Copper Alloy C31600-H04
Supply condition
UNS C31600
H04 = full hard
Choose for maximum strength and stiffness of threaded fasteners, studs and contact pins where little forming follows.
Values for the H04 condition
Other C31600 tempers and conditions
C31600 is listed in 7 conditions; see the grade overview at C31600.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for maximum ductility: heading, staking, riveting, severe bending or deep upsetting of rod. | 95 | 280 | 45 | 55 HB | 40 % IACS |
As hot extruded | Economical condition for large sections and shapes that will be fully machined; lowest strength, no residual drawing stress. | 110 | 290 | 40 | 60 HB | 38 % IACS |
Annealed | Intermediate anneal for rod/section that still needs moderate cold forming with slightly higher strength than O60. | 125 | 300 | 40 | 65 HB | 38 % IACS |
Quarter hard | Use when bending or moderate forming must be combined with better straightness and strength than annealed rod. | 205 | 315 | 30 | 78 HB | 38 % IACS |
H02Default Half hard | Standard stock condition for screw-machine rod and electrical hardware: best balance of strength, chip control and residual formability. | 275 | 350 | 20 | 95 HB | 38 % IACS |
H04This page Full hard | Choose for maximum strength and stiffness of threaded fasteners, studs and contact pins where little forming follows. | 345 | 415 | 10 | 112 HB | 37 % IACS |
Extra hard | Small-diameter wire/rod where peak hardness and spring-back are wanted and ductility is not required. | 400 | 450 | 6 | 122 HB | 37 % IACS |
What is C31600-H04?
C31600-H04 is C31600 supplied in the H04 condition — choose for maximum strength and stiffness of threaded fasteners, studs and contact pins where little forming follows. C31600-H04 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 115 GPa (16.7 Msi). C31600-H04 has a density of 8.78 g/cm³ (0.317 lb/in³), heavier than 53% of copper alloy grades. It melts at 1,004°C (1,839 °F). H02 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- Easy to machine — 82/100, better than 90% of copper alloy grades
Limitations
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Difficult to weld — 20/100, worse than 88% of copper alloy grades
- Limited ductility — 10%, worse than 76% of copper alloy grades
C31600-H04 properties
Typical room-temperature values for C31600-H04; 11 are specific to this condition. Other listed values are C31600 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C31600-H04 has a density of 8.78 g/cm³ (0.317 lb/in³), heavier than 53% of copper alloy grades. It melts at 1,004°C (1,839 °F).
Mechanical11
C31600-H04 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C31600-H04 is rated for continuous service to 175°C (347 °F). It conducts heat at 145 W/m·K (83.8 BTU/hr·ft·°F), better than 72% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C31600-H04 conducts electricity at 37 % IACS, better than 73% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 68% of copper alloy grades.
Sustainability4
Producing a kilogram of C31600-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%.
Manufacturability7
C31600-H04's machinability is very good (82/100, better than 90% of copper alloy grades); weldability poor (20/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C31600-H04
Is C31600 easy to machine?
Excellent free-cutting behaviour (~80 % of C36000): use positive-rake carbide or HSS, high speed, light feed and flood coolant; lead gives short chips and fine threads.
Can C31600 be welded?
Do not fusion weld — lead causes hot cracking; join by soft soldering (excellent), silver brazing with care, or mechanical/crimped joints.
Can C31600 be formed, bent or molded?
Cold form in O60/H01 (heading, riveting, moderate bends); hot working is not recommended because of lead-induced hot shortness.
What surface finishes work on C31600?
Buffs to a bright bronze color but lead smear limits mirror polish; tin, nickel or gold plate for contacts and use benzotriazole/lacquer to control tarnish.
C31600 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 + sum of named elements ≥ 99.5 % | 87.5 – 90.5 | 89 |
| Pbfree-machining phase | 1.3 – 2.5 | 1.9 |
| NiNi + Co counted together | 0.7 – 1.2 | 1 |
| Pwith Ni forms strengthening phosphide | 0.04 – 0.1 | 0.06 |
| Fe | ≤ 0.1 | — |
| Znremainder, nominally ~8–9 % | balance | — |
C31600-H04 — frequently asked
What is C31600-H04 used for?
C31600-H04 is typically used for hardware fittings, decorative fittings and precision turned parts. In short: nickel-strengthened leaded bronze; free-cutting, score 80; better corrosion than C31400.
What is the yield strength of C31600-H04?
C31600-H04 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 73% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C31600-H04 easy to machine?
Yes — machinability is rated very good (82/100, better than 90% of copper alloy grades). Excellent free-cutting behaviour (~80 % of C36000): use positive-rake carbide or HSS, high speed, light feed and flood coolant; lead gives short chips and fine threads.
Can C31600-H04 be welded?
Not readily — weldability is rated poor (20/100). Do not fusion weld — lead causes hot cracking; join by soft soldering (excellent), silver brazing with care, or mechanical/crimped joints.
What surface finishes work on C31600-H04?
Buffs to a bright bronze color but lead smear limits mirror polish; tin, nickel or gold plate for contacts and use benzotriazole/lacquer to control tarnish.
Can C31600-H04 be formed, bent or molded?
Cold form in O60/H01 (heading, riveting, moderate bends); hot working is not recommended because of lead-induced hot shortness.
What is the maximum service temperature of C31600-H04?
C31600-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 C31600-H02 and C31600-O60?
H02 is the default condition — standard stock condition for screw-machine rod and electrical hardware: best balance of strength, chip control and residual formability. O60: pick for maximum ductility: heading, staking, riveting, severe bending or deep upsetting of rod. Yield strength is 275 MPa in H02 versus 95 MPa in O60.
Sources
- ASTM B140/B140M — Copper-Zinc-Lead (Leaded Red Brass / Hardware Bronze) Rod, Bar and Shapes — ASTM International (2019)
- Copper Alloy C31600 alloy data (UNS registration) — Copper Development Association / copper.org (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASTM B301/B301M — Free-Cutting Copper Rod, Bar, Wire and Shapes — ASTM International (2018)
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.