Copper Alloy C51900 · supply condition
Copper Alloy C51900-H08
Properties of the H08 condition, compared with the other C51900 tempers.
Standard temper for connector springs, diaphragms and clips loaded in bending fatigue.
What is C51900-H08?
C51900-H08 is C51900 supplied in the H08 condition — standard temper for connector springs, diaphragms and clips loaded in bending fatigue. C51900-H08 has a yield strength of 630 MPa (91.4 ksi) and a tensile strength of 695 MPa (101 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 115 GPa (16.7 Msi). C51900-H08 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 910°C (1,670 °F). H02 is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- High strength — 630 MPa (91.4 ksi), better than 96% of copper alloy grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 100% of copper alloy grades
- Limited ductility — 5%, worse than 94% of copper alloy grades
- Difficult to machine — 25/100, worse than 85% of copper alloy grades
C51900-H08 properties
Typical room-temperature values for C51900-H08 — 8 properties are specific to this condition; the rest are grade-level values shared by every C51900 temper. Each bar shows where the value sits among the copper alloy grades in FabDigit's library — further right is higher.
Physical3
C51900-H08 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 910°C (1,670 °F).
Mechanical12
C51900-H08 has a yield strength of 630 MPa (91.4 ksi) and a tensile strength of 695 MPa (101 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C51900-H08 is rated for continuous service to 120°C (248 °F). It conducts heat at 67 W/m·K (38.7 BTU/hr·ft·°F), worse than 57% of copper alloy grades. Thermal expansion is 18.5 µm/m·K (10.3 µin/in·°F).
Electrical3
C51900-H08 conducts electricity at 15 % IACS, worse than 54% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C51900-H08 takes about 62 MJ of energy and emits 4.2 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C51900-H08's machinability is poor (25/100, worse than 85% of copper alloy grades); weldability fair (45/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other C51900 tempers and conditions
C51900 is also supplied in 9 other conditions. The full side-by-side table is on the C51900 overview.
- H02DefaultDefault stocked strip temper: balanced strength and bendability for contacts, clips and washers.450 MPa yield · 78 HRB
- H10Highest cold-rolled strength; use for flat springs bent only along the rolling direction.670 MPa yield · 97 HRB
- H08Standard temper for connector springs, diaphragms and clips loaded in bending fatigue.630 MPa yield · 95 HRB
- H04Pick for flat springs and contacts with only gentle bends, where higher elastic limit matters.530 MPa yield · 87 HRB
- O60Pick for deep drawing, severe forming or coining before final heat treatment.180 MPa yield · 95 HB
Working with C51900-H08
Is C51900 easy to machine?
Machinability only ~20 % of free-cutting brass — gummy, work-hardening chips; use sharp positive-rake tools, high speed, light feeds and flood coolant.
Can C51900 be welded?
Solder and braze excellently and resistance-weld well; oxyacetylene and TIG/MIG welding are poor because of tin oxide and hot-shortness, so avoid fusion joints in springs.
Can C51900 be formed, bent or molded?
Excellent cold formability in O60/H01; hard and spring tempers must be bent with the bend axis transverse to rolling and often need a 180–230 °C post-form stress relief to set the shape.
What surface finishes work on C51900?
Not anodizable; readily electroplated with tin, nickel, silver or gold after cyanide-free cleaning, and polishes to a bright bronze finish (bright-dip or lacquer to stop tarnish).
C51900 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 |
|---|---|---|
| Sn | 5 – 7 | 6 |
| Pdeoxidizer; raises strength | 0.03 – 0.35 | 0.2 |
| Zn | ≤ 0.3 | — |
| Fe | ≤ 0.1 | — |
| Pb | ≤ 0.05 | — |
| CuCu + named elements 99.5 % min | balance | — |
C51900-H08 — frequently asked
What is C51900-H08 used for?
C51900-H08 is typically used for springs & contacts, connectors and bushings. In short: spring-grade phosphor bronze.
What is the yield strength of C51900-H08?
C51900-H08 has a typical yield strength of 630 MPa (91.4 ksi) and a tensile strength of 695 MPa (101 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C51900-H08 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 85% of copper alloy grades). Machinability only ~20 % of free-cutting brass — gummy, work-hardening chips; use sharp positive-rake tools, high speed, light feeds and flood coolant.
Can C51900-H08 be welded?
With care — weldability is rated fair (45/100). Solder and braze excellently and resistance-weld well; oxyacetylene and TIG/MIG welding are poor because of tin oxide and hot-shortness, so avoid fusion joints in springs.
What surface finishes work on C51900-H08?
Not anodizable; readily electroplated with tin, nickel, silver or gold after cyanide-free cleaning, and polishes to a bright bronze finish (bright-dip or lacquer to stop tarnish).
Can C51900-H08 be formed, bent or molded?
Excellent cold formability in O60/H01; hard and spring tempers must be bent with the bend axis transverse to rolling and often need a 180–230 °C post-form stress relief to set the shape.
What is the maximum service temperature of C51900-H08?
C51900-H08 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C51900-H02 and C51900-O60?
H02 is the default condition — default stocked strip temper: balanced strength and bendability for contacts, clips and washers. O60: pick for deep drawing, severe forming or coining before final heat treatment. Yield strength is 450 MPa in H02 versus 180 MPa in O60.
Can FabDigit make parts in C51900-H08?
Yes — C51900-H08 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B103/B103M — Phosphor Bronze Plate, Sheet, Strip and Rolled Bar — ASTM International (2019)
- ASTM B139/B139M — Phosphor Bronze Rod, Bar and Shapes — ASTM International (2017)
- EN 1654 / EN 1652 — Copper and copper alloys, strip for springs and connectors (CuSn6, CW452K) — CEN (2019)
- GB/T 2059 / GB/T 2040 — (QSn6.5-0.1) — SAC (2017)
- C51900 alloy datasheet — Copper Development Association (copper.org) (2023)
- CuSn6 Werkstoff-Datenblatt — Deutsches Kupferinstitut (2005)
- ASM Handbook Vol. 2 — Properties of Nonferrous 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.