Precious Metal Pt90Ir10-SR (Stress relieved)
Heat-treated state
ASTM B562 · EN PtIr10
Used to stabilise dimensions and reduce spring-back in formed electrodes/standards while retaining most cold-work strength.
Values for the SR condition
Other Pt90Ir10 tempers and conditions
Pt90Ir10 is listed in 6 conditions; see the grade overview at Pt90Ir10.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault fully softened (≈1000–1200 °C, air or H2) | Standard stocked condition for wire, ribbon, sheet and tubing that must be formed, coiled, swaged or welded. | 210 | 380 | 27 | 105 HB | — |
Quarter hard | Pick when parts still need mild bending but require more spring-back control and handling stiffness than soft temper. | 420 | 550 | 12 | 143 HB | 6.8 % IACS |
SRThis page Stress relieved | Used to stabilise dimensions and reduce spring-back in formed electrodes/standards while retaining most cold-work strength. | 480 | 620 | 10 | 166 HB | 6.9 % IACS |
Half hard | Compromise temper for marker bands, contacts and stamped parts needing strength with some residual ductility. | 570 | 700 | 6 | 180 HB | 6.7 % IACS |
Full hard | Choose for stiff guidewires, probe tips, pen nib tipping stock and electrodes needing maximum strength and wear resistance. | 830 | 950 | 2.5 | 23 HRC | 6.6 % IACS |
Spring hard | Fine wire for springs, coils and stylus/contact elements where elastic limit matters more than ductility. | 930 | 1,050 | 1.5 | 28 HRC | 6.5 % IACS |
What is Pt90Ir10-SR?
Pt90Ir10-SR is Pt90Ir10 heat treated to SR — used to stabilise dimensions and reduce spring-back in formed electrodes/standards while retaining most cold-work strength. Pt90Ir10-SR has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 97% of precious metal grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi). Pt90Ir10-SR has a density of 21.54 g/cm³ (0.778 lb/in³), heavier than 99% of precious metal grades. It melts at 1,780°C (3,236 °F). Annealed is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High strength — 480 MPa (69.6 ksi), better than 97% of precious metal grades
- Stiff — 200 GPa (29 Msi), better than 97% of precious metal grades
- Good corrosion resistance — 99/100, better than 93% of precious metal grades
- High service temperature — 800°C (1,472 °F), better than 90% of precious metal grades
Limitations
- Heavy — 21.54 g/cm³ (0.778 lb/in³), worse than 99% of precious metal grades
- Poor heat conductor — 30.8 W/m·K (17.8 BTU/hr·ft·°F), worse than 93% of precious metal grades
- High embodied carbon — 14,500 kg CO₂/kg, worse than 92% of precious metal grades
- Low electrical conductivity — 6.9 % IACS, worse than 90% of precious metal grades
- Difficult to machine — 29/100, worse than 90% of precious metal grades
Pt90Ir10-SR properties
Typical room-temperature values for Pt90Ir10-SR; 19 are specific to this condition. Other listed values are Pt90Ir10 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
Pt90Ir10-SR has a density of 21.54 g/cm³ (0.778 lb/in³), heavier than 99% of precious metal grades. It melts at 1,780°C (3,236 °F).
Mechanical11
Pt90Ir10-SR has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 97% of precious metal grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
Pt90Ir10-SR is rated for continuous service to 800°C (1,472 °F). It conducts heat at 30.8 W/m·K (17.8 BTU/hr·ft·°F), worse than 93% of precious metal grades. Thermal expansion is 8.8 µm/m·K (4.89 µin/in·°F).
Electrical3
Pt90Ir10-SR conducts electricity at 6.9 % IACS, worse than 90% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (99/100), better than 93% of precious metal grades.
Sustainability4
Producing a kilogram of Pt90Ir10-SR takes about 250,000 MJ of energy and emits 14,500 kg of CO₂ — more than 95% of precious metal grades. Typical recycled content is 45%.
Manufacturability8
Pt90Ir10-SR's machinability is poor (29/100, worse than 90% of precious metal grades); weldability good (68/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Pt90Ir10-SR
Is Pt90Ir10 easy to machine?
Very gummy and rapidly work-hardening: use sharp, high-positive-rake carbide or PCD tools, light-but-positive feeds, flood coolant, and collect all swarf/coolant for refining.
Can Pt90Ir10 be welded?
Excellent for resistance, laser and micro-TIG welding autogenously in argon; keep the joint clean of sulphur, lead, silicon and carbon contamination which cause hot cracking.
Can Pt90Ir10 be formed, bent or molded?
Highly ductile when annealed — cold drawn to <25 µm wire and rolled to thin foil, with interstage anneals near 1000–1100 °C after roughly 60–75 % reduction.
What surface finishes work on Pt90Ir10?
Polishes to a durable mirror without tarnish or plating; electropolishing, Pt-black deposition or laser texturing are used on electrode surfaces; no anodizing or protective coating needed.
Pt90Ir10 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 |
|---|---|---|
| Irsolid-solution hardener | 9.5 – 10.5 | 10 |
| Other PGM + base metals (total)Rh, Pd, Ru, Fe, Cu, Ni impurities; high-purity grades ≤0.05 % | ≤ 0.1 | 0.05 |
| Pt | ≥ 89.4 (balance) | — |
Pt90Ir10-SR — frequently asked
What is Pt90Ir10-SR used for?
Pt90Ir10-SR is typically used for fountain pen nib tipping, spark plug electrodes, surgical wire and reference standards. In short: hardest common Pt-Ir grade; tarnish-free to 1200 °C; reference-standard platinum alloy.
What is the yield strength of Pt90Ir10-SR?
Pt90Ir10-SR has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 97% of precious metal grades. Strength varies by condition: see the 6 listed tempers.
Is Pt90Ir10-SR easy to machine?
Not especially — machinability is rated poor (29/100, worse than 90% of precious metal grades). Very gummy and rapidly work-hardening: use sharp, high-positive-rake carbide or PCD tools, light-but-positive feeds, flood coolant, and collect all swarf/coolant for refining.
Can Pt90Ir10-SR be welded?
Yes — weldability is rated good (68/100). Excellent for resistance, laser and micro-TIG welding autogenously in argon; keep the joint clean of sulphur, lead, silicon and carbon contamination which cause hot cracking.
What surface finishes work on Pt90Ir10-SR?
Polishes to a durable mirror without tarnish or plating; electropolishing, Pt-black deposition or laser texturing are used on electrode surfaces; no anodizing or protective coating needed.
Can Pt90Ir10-SR be formed, bent or molded?
Highly ductile when annealed — cold drawn to <25 µm wire and rolled to thin foil, with interstage anneals near 1000–1100 °C after roughly 60–75 % reduction.
What is the maximum service temperature of Pt90Ir10-SR?
Pt90Ir10-SR 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 Pt90Ir10 Annealed and Pt90Ir10 Spring?
Annealed is the default condition — standard stocked condition for wire, ribbon, sheet and tubing that must be formed, coiled, swaged or welded. Spring: fine wire for springs, coils and stylus/contact elements where elastic limit matters more than ductility. Yield strength is 210 MPa in Annealed versus 930 MPa in Spring.
Sources
- ASTM B562 — Refined Platinum — ASTM International (2020)
- ASTM F2181 / F560-family specifications for implantable precious-metal wire — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Precious Metals) — ASM International (1990)
- Platinum-Iridium alloy technical data — Johnson Matthey Noble Metals (2022)
- Precious metal alloys for medical and electrical applications — Heraeus / Deringer-Ney (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.