Copper Alloy C68300-H04
Supply condition
UNS C68300
H04 = full hard
Fully hard temper for springy flat parts and maximum strength with minimal forming.
Values for the H04 condition
Other C68300 tempers and conditions
C68300 is listed in 11 conditions; see the grade overview at C68300.
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 |
H04This page 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-H04?
C68300-H04 is C68300 supplied in the H04 condition — fully hard temper for springy flat parts and maximum strength with minimal forming. C68300-H04 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 81% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 110 GPa (16 Msi). C68300-H04 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). O61 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High strength — 410 MPa (59.5 ksi), better than 81% of copper alloy grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Limited ductility — 8%, worse than 83% of copper alloy grades
C68300-H04 properties
Typical room-temperature values for C68300-H04; 20 are specific to this condition. Other listed values are C68300 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C68300-H04 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-H04 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 81% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C68300-H04 is rated for continuous service to 150°C (302 °F). It conducts heat at 129 W/m·K (74.5 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-H04 conducts electricity at 29 % IACS, better than 71% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (64/100), better than 52% of copper alloy grades.
Sustainability4
Producing a kilogram of C68300-H04 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-H04's machinability is fair (40/100, better than 57% of copper alloy grades); weldability fair (52/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68300-H04
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.
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.
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 | — |
C68300-H04 — frequently asked
What is C68300-H04 used for?
C68300-H04 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-H04?
C68300-H04 has a typical yield strength of 410 MPa (59.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 81% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C68300-H04 easy to machine?
Not especially — machinability is rated fair (40/100, better than 57% 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-H04 be welded?
With care — weldability is rated fair (52/100). 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-H04?
Polishes to a bright finish; accepts tin, nickel and chrome plating; use clear lacquer or chemical patina outdoors — anodizing not applicable.
Can C68300-H04 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-H04?
C68300-H04 is rated for continuous use to about 150°C (302 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.