Copper Alloy C61600-OS025
Temper
UNS C61600 · ASTM B111
OS025 = annealed to 0.025 mm grain size
Grain-size-controlled soft anneal when deep drawing or tight U-bends demand uniform, fine-grained ductility.
Values for the OS025 condition
Other C61600 tempers and conditions
C61600 is listed in 8 conditions; see the grade overview at C61600.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OS025This page Annealed to 0.025 mm grain size | Grain-size-controlled soft anneal when deep drawing or tight U-bends demand uniform, fine-grained ductility. | 155 | 385 | 60 | 72 HB | 18 % IACS |
O61Default Annealed | Standard condition for seawater condenser and heat-exchanger tubing; maximum ductility for expanding into tubesheets and U-bending. | 170 | 400 | 55 | 80 HB | 18 % IACS |
Quarter hard | Mild cold work for formed parts needing more strength than annealed while still bending readily. | 240 | 430 | 40 | 112 HB | 18 % IACS |
Light drawn | Light draw pass for straightness and dimensional control while keeping enough ductility for tube expansion. | 275 | 450 | 35 | 110 HB | 18 % IACS |
Drawn, general purpose | General-purpose drawn tube temper: good balance of strength, straightness and residual ductility. | 340 | 480 | 25 | 132 HB | 18 % IACS |
Drawn and stress-relieved | Drawn tube given a low-temperature stress relief to cut residual stress before service in ammonia-bearing or high-stress environments. | 380 | 500 | 20 | 142 HB | 18 % IACS |
Half hard | Common stock condition for machined fittings, sleeves and fasteners where moderate strength is needed. | 400 | 515 | 20 | 150 HB | 17.5 % IACS |
Full hard | Highest cold-worked strength; choose for wear sleeves, shafting and high-pressure tubing where forming is minimal. | 470 | 585 | 10 | 9 HRC | 17 % IACS |
What is C61600-OS025?
C61600-OS025 is C61600 in the OS025 temper — grain-size-controlled soft anneal when deep drawing or tight U-bends demand uniform, fine-grained ductility. C61600-OS025 has a yield strength of 155 MPa (22.5 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 65% of copper alloy grades. Elongation at break is 60% and the elastic modulus is 117 GPa (17 Msi). C61600-OS025 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 85% of copper alloy grades. It melts at 1,040°C (1,904 °F). O61 is the default condition FabDigit quotes; OS025 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 60%, better than 99% of copper alloy grades
- Readily welded — 75/100, better than 89% of copper alloy grades
- Forms and bends easily — 88/100, better than 87% of copper alloy grades
- Good corrosion resistance — 72/100, better than 84% of copper alloy grades
Limitations
- Hard to polish — 65/100, worse than 87% of copper alloy grades
C61600-OS025 properties
Typical room-temperature values for C61600-OS025; 20 are specific to this condition. Other listed values are C61600 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C61600-OS025 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 85% of copper alloy grades. It melts at 1,040°C (1,904 °F).
Mechanical11
C61600-OS025 has a yield strength of 155 MPa (22.5 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 65% of copper alloy grades. Elongation at break is 60% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C61600-OS025 is rated for continuous service to 250°C (482 °F). It conducts heat at 88 W/m·K (50.8 BTU/hr·ft·°F), better than 53% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C61600-OS025 conducts electricity at 18 % IACS, better than 51% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 84% of copper alloy grades.
Sustainability4
Producing a kilogram of C61600-OS025 takes about 52 MJ of energy and emits 3.6 kg of CO₂ — less than 87% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C61600-OS025's machinability is poor (34/100, worse than 53% of copper alloy grades); weldability very good (75/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C61600-OS025
Is C61600 easy to machine?
Machines like a tough, gummy bronze — rigid setups, positive-rake sharp carbide, moderate speed with generous coolant; expect ~30 % of free-cutting brass throughput and stringy chips.
Can C61600 be welded?
GTAW/GMAW with aluminum-bronze filler works well; keep interpass temperature low, clean the Al-oxide film with stainless brush, avoid oxyacetylene and heavy heat input.
Can C61600 be formed, bent or molded?
Excellent cold formability in O61/OS tempers — tube expanding, U-bending and deep drawing are routine; anneal ~600–650 °C between heavy passes.
What surface finishes work on C61600?
Not anodizable; takes fine polishing and develops a protective dull-bronze film in service. FeSO₄ dosing or clean-water start-up is standard for condenser tubes; electroplating requires careful oxide removal.
C61600 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 |
|---|---|---|
| Allow-aluminum bronze range; confirm exact registered limits against the current CDA/UNS sheet before ordering | 2.5 – 3.5 | 3 |
| Cubalance, plus small residual Fe/Ni/Si/Zn/Pb/Mn impurity limits per the governing product standard | balance | — |
C61600-OS025 — frequently asked
What is C61600-OS025 used for?
C61600-OS025 is typically used for condenser tubes, heat exchanger tubing, marine piping and distiller tubes. In short: seawater condenser tube alloy; most formable aluminum bronze; corrosion over strength.
What is the yield strength of C61600-OS025?
C61600-OS025 has a typical yield strength of 155 MPa (22.5 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 65% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C61600-OS025 easy to machine?
Not especially — machinability is rated poor (34/100, worse than 53% of copper alloy grades). Machines like a tough, gummy bronze — rigid setups, positive-rake sharp carbide, moderate speed with generous coolant; expect ~30 % of free-cutting brass throughput and stringy chips.
Can C61600-OS025 be welded?
Yes — weldability is rated very good (75/100). GTAW/GMAW with aluminum-bronze filler works well; keep interpass temperature low, clean the Al-oxide film with stainless brush, avoid oxyacetylene and heavy heat input.
What surface finishes work on C61600-OS025?
Not anodizable; takes fine polishing and develops a protective dull-bronze film in service. FeSO₄ dosing or clean-water start-up is standard for condenser tubes; electroplating requires careful oxide removal.
Can C61600-OS025 be formed, bent or molded?
Excellent cold formability in O61/OS tempers — tube expanding, U-bending and deep drawing are routine; anneal ~600–650 °C between heavy passes.
What is the maximum service temperature of C61600-OS025?
C61600-OS025 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C61600-O61 and C61600-H04?
O61 is the default condition — standard condition for seawater condenser and heat-exchanger tubing; maximum ductility for expanding into tubesheets and U-bending. H04: highest cold-worked strength; choose for wear sleeves, shafting and high-pressure tubing where forming is minimal. Yield strength is 170 MPa in O61 versus 470 MPa in H04.
Sources
- ASTM B111/B111M — Seamless Copper and Copper-Alloy Condenser Tubes and Ferrule Stock — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Aluminum bronzes) — ASM International (1990)
- CDA/UNS Copper Alloy Data Sheets (C6xxxx wrought aluminum bronzes) — Copper Development Association (2023)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
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.