Copper Alloy C31600
UNS C31600
C31600 is a nickel-modified version of the leaded commercial bronze C31400, keeping the free-machining lead addition while raising strength and corrosion resistance.
Reference datasheet — C31600 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 H02 condition
C31600 tempers and conditions
C31600 is supplied in 7 conditions, soft to hard. H02 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
C31600 is a nickel-modified version of the leaded commercial bronze C31400, keeping the free-machining lead addition while raising strength and corrosion resistance. Default-temper values are 275 MPa yield, 350 MPa tensile, 20 % elongation, 95 HB, 38 % IACS and service to 200 °C, with a machinability score of 80; it is available as rod, bar and wire in O60, O61, H01–H06 and M30. As with all leaded coppers it cannot be fusion welded or hot worked, and lead smear limits mirror polishing. C31400 is the direct substitute when the nickel-related strength and corrosion gain is not needed. C31600 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). C31600 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 350 MPa (50.8 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 115 GPa (16.7 Msi).
What is C31600 used for?
- hardware fittings
- decorative fittings
- precision turned parts
Advantages
- Easy to machine — 80/100, better than 86% of copper alloy grades
- Forms and bends easily — 65/100, better than 78% of copper alloy grades
Limitations
- Difficult to weld — 20/100, worse than 88% of copper alloy grades
C31600 properties
Typical room-temperature values for C31600-H02; bars are the position among copper alloy grades.
Physical3
C31600 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 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 350 MPa (50.8 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C31600 is rated for continuous service to 200°C (392 °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 conducts electricity at 38 % 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 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's machinability is very good (80/100, better than 86% of copper alloy grades); weldability poor (20/100); formability good (65/100).
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. C31600 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C31600
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.
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 |
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.
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 C31600 cost?
C31600 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.
C31600 — frequently asked
What is C31600 used for?
C31600 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?
C31600 has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 350 MPa (50.8 ksi) — stronger than 57% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C31600 easy to machine?
Yes — machinability is rated very good (80/100, better than 86% 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 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?
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 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?
C31600 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 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.
How much does C31600 cost?
C31600 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
- 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; 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.