Copper Alloy C68300
UNS C68300
C68300 is an antimony- and silicon-modified wrought brass engineered for dezincification resistance in plumbing and marine tube service.
Reference datasheet — C68300 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the O61 condition
C68300 tempers and conditions
C68300 is supplied in 11 conditions, soft to hard. O61 is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.050 mm grain size | Coarse-grain soft anneal for maximum drawability in severe forming of cups and fittings. | 95 | 320 | 60 | 53 HB | 30 % IACS |
O61Default Annealed | Standard stocked soft condition for tube bending, expanding into tubesheets and deep drawing. | 105 | 330 | 55 | 58 HB | 30 % IACS |
Annealed to 0.025 mm grain size | Fine-grain soft anneal giving smoother surfaces after forming and slightly higher strength. | 120 | 345 | 52 | 63 HB | 30 % IACS |
Annealed to 0.015 mm grain size | Very fine grain soft temper where orange-peel must be avoided on visible formed surfaces. | 140 | 360 | 48 | 70 HB | 30 % IACS |
Light drawn tube | Light draw for straight condenser/heat-exchanger tube that still needs to be expanded into tubesheets. | 215 | 370 | 35 | 80 HB | 29 % IACS |
Quarter hard | Light cold work for flat products needing stiffness while retaining good bending. | 240 | 380 | 38 | 85 HB | 30 % IACS |
Drawn and stress-relieved tube | Cold-drawn then low-temperature stress relieved to minimise residual-stress SCC risk in ammonia-bearing service. | 250 | 385 | 30 | 88 HB | 30 % IACS |
Drawn, general purpose tube | General-purpose drawn tube temper for plumbing and pressure lines with moderate bending. | 260 | 395 | 28 | 90 HB | 29 % IACS |
Half hard | Balanced strength/formability temper for stamped fittings and formed components. | 320 | 425 | 23 | 110 HB | 29.5 % IACS |
Hard drawn | Hard-drawn tube for maximum pressure rating and straightness where no further forming is required. | 380 | 460 | 10 | 130 HB | 29 % IACS |
Full hard | Fully hard temper for springy flat parts and maximum strength with minimal forming. | 410 | 490 | 8 | 140 HB | 29 % IACS |
What is C68300?
C68300 is an antimony- and silicon-modified wrought brass engineered for dezincification resistance in plumbing and marine tube service. In the annealed condition it runs 330 MPa tensile, 105 MPa yield and 55 % elongation at 58 HB (35 HRB), with a formability rating of 95, so it draws, bends and expands into tubesheets readily; usual forms are seamless tube and drawn strip. Being unleaded, machinability is only about 30 % of free-cutting brass, conductivity is 30 % IACS, and arc welding is limited by zinc fuming. For seawater condenser duty, C68700 is the common alternative. C68300 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 927°C (1,701 °F). C68300 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 55% and the elastic modulus is 110 GPa (16 Msi).
What is C68300 used for?
- condenser tubes
- plumbing tube
- marine tubing
Advantages
- Ductile — tolerates forming and impact — 55%, better than 98% of copper alloy grades
- Forms and bends easily — 95/100, better than 94% of copper alloy grades
Limitations
- Low strength — 105 MPa (15.2 ksi), worse than 85% of copper alloy grades
C68300 properties
Typical room-temperature values for C68300-O61; bars are the position among copper alloy grades.
Physical3
C68300 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 927°C (1,701 °F).
Mechanical13
C68300 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 55% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C68300 is rated for continuous service to 200°C (392 °F). It conducts heat at 133 W/m·K (76.8 BTU/hr·ft·°F), better than 71% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
C68300 conducts electricity at 30 % IACS, better than 71% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 64% of copper alloy grades.
Sustainability4
Producing a kilogram of C68300 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C68300's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (55/100); formability excellent (95/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C68300 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C68300
Is C68300 easy to machine?
Unleaded α-brass: gummy, long chips — use sharp positive-rake tools, high speed, light feeds; rating ≈30 % of free-cutting brass.
Can C68300 be welded?
Excellent for soldering and silver brazing; GTAW possible with Cu-Si or Cu-Sn filler but zinc fuming and porosity require ventilation and low heat input.
Can C68300 be formed, bent or molded?
Very good cold formability in O61/OS tempers — deep draws, tube bending and tubesheet expansion; anneal 425–600 °C between heavy operations and stress-relieve at ~275 °C to avoid SCC.
C68300 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 |
|---|---|---|
| Cuincluding trace Ag | 75 – 77.5 | 76 |
| Sbdezincification inhibitor | 0.02 – 0.1 | 0.05 |
| Siinhibitor / deoxidiser | 0.02 – 0.1 | 0.05 |
| Pb | ≤ 0.05 | |
| Fe | ≤ 0.06 | |
| Zn | balance |
What surface finishes work on C68300?
Polishes to a bright finish; accepts tin, nickel and chrome plating; use clear lacquer or chemical patina outdoors — anodizing not applicable.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does C68300 cost?
C68300 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C68300 — frequently asked
What is C68300 used for?
C68300 is typically used for condenser tubes, plumbing tube and marine tubing. In short: dezincification-resistant tube brass; formability rating 95; unleaded plumbing brass.
What is the yield strength of C68300?
C68300 has a typical yield strength of 105 MPa (15.2 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 85% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C68300 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Unleaded α-brass: gummy, long chips — use sharp positive-rake tools, high speed, light feeds; rating ≈30 % of free-cutting brass.
Can C68300 be welded?
Yes — weldability is rated good (55/100). Excellent for soldering and silver brazing; GTAW possible with Cu-Si or Cu-Sn filler but zinc fuming and porosity require ventilation and low heat input.
What surface finishes work on C68300?
Polishes to a bright finish; accepts tin, nickel and chrome plating; use clear lacquer or chemical patina outdoors — anodizing not applicable.
Can C68300 be formed, bent or molded?
Very good cold formability in O61/OS tempers — deep draws, tube bending and tubesheet expansion; anneal 425–600 °C between heavy operations and stress-relieve at ~275 °C to avoid SCC.
What is the maximum service temperature of C68300?
C68300 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C68300-O61 and C68300-H04?
O61 is the default condition — standard stocked soft condition for tube bending, expanding into tubesheets and deep drawing. H04: fully hard temper for springy flat parts and maximum strength with minimal forming. Yield strength is 105 MPa in O61 versus 410 MPa in H04.
How much does C68300 cost?
C68300 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- CDA Standard Designation & Alloy Data (C6xxxx wrought brasses) — Copper Development Association (2023)
- ASTM B135 / B111 — Seamless Brass and Copper-Alloy Condenser Tube — ASTM International (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Copper Alloys) — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.