as drawn wire, strip and stamped blanks in O, H02, H and OA conditions. Electrical conductivity is only 15% IACS, thermal conductivity 62 W/m·K and maximum service temperature about 200 °C, with 3% elongation in the default condition, so sections stay thin. Cost tracks the gold content, making hard-gold plating over a copper alloy spring the usual lower-cost substitute. B596 has a density of 15.5 g/cm³ (0.56 lb/in³), heavier than 77% of precious metal grades. It melts at 885°C (1,625 °F). B596 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 98% of precious metal grades. Elongation at break is 3% and the elastic modulus is 92 GPa (13.3 Msi).
What is B596 used for?
- slip rings
- potentiometers
- connector contacts
Advantages
- High strength — 620 MPa (89.9 ksi), better than 98% of precious metal grades
- Easy to machine — 55/100, better than 86% of precious metal grades
- Polishes to a fine finish — 95/100, better than 86% of precious metal grades
- Readily welded — 75/100, better than 78% of precious metal grades
Limitations
- Limited ductility — 3%, worse than 95% of precious metal grades
- Limited formability — 30/100, worse than 94% of precious metal grades
- Limited service temperature — 200°C (392 °F), worse than 89% of precious metal grades
- Heavy — 15.5 g/cm³ (0.56 lb/in³), worse than 77% of precious metal grades
- High embodied carbon — 12,000 kg CO₂/kg, worse than 76% of precious metal grades
B596 properties
Typical room-temperature values for B596-H; bars are the position among precious metal grades.
Physical3
B596 has a density of 15.5 g/cm³ (0.56 lb/in³), heavier than 77% of precious metal grades. It melts at 885°C (1,625 °F).
Mechanical10
B596 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 98% of precious metal grades. Elongation at break is 3% and the elastic modulus is 92 GPa (13.3 Msi).
Thermal6
B596 is rated for continuous service to 200°C (392 °F). It conducts heat at 62 W/m·K (35.8 BTU/hr·ft·°F), worse than 69% of precious metal grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
B596 conducts electricity at 15 % IACS, worse than 65% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 69% of precious metal grades.
Sustainability4
Producing a kilogram of B596 takes about 200,000 MJ of energy and emits 12,000 kg of CO₂ — more than 85% of precious metal grades. Typical recycled content is 45%.
Manufacturability8
B596's machinability is good (55/100, better than 86% of precious metal grades); weldability very good (75/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the precious metal family
Yield strength against density for every precious metal grade FabDigit runs. B596 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with B596
Is B596 easy to machine?
Turns and skives cleanly with sharp, polished-rake carbide or diamond tooling and light oil; keep all swarf for refining.
Can B596 be welded?
Resistance, percussion and laser welding to contact carriers are standard; avoid gas welding to prevent copper oxidation and gold loss.
Can B596 be formed, bent or molded?
Anneal at 600–700 °C in reducing or inert atmosphere and quench to the soft, disordered state before heavy drawing, coiling or heading; cold-work rates of 40–60 % between anneals are routine.
B596 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 |
|---|---|---|
| Augold content per specification (18 karat class) | 74.5 – 75.5 | 75 |
| Agincidental | ≤ 0.1 | — |
| Other (total impurities)total of all elements other than Au and Cu | ≤ 0.15 | — |
| Cubalance copper | balance | — |
What surface finishes work on B596?
Bright-drawn or buffed to a mirror finish; no plating needed, but hard-gold flash or Rh overlay is occasionally applied to wiping surfaces.
How much does B596 cost?
B596 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
B596 — frequently asked
What is B596 used for?
B596 is typically used for slip rings, potentiometers and connector contacts. In short: hardest gold contact alloy; tarnish-free wiping contacts; low conductivity, gold cost.
What is the yield strength of B596?
B596 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 98% of precious metal grades. Strength varies by condition: see the 4 listed tempers.
Is B596 easy to machine?
Reasonably — machinability is rated good (55/100, better than 86% of precious metal grades). Turns and skives cleanly with sharp, polished-rake carbide or diamond tooling and light oil; keep all swarf for refining.
Can B596 be welded?
Yes — weldability is rated very good (75/100). Resistance, percussion and laser welding to contact carriers are standard; avoid gas welding to prevent copper oxidation and gold loss.
What surface finishes work on B596?
Bright-drawn or buffed to a mirror finish; no plating needed, but hard-gold flash or Rh overlay is occasionally applied to wiping surfaces.
Can B596 be formed, bent or molded?
Anneal at 600–700 °C in reducing or inert atmosphere and quench to the soft, disordered state before heavy drawing, coiling or heading; cold-work rates of 40–60 % between anneals are routine.
What is the maximum service temperature of B596?
B596 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between B596-H and B596-O?
H is the default condition — default stock condition for sliding, wiping and slip-ring contacts needing wear resistance and contact force. O: pick for forming, heading, riveting or coiling of contacts before final hardening. Yield strength is 620 MPa in H versus 190 MPa in O.
How much does B596 cost?
B596 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B596 — Specification for Gold-Copper Alloy Electrical Contact Material — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (precious metals and electrical contact materials) — ASM International (1990)
- ASM Alloy Phase Diagrams — Au-Cu system — ASM International (2016)
- Precious-metal contact wire and strip alloy data (Au-Cu tempers) — Deringer-Ney / Heraeus (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.