Copper Alloy C15900-SR900
Heat-treated state
UNS C15900
SR900 = cold worked then stress relieved / brazing-cycle exposed
Represents the property level after vacuum brazing or high-temperature stress relief — chosen when the part must be joined or thermally cycled and still carry load.
Values for the SR900 condition
Other C15900 tempers and conditions
C15900 is listed in 7 conditions; see the grade overview at C15900.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot isostatic pressed | Consolidated powder billet supplied for customers who will forge, extrude or back-extrude the part themselves. | 310 | 400 | 22 | 105 HB | 86 % IACS |
As hot extruded | Pick for large-section bar, forging stock and parts that will be heavily machined or subsequently hot worked. | 370 | 450 | 20 | 118 HB | 86 % IACS |
SR900This page Cold worked then stress relieved / brazing-cycle exposed | Represents the property level after vacuum brazing or high-temperature stress relief — chosen when the part must be joined or thermally cycled and still carry load. | 395 | 470 | 18 | 125 HB | 86 % IACS |
Quarter hard | Compromise temper when some bending/staking is still required but higher yield than mill condition is wanted. | 430 | 490 | 16 | 130 HB | 85 % IACS |
Half hard | Typical for strip, small rod and contact supports needing balanced strength and residual ductility. | 470 | 515 | 14 | 138 HB | 85 % IACS |
H04Default Full hard | Standard stocked condition for resistance-welding electrodes, high heat-flux inserts and structural conductors. | 505 | 550 | 12 | 145 HB | 85 % IACS |
Spring hard | Highest strength condition, used for fine wire, contact springs and small-diameter conductors. | 570 | 610 | 8 | 160 HB | 84 % IACS |
What is C15900-SR900?
C15900-SR900 is C15900 heat treated to SR900 — represents the property level after vacuum brazing or high-temperature stress relief — chosen when the part must be joined or thermally cycled and still carry load. C15900-SR900 has a yield strength of 395 MPa (57.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 79% of copper alloy grades. Elongation at break is 18% and the elastic modulus is 130 GPa (18.9 Msi). C15900-SR900 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,083°C (1,981 °F). H04 is the default condition FabDigit quotes; SR900 is available on request or by drawing note.
Advantages
- High service temperature — 600°C (1,112 °F), better than 100% of copper alloy grades
- Stiff — 130 GPa (18.9 Msi), better than 89% of copper alloy grades
- High electrical conductivity — 86 % IACS, better than 86% of copper alloy grades
- Conducts heat well — 334 W/m·K (193 BTU/hr·ft·°F), better than 85% of copper alloy grades
- High strength — 395 MPa (57.3 ksi), better than 79% of copper alloy grades
Limitations
- Hard to polish — 65/100, worse than 87% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C15900-SR900 properties
Typical room-temperature values for C15900-SR900; 10 are specific to this condition. Other listed values are C15900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C15900-SR900 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,083°C (1,981 °F).
Mechanical13
C15900-SR900 has a yield strength of 395 MPa (57.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 79% of copper alloy grades. Elongation at break is 18% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal6
C15900-SR900 is rated for continuous service to 600°C (1,112 °F). It conducts heat at 334 W/m·K (193 BTU/hr·ft·°F), better than 85% of copper alloy grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
C15900-SR900 conducts electricity at 86 % IACS, better than 86% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of C15900-SR900 takes about 65 MJ of energy and emits 4.2 kg of CO₂ — more than 81% of copper alloy grades. Typical recycled content is 5%.
Manufacturability7
C15900-SR900's machinability is fair (35/100, better than 51% of copper alloy grades); weldability poor (25/100); formability fair (48/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C15900-SR900
Is C15900 easy to machine?
Machines like tough copper but the Al₂O₃ is abrasive — use sharp, polished uncoated carbide or PCD, positive rake, high speed with flood coolant, and expect 3–5× the tool wear of C11000.
Can C15900 be welded?
Avoid fusion welding (GTAW/GMAW) — melting agglomerates the dispersoid and causes porosity; join by vacuum/furnace brazing, electron-beam, friction or resistance welding, all of which leave the base metal strength intact.
Can C15900 be formed, bent or molded?
Cold form only with generous radii and limited reduction per pass; hot working (700–900 °C extrusion/forging) is the normal route and does not soften the material.
What surface finishes work on C15900?
Not anodisable; electroplate Ni, Ag or hard Cr for wear/oxidation protection, or leave bare with periodic oxide removal — polishes to a copper lustre but the dispersoid can leave a slightly matte finish.
C15900 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 |
|---|---|---|
| Alpresent as internally-oxidised Al₂O₃ dispersoid (≈0.4–1.1 wt% Al₂O₃), not in solid solution | 0.2 – 0.6 | 0.35 |
| Ocombined as Al₂O₃; residual free oxygen kept low | 0.15 – 0.55 | 0.3 |
| Other (each)incidental impurities from powder route | ≤ 0.05 | — |
| Cumatrix, high-purity oxygen-free copper | balance | — |
C15900-SR900 — frequently asked
What is C15900-SR900 used for?
C15900-SR900 is typically used for resistance welding electrodes, rocket engine combustion chamber liners and high-temperature electrical contacts. In short: highest-temperature conductive copper; non-softening to 500 °C; dispersion-strengthened, not age-hardened.
What is the yield strength of C15900-SR900?
C15900-SR900 has a typical yield strength of 395 MPa (57.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 79% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C15900-SR900 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Machines like tough copper but the Al₂O₃ is abrasive — use sharp, polished uncoated carbide or PCD, positive rake, high speed with flood coolant, and expect 3–5× the tool wear of C11000.
Can C15900-SR900 be welded?
Not readily — weldability is rated poor (25/100). Avoid fusion welding (GTAW/GMAW) — melting agglomerates the dispersoid and causes porosity; join by vacuum/furnace brazing, electron-beam, friction or resistance welding, all of which leave the base metal strength intact.
What surface finishes work on C15900-SR900?
Not anodisable; electroplate Ni, Ag or hard Cr for wear/oxidation protection, or leave bare with periodic oxide removal — polishes to a copper lustre but the dispersoid can leave a slightly matte finish.
Can C15900-SR900 be formed, bent or molded?
Cold form only with generous radii and limited reduction per pass; hot working (700–900 °C extrusion/forging) is the normal route and does not soften the material.
What is the maximum service temperature of C15900-SR900?
C15900-SR900 is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C15900-H04 and C15900-HIP?
H04 is the default condition — standard stocked condition for resistance-welding electrodes, high heat-flux inserts and structural conductors. HIP: consolidated powder billet supplied for customers who will forge, extrude or back-extrude the part themselves. Yield strength is 505 MPa in H04 versus 310 MPa in HIP.
Sources
- ASTM B902 — Compacted and Sintered Dispersion-Strengthened Copper Structural Materials — ASTM International (2020)
- CDA/UNS Copper Alloy Registration — C159xx dispersion-strengthened coppers — Copper Development Association (2023)
- GlidCop Dispersion Strengthened Copper AL-15 / AL-25 / AL-60 property data — SCM Metal Products / Höganäs (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
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.