Precious Metal Pt950/Pt900/Pt850 Pt950Ru-Ann
Grade · default condition
GB 11887 · ISO 9202
Pt950Ru-Ann = pt950/Ru
The workhorse Pt950 for hand fabrication, wire, tubing and general casting — good hardness/ductility balance and bright white colour.
Values for the Pt950Ru-Ann condition
Other Pt950/Pt900/Pt850 tempers and conditions
Pt950/Pt900/Pt850 is listed in 11 conditions; see the grade overview at Pt950/Pt900/Pt850.
- Pt999-Ann
- Pt900Pd-Ann
- Pt850Pd-Ann
- Pt950Cu-Ann
- Pt950Ir-Ann
- Pt950Ru-Ann
- Pt900Ir-Ann
- Pt950Co-Cast
- Pt950W-Ann
- Pt850Ir-Ann
- Pt950Ru-H
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Pt999 (fine platinum, ≥99.9% Pt), annealed | Pick annealed unalloyed fine platinum for investment bars, granulation and highest-purity items; 45% elongation and 40 HB give maximum ductility but are far too soft for stone-set jewellery. | 55 | 145 | 45 | 40 HB | 16.3 % IACS |
Pt900/Pd | Lightest and softest Pt900 option — chosen to cut weight and cost in large hollow pieces, at the price of poor scratch resistance. | 100 | 220 | 38 | 78 HB | 9.5 % IACS |
Pt850/Pd | Economy Pt850 for chain, hollow and lightweight goods where cost and formability outweigh hardness. | 130 | 280 | 33 | 100 HB | 7 % IACS |
Pt950/Cu | Low-cost Pt950 used widely in Asian chain and light jewellery; easy to melt and form but softest and slightly warmer in colour. | 140 | 310 | 32 | 110 HV | — |
Pt950/Ir | Softest of the common Pt950 alloys — pick for hand-forming, bezels and easy stone setting where maximum ductility matters. | 150 | 320 | 38 | 110 HV | — |
Pt950Ru-AnnDefaultThis page Pt950/Ru | The workhorse Pt950 for hand fabrication, wire, tubing and general casting — good hardness/ductility balance and bright white colour. | 190 | 400 | 35 | 130 HV | 40 W/m·K |
Pt900/Ir | Classic hard-wearing fineness for prong settings, wedding bands and antique-style mountings; noticeably stiffer than Pt950. | 200 | 380 | 28 | 130 HV | 6.9 % IACS |
Pt950/Co | The standard investment-casting Pt950: best fluidity and fine detail reproduction, but slightly magnetic and prone to grey polishing smut. | 230 | 420 | 20 | 135 HV | — |
Pt950/W | Higher-strength Pt950 for thin wire, spring elements and wear surfaces; harder to melt and less forgiving in casting. | 260 | 480 | 25 | 140 HB | 4 % IACS |
Pt850/Ir | Hardest standard jewellery fineness (also used for medical wire and electrodes) — best wear and prong retention, hardest to work. | 260 | 480 | 22 | 160 HV | 5.4 % IACS |
Pt950/Ru | Choose for spring clasps, thin wire, pin stems and any part needing scratch resistance without heat treatment. | 600 | 700 | 3 | 19 HRC | 5.5 % IACS |
What is Pt950/Pt900/Pt850 Pt950Ru-Ann?
Pt950/Pt900/Pt850 Pt950Ru-Ann is Pt950/Pt900/Pt850 in the Pt950Ru-Ann grade — the workhorse Pt950 for hand fabrication, wire, tubing and general casting — good hardness/ductility balance and bright white colour. Pt950/Pt900/Pt850 Pt950Ru-Ann has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 56% of precious metal grades. Elongation at break is 35% and the elastic modulus is 175 GPa (25.4 Msi). Pt950/Pt900/Pt850 Pt950Ru-Ann has a density of 20.7 g/cm³ (0.748 lb/in³), heavier than 96% of precious metal grades. It melts at 1,780°C (3,236 °F).
Advantages
- Readily welded — 90/100, better than 99% of precious metal grades
- High service temperature — 1,000°C (1,832 °F), better than 95% of precious metal grades
- Good corrosion resistance — 99/100, better than 93% of precious metal grades
- Stiff — 175 GPa (25.4 Msi), better than 91% of precious metal grades
- Ductile — tolerates forming and impact — 35%, better than 83% of precious metal grades
Limitations
- High embodied carbon — 30,000 kg CO₂/kg, worse than 100% of precious metal grades
- Heavy — 20.7 g/cm³ (0.748 lb/in³), worse than 96% of precious metal grades
- Low electrical conductivity — 5.7 % IACS, worse than 93% of precious metal grades
- Poor heat conductor — 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 85% of precious metal grades
Pt950/Pt900/Pt850 Pt950Ru-Ann properties
Typical room-temperature values for Pt950/Pt900/Pt850 Pt950Ru-Ann; 14 are specific to this condition. Other listed values are Pt950/Pt900/Pt850 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
Pt950/Pt900/Pt850 Pt950Ru-Ann has a density of 20.7 g/cm³ (0.748 lb/in³), heavier than 96% of precious metal grades. It melts at 1,780°C (3,236 °F).
Mechanical11
Pt950/Pt900/Pt850 Pt950Ru-Ann has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 56% of precious metal grades. Elongation at break is 35% and the elastic modulus is 175 GPa (25.4 Msi).
Thermal6
Pt950/Pt900/Pt850 Pt950Ru-Ann is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 85% of precious metal grades. Thermal expansion is 9 µm/m·K (5 µin/in·°F).
Electrical3
Pt950/Pt900/Pt850 Pt950Ru-Ann conducts electricity at 5.7 % IACS, worse than 93% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (99/100), better than 93% of precious metal grades.
Sustainability4
Producing a kilogram of Pt950/Pt900/Pt850 Pt950Ru-Ann takes about 300,000 MJ of energy and emits 30,000 kg of CO₂ — more than 99% of precious metal grades. Typical recycled content is 28%.
Manufacturability8
Pt950/Pt900/Pt850 Pt950Ru-Ann's machinability is fair (35/100, worse than 73% of precious metal grades); weldability excellent (90/100); 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 Pt950/Pt900/Pt850 Pt950Ru-Ann
Is Pt950/Pt900/Pt850 easy to machine?
Soft and gummy — use sharp, high-rake carbide or HSS tools, light depths, high speed with flood lube, and capture all swarf for refining.
Can Pt950/Pt900/Pt850 be welded?
Excellent: pulsed laser or oxy-hydrogen/oxy-acetylene fusion welding without flux; Pt solders (Pt-Au-Pd) available for graded joining temperatures.
Can Pt950/Pt900/Pt850 be formed, bent or molded?
Very ductile when annealed (anneal 1000–1200 °C, air cool); casting needs induction/centrifugal melting above ~1800 °C with phosphate-bonded investment and zirconia crucibles.
What surface finishes work on Pt950/Pt900/Pt850?
Polishes to a durable bright white without plating; use platinum-specific compounds and diamond pre-polish because the metal smears rather than cuts, and reclaim polishing dust.
Pt950/Pt900/Pt850 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 |
|---|---|---|
| Rudefault Pt950/Ru alloy addition | 4.5 – 5.5 | 5 |
| Ir5% in Pt950/Ir, 10% in Pt900/Ir, 15% in Pt850/Ir | 0 – 15 | — |
| Cocasting alloy Pt950/Co; renders alloy weakly magnetic | 0 – 5 | — |
| Cueconomy Pt950/Cu and Pt850 variants | 0 – 15 | — |
| PdPt900/Pd, Pt850/Pd lightweight variants | 0 – 15 | — |
| WPt950/W high-strength wire variant | 0 – 5 | — |
| Gaoccasionally used with Cu/Co to lower melting range for casting | 0 – 2 | — |
| PtPt950 ≥95.0%; Pt900 ≥90.0%; Pt850 ≥85.0% per GB 11887 / ISO 9202 fineness marks | ≥ 95 (balance) | — |
Pt950/Pt900/Pt850 Pt950Ru-Ann — frequently asked
What is Pt950/Pt900/Pt850 Pt950Ru-Ann used for?
Pt950/Pt900/Pt850 Pt950Ru-Ann is typically used for rings, bridal jewelry, watch cases and investment casting jewelry. In short: densest common jewelry metal; white without rhodium plating; flux-free fusion welding.
What is the yield strength of Pt950/Pt900/Pt850 Pt950Ru-Ann?
Pt950/Pt900/Pt850 Pt950Ru-Ann has a typical yield strength of 190 MPa (27.6 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 56% of precious metal grades. Strength varies by condition: see the 11 listed tempers.
Is Pt950/Pt900/Pt850 Pt950Ru-Ann easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Soft and gummy — use sharp, high-rake carbide or HSS tools, light depths, high speed with flood lube, and capture all swarf for refining.
Can Pt950/Pt900/Pt850 Pt950Ru-Ann be welded?
Yes — weldability is rated excellent (90/100). Excellent: pulsed laser or oxy-hydrogen/oxy-acetylene fusion welding without flux; Pt solders (Pt-Au-Pd) available for graded joining temperatures.
What surface finishes work on Pt950/Pt900/Pt850 Pt950Ru-Ann?
Polishes to a durable bright white without plating; use platinum-specific compounds and diamond pre-polish because the metal smears rather than cuts, and reclaim polishing dust.
Can Pt950/Pt900/Pt850 Pt950Ru-Ann be formed, bent or molded?
Very ductile when annealed (anneal 1000–1200 °C, air cool); casting needs induction/centrifugal melting above ~1800 °C with phosphate-bonded investment and zirconia crucibles.
What is the maximum service temperature of Pt950/Pt900/Pt850 Pt950Ru-Ann?
Pt950/Pt900/Pt850 Pt950Ru-Ann is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ISO 9202 Jewellery — Fineness of precious metal alloys — ISO (2019)
- ASM Handbook Vol.2 — Properties of Precious Metals and Alloys — ASM International (1990)
- Noble metal alloy data (Pt-Ru, Pt-Ir, Pt-Co jewellery alloys) — Johnson Matthey (2020)
- Platinum Metals Review — platinum jewellery alloy properties — Johnson Matthey (2002)
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.