Copper Alloy C68400-H04
Supply condition
UNS C68400
H04 = full hard
Pick for maximum strength and wear resistance in shafts, valve stems and bushings with little further forming.
Values for the H04 condition
Other C68400 tempers and conditions
C68400 is listed in 9 conditions; see the grade overview at C68400.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick when maximum ductility for bending, spinning or deep drawing is needed before final forming. | 200 | 460 | 32 | 100 HB | 15 % IACS |
As hot rolled | Pick for hot-rolled plate/flats where strength requirements are modest and further machining follows. | 230 | 480 | 28 | 115 HB | 15 % IACS |
As hot extruded | Standard condition for large-diameter rod, hollows and shapes; best hot-worked ductility, lowest cold-work stresses. | 250 | 500 | 26 | 120 HB | 15 % IACS |
Quarter hard | Light cold draw for straight, close-tolerance rod that still needs to be bent or headed. | 290 | 530 | 24 | 135 HB | 14.5 % IACS |
Light drawn | Light-drawn tube temper for hollow marine fittings that still need bending or expanding. | 300 | 540 | 22 | 140 HB | 15 % IACS |
H02Default Half hard | Default stocked rod/bar temper — best balance of strength, straightness and machinability for marine hardware and fasteners. | 340 | 570 | 20 | 150 HB | 14.5 % IACS |
Cold drawn and stress relieved | Choose when residual stresses must be lowered to resist stress-corrosion cracking in ammonia or marine service. | 350 | 560 | 20 | 150 HB | 15 % IACS |
H04This page Full hard | Pick for maximum strength and wear resistance in shafts, valve stems and bushings with little further forming. | 450 | 650 | 12 | 180 HB | 14 % IACS |
Extra hard | Heavily drawn small-diameter rod/wire for springy or high-load fastener applications; very limited ductility. | 540 | 720 | 8 | 200 HB | 14 % IACS |
What is C68400-H04?
C68400-H04 is C68400 supplied in the H04 condition — pick for maximum strength and wear resistance in shafts, valve stems and bushings with little further forming. C68400-H04 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 86% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 103 GPa (14.9 Msi). C68400-H04 has a density of 8.35 g/cm³ (0.302 lb/in³), lighter than 77% of copper alloy grades. It melts at 865°C (1,589 °F). H02 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High strength — 450 MPa (65.3 ksi), better than 86% of copper alloy grades
Limitations
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Poor heat conductor — 44 W/m·K (25.4 BTU/hr·ft·°F), worse than 78% of copper alloy grades
C68400-H04 properties
Typical room-temperature values for C68400-H04; 20 are specific to this condition. Other listed values are C68400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C68400-H04 has a density of 8.35 g/cm³ (0.302 lb/in³), lighter than 77% of copper alloy grades. It melts at 865°C (1,589 °F).
Mechanical14
C68400-H04 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 86% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C68400-H04 is rated for continuous service to 175°C (347 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), worse than 78% of copper alloy grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
C68400-H04 conducts electricity at 14 % IACS, worse than 56% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C68400-H04 takes about 50 MJ of energy and emits 3.4 kg of CO₂ — less than 89% of copper alloy grades. Typical recycled content is 50%.
Manufacturability8
C68400-H04's machinability is fair (38/100, better than 55% of copper alloy grades); weldability fair (40/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68400-H04
Is C68400 easy to machine?
Machines like unleaded high-strength brass (~30 % of AISI 1212): use sharp, positive-rake carbide, high speed with light feeds, and copious coolant to avoid gummy chips and built-up edge.
Can C68400 be welded?
Fusion welding is restricted by zinc fuming and porosity; prefer brazing, silver soldering or GTAW with silicon-bronze filler, low heat input and good extraction.
Can C68400 be formed, bent or molded?
Best hot worked at ~650–750 °C (extrusion, forging); cold formability is limited by the hard silicide phase, so allow interanneals at ~500–600 °C between draws.
What surface finishes work on C68400?
Polishes and buffs well and takes Ni/Cr or decorative electroplate readily; anodizing is not applicable — protect with clear lacquer or chemical patina, and stress-relieve before service in ammonia-bearing atmospheres.
C68400 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 |
|---|---|---|
| CuCu-Zn α+β matrix; exact registry limits should be confirmed against the governing standard | 55 – 60 | 57.5 |
| Siforms hard Cu-Zn-Si silicide phase for strength/wear | 0.5 – 1.5 | 1 |
| Mnsolid-solution and Mn-Si intermetallic strengthening | 1.5 – 3 | 2 |
| Fegrain refiner / impurity limit | ≤ 0.5 | 0.2 |
| Al | ≤ 0.5 | 0.2 |
| Sn | ≤ 0.5 | — |
| Pbkept low; not a free-cutting grade | ≤ 0.2 | — |
| Zn | balance | — |
C68400-H04 — frequently asked
What is C68400-H04 used for?
C68400-H04 is typically used for marine hardware, heavy-duty fasteners and structural components. In short: high-strength silicon brass; marine fastener grade; limited cold formability.
What is the yield strength of C68400-H04?
C68400-H04 has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 86% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C68400-H04 easy to machine?
Not especially — machinability is rated fair (38/100, better than 55% of copper alloy grades). Machines like unleaded high-strength brass (~30 % of AISI 1212): use sharp, positive-rake carbide, high speed with light feeds, and copious coolant to avoid gummy chips and built-up edge.
Can C68400-H04 be welded?
With care — weldability is rated fair (40/100). Fusion welding is restricted by zinc fuming and porosity; prefer brazing, silver soldering or GTAW with silicon-bronze filler, low heat input and good extraction.
What surface finishes work on C68400-H04?
Polishes and buffs well and takes Ni/Cr or decorative electroplate readily; anodizing is not applicable — protect with clear lacquer or chemical patina, and stress-relieve before service in ammonia-bearing atmospheres.
Can C68400-H04 be formed, bent or molded?
Best hot worked at ~650–750 °C (extrusion, forging); cold formability is limited by the hard silicide phase, so allow interanneals at ~500–600 °C between draws.
What is the maximum service temperature of C68400-H04?
C68400-H04 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C68400-H02 and C68400-H06?
H02 is the default condition — default stocked rod/bar temper — best balance of strength, straightness and machinability for marine hardware and fasteners. H06: heavily drawn small-diameter rod/wire for springy or high-load fastener applications; very limited ductility. Yield strength is 340 MPa in H02 versus 540 MPa in H06.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (wrought brass section) — ASM International (1990)
- ASTM B36/B124/B927 — wrought brass rod, bar, shapes and temper designations (ASTM B601) — ASTM International (2020)
- CDA/UNS copper alloy designation listings (C6xxxx high-strength brasses) — Copper Development Association (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.