Copper Alloy C50700-H04
Supply condition
UNS C50700 · ASTM B103
H04 = full hard
Choose for wear surfaces, bushings and flat parts needing high strength with light forming only.
Values for the H04 condition
Other C50700 tempers and conditions
C50700 is listed in 9 conditions; see the grade overview at C50700.
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 |
H04This page 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-H04?
C50700-H04 is C50700 supplied in the H04 condition — choose for wear surfaces, bushings and flat parts needing high strength with light forming only. C50700-H04 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 475 MPa (68.9 ksi) — stronger than 83% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 117 GPa (17 Msi). C50700-H04 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). H08 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High strength — 425 MPa (61.6 ksi), better than 83% of copper alloy grades
Limitations
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Limited ductility — 7%, worse than 86% of copper alloy grades
C50700-H04 properties
Typical room-temperature values for C50700-H04; 21 are specific to this condition. Other listed values are C50700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C50700-H04 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-H04 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 475 MPa (68.9 ksi) — stronger than 83% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C50700-H04 is rated for continuous service to 175°C (347 °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-H04 conducts electricity at 31 % 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-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 35%.
Manufacturability7
C50700-H04's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability fair (35/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C50700-H04
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.
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.
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 | — |
C50700-H04 — frequently asked
What is C50700-H04 used for?
C50700-H04 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-H04?
C50700-H04 has a typical yield strength of 425 MPa (61.6 ksi) and a tensile strength of 475 MPa (68.9 ksi) — stronger than 83% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C50700-H04 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% 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-H04 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-H04?
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-H04 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-H04?
C50700-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 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.