Copper Alloy C50700
UNS C50700 · ASTM B103
C50700 is a higher-tin wrought phosphor bronze to ASTM B103, supplied in O60, H01-H10, HR02 and HR08 tempers for spring and wear applications.
Reference datasheet — C50700 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 H08 condition
C50700 tempers and conditions
C50700 is supplied in 9 conditions, soft to hard. H08 is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for deep drawing, severe forming or coining before a final age/stress-relief. | 105 | 290 | 48 | 65 HB | 34 % IACS |
Quarter hard | Use when moderate strength must be combined with continued bending/forming. | 270 | 350 | 25 | 103 HB | 32 % IACS |
Half hard | General-purpose stocked temper for stamped contacts, washers and bushings. | 340 | 405 | 14 | 120 HB | 31 % IACS |
Half hard, cold worked and stress-relieved | Pick when formed parts need improved elastic limit and reduced stress-relaxation/SCC risk after stamping. | 385 | 430 | 12 | 130 HB | 32 % IACS |
Full hard | Choose for wear surfaces, bushings and flat parts needing high strength with light forming only. | 425 | 475 | 7 | 145 HB | 31 % IACS |
Extra hard | Intermediate step between hard and spring temper for stiff flat springs. | 475 | 520 | 5 | 158 HB | 30 % IACS |
H08Default Spring hard | Standard stocked spring temper for connector contacts, clips and flat springs; stress-relieve after forming. | 505 | 550 | 4 | 170 HB | 30 % IACS |
Spring temper, stress-relieved | Best combination of elastic limit and low stress relaxation for long-life electrical contact springs. | 530 | 570 | 4 | 175 HB | 32 % IACS |
Extra spring hard | Highest strength strip temper — for very high contact force springs with minimal bending. | 540 | 585 | 3 | 185 HB | 30 % IACS |
What is C50700?
C50700 is a higher-tin wrought phosphor bronze to ASTM B103, supplied in O60, H01-H10, HR02 and HR08 tempers for spring and wear applications. The default condition reaches 550 MPa tensile, 505 MPa yield, 170 HB (88 HRB) and 4 % elongation, with service to 150 °C, which suits heavy springs, bushings and bearing strip. The trade-offs are limited cold formability (score 35), poor to fair fusion weldability and machinability around 20 % of free-cutting brass. Where deep forming rather than spring force governs, drop back to C50200 or C50500. C50700 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,025°C (1,877 °F). C50700 has a yield strength of 505 MPa (73.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
What is C50700 used for?
- heavy springs
- bushings
- bearing bronze strip
- diaphragms
Advantages
- High strength — 505 MPa (73.2 ksi), better than 90% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
C50700 properties
Typical room-temperature values for C50700-H08; bars are the position among copper alloy grades.
Physical3
C50700 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,025°C (1,877 °F).
Mechanical15
C50700 has a yield strength of 505 MPa (73.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C50700 is rated for continuous service to 150°C (302 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), better than 71% of copper alloy grades. Thermal expansion is 17.8 µm/m·K (9.89 µin/in·°F).
Electrical3
C50700 conducts electricity at 30 % IACS, better than 71% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 58% of copper alloy grades.
Sustainability4
Producing a kilogram of C50700 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 35%.
Manufacturability7
C50700's machinability is fair (35/100, better than 51% of copper alloy grades); weldability fair (35/100); formability fair (35/100).
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. C50700 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C50700
Is C50700 easy to machine?
Machines like other low-lead phosphor bronzes — gummy, long chips; use sharp positive-rake carbide, high speed, generous coolant; rating ≈20% of free-cutting brass.
Can C50700 be welded?
Fusion welding is poor to fair (hot-short, P loss); prefer resistance spot/seam welding, soldering or silver brazing with low heat input.
Can C50700 be formed, bent or molded?
Excellent cold formability in O60/H01; in spring tempers keep bend radii ≥2t and bend with grain, then stress-relieve 175–230 °C to restore elastic limit.
C50700 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 |
|---|---|---|
| Snsolid-solution strengthener | 1.5 – 2 | 1.8 |
| Pdeoxidizer, raises strength and wear resistance | 0.1 – 0.35 | 0.2 |
| Fe | ≤ 0.1 | |
| Pb | ≤ 0.05 | |
| Zn | ≤ 0.3 | |
| CuCu + named elements 99.5 min (Ag countable as Cu) | balance |
What surface finishes work on C50700?
Takes bright polishing and tin, silver or nickel plating well; not anodizable — protect from tarnish with benzotriazole or lacquer, and avoid ammonia exposure on hard tempers.
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).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C50700 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B103
How much does C50700 cost?
C50700 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.
C50700 — frequently asked
What is C50700 used for?
C50700 is typically used for heavy springs, bushings, bearing bronze strip and diaphragms. In short: strongest phosphor bronze here; spring and bearing temper; wear-resistant strip stock.
What is the yield strength of C50700?
C50700 has a typical yield strength of 505 MPa (73.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C50700 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Machines like other low-lead phosphor bronzes — gummy, long chips; use sharp positive-rake carbide, high speed, generous coolant; rating ≈20% of free-cutting brass.
Can C50700 be welded?
With care — weldability is rated fair (35/100). Fusion welding is poor to fair (hot-short, P loss); prefer resistance spot/seam welding, soldering or silver brazing with low heat input.
What surface finishes work on C50700?
Takes bright polishing and tin, silver or nickel plating well; not anodizable — protect from tarnish with benzotriazole or lacquer, and avoid ammonia exposure on hard tempers.
Can C50700 be formed, bent or molded?
Excellent cold formability in O60/H01; in spring tempers keep bend radii ≥2t and bend with grain, then stress-relieve 175–230 °C to restore elastic limit.
What is the maximum service temperature of C50700?
C50700 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 C50700-H08 and C50700-O60?
H08 is the default condition — standard stocked spring temper for connector contacts, clips and flat springs; stress-relieve after forming. O60: pick for deep drawing, severe forming or coining before a final age/stress-relief. Yield strength is 505 MPa in H08 versus 105 MPa in O60.
How much does C50700 cost?
C50700 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 B103/B103M — Phosphor Bronze Plate, Sheet, Strip and Rolled Bar — ASTM International (2019)
- CDA/UNS alloy data sheet, C50700 phosphor bronze — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Copper and Copper Alloys) — ASM International (1990)
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.