Precious Metal Pt95Co5-AC (Spheroidize annealed)
Heat-treated state · default condition
Pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation.
Values for the AC condition
Other Pt95Co5 tempers and conditions
Pt95Co5 is listed in 5 conditions; see the grade overview at Pt95Co5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose the annealed soft state before or after cold working sheet, wire and tube; 32% elongation suits hand forging, drawing and bezel setting, at only 190 MPa yield. | 190 | 430 | 32 | 124 HB | 7 % IACS |
ACDefaultThis page Spheroidize annealed | Pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation. | 250 | 480 | 20 | 128 HB | 7 % IACS |
Quarter hard | Use lightly cold-worked (about 15%) sheet or wire for ring shanks and light structural parts that must balance formability against resistance to deformation. | 400 | 550 | 15 | 152 HB | 6.8 % IACS |
Half hard | Pick half-hard stock cold worked about 30–35% for prongs, clasps and chain parts needing rigidity; 520 MPa yield comes with elongation reduced to 8%. | 520 | 640 | 8 | 10 HRC | 6.8 % IACS |
Full hard | Choose heavily cold-worked wire or strip (50%+ reduction) for spring clasps and earring posts where hardness and springiness are highest; elongation drops to 3%. | 620 | 720 | 3 | 18 HRC | 6.7 % IACS |
What is Pt95Co5-AC?
Pt95Co5-AC is Pt95Co5 heat treated to AC — pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation. Pt95Co5-AC has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Elongation at break is 20% and the elastic modulus is 168 GPa (24.4 Msi). Pt95Co5-AC has a density of 20 g/cm³ (0.723 lb/in³), heavier than 93% of precious metal grades. It melts at 1,745°C (3,173 °F).
Advantages
- Readily welded — 85/100, better than 93% of precious metal grades
- High service temperature — 800°C (1,472 °F), better than 90% of precious metal grades
- Stiff — 168 GPa (24.4 Msi), better than 89% of precious metal grades
- Good corrosion resistance — 96/100, better than 85% of precious metal grades
- High strength — 250 MPa (36.3 ksi), better than 81% of precious metal grades
Limitations
- Heavy — 20 g/cm³ (0.723 lb/in³), worse than 93% of precious metal grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 89% of precious metal grades
- Low electrical conductivity — 7 % IACS, worse than 89% of precious metal grades
- Limited formability — 55/100, worse than 89% of precious metal grades
- High embodied carbon — 13,000 kg CO₂/kg, worse than 81% of precious metal grades
Pt95Co5-AC properties
Typical room-temperature values for Pt95Co5-AC; 20 are specific to this condition. Other listed values are Pt95Co5 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
Pt95Co5-AC has a density of 20 g/cm³ (0.723 lb/in³), heavier than 93% of precious metal grades. It melts at 1,745°C (3,173 °F).
Mechanical14
Pt95Co5-AC has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Elongation at break is 20% and the elastic modulus is 168 GPa (24.4 Msi).
Thermal6
Pt95Co5-AC is rated for continuous service to 800°C (1,472 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 89% of precious metal grades. Thermal expansion is 9.2 µm/m·K (5.11 µin/in·°F).
Electrical3
Pt95Co5-AC conducts electricity at 7 % IACS, worse than 89% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (96/100), better than 85% of precious metal grades.
Sustainability4
Producing a kilogram of Pt95Co5-AC takes about 250,000 MJ of energy and emits 13,000 kg of CO₂ — more than 95% of precious metal grades. Typical recycled content is 35%.
Manufacturability8
Pt95Co5-AC's machinability is fair (35/100, worse than 73% of precious metal grades); weldability excellent (85/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Pt95Co5-AC
Is Pt95Co5 easy to machine?
Tough and gummy with a tendency to build-up edge — use sharp, high positive-rake carbide or diamond tooling at low speed with light feeds and ample lubricant. Single-point diamond turning gives a mirror surface on jewelry parts.
Can Pt95Co5 be welded?
Laser and PUK pulse-arc welding work well with matching Pt950Co filler wire. With oxy-acetylene, keep the flame slightly reducing to limit cobalt oxidation and avoid overheating, which coarsens the grain.
Can Pt95Co5 be formed, bent or molded?
Investment casting is the primary route: mould temperature 850–1000 °C, pour at 1800–1850 °C, induction vacuum or centrifugal. Castings can be annealed and cold formed; interanneal once cold work exceeds about 40 %.
What surface finishes work on Pt95Co5?
Polishes more quickly than Pt950Ru; step through silicon carbide, then alumina, then chromium oxide for a mirror finish. Rhodium plating is not required, though a thin rhodium flash can be applied for an extra-white tone; blasted and brushed textures remain stable and do not tarnish.
Pt95Co5 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 |
|---|---|---|
| Cosolid-solution strengthener; casting flow, fine grain, weak magnetism | 4.5 – 5.5 | 5 |
| Other (Ir, Ru, Cu, Fe )total impurities, normally well below 0.1% | ≤ 0.5 | — |
| Pt950 hallmark requires ≥95.0% Pt (GB 11887 / ISO 9202) | ≥ 95 (balance) | — |
Pt95Co5-AC — frequently asked
What is Pt95Co5-AC used for?
Pt95Co5-AC is typically used for cast platinum jewelry, ring settings and watch cases. In short: standard platinum casting alloy; fast-polishing Pt950 grade; bright white at 950 fineness.
What is the yield strength of Pt95Co5-AC?
Pt95Co5-AC has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Strength varies by condition: see the 5 listed tempers.
Is Pt95Co5-AC easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Tough and gummy with a tendency to build-up edge — use sharp, high positive-rake carbide or diamond tooling at low speed with light feeds and ample lubricant. Single-point diamond turning gives a mirror surface on jewelry parts.
Can Pt95Co5-AC be welded?
Yes — weldability is rated excellent (85/100). Laser and PUK pulse-arc welding work well with matching Pt950Co filler wire. With oxy-acetylene, keep the flame slightly reducing to limit cobalt oxidation and avoid overheating, which coarsens the grain.
What surface finishes work on Pt95Co5-AC?
Polishes more quickly than Pt950Ru; step through silicon carbide, then alumina, then chromium oxide for a mirror finish. Rhodium plating is not required, though a thin rhodium flash can be applied for an extra-white tone; blasted and brushed textures remain stable and do not tarnish.
Can Pt95Co5-AC be formed, bent or molded?
Investment casting is the primary route: mould temperature 850–1000 °C, pour at 1800–1850 °C, induction vacuum or centrifugal. Castings can be annealed and cold formed; interanneal once cold work exceeds about 40 %.
What is the maximum service temperature of Pt95Co5-AC?
Pt95Co5-AC is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Pt95Co5-AC and Pt95Co5-H04?
AC is the default condition — pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation. H04: choose heavily cold-worked wire or strip (50%+ reduction) for spring clasps and earring posts where hardness and springiness are highest; elongation drops to 3%. Yield strength is 250 MPa in AC versus 620 MPa in H04.
Sources
- ISO 9202 Jewellery — Fineness of precious metal alloys — ISO (2019)
- Platinum Metals Review — platinum jewellery alloys (properties of Pt-Co, Pt-Ru, Pt-Ir) — Johnson Matthey (2005)
- ASM Handbook Vol. 2 — Properties of Precious Metals and Alloys — ASM International (1990)
- Platinum casting alloy technical data (Pt950/Co) — Hoover & Strong / Stuller (2023)
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.