Copper Alloy C51900-H06
Supply condition
UNS C51900 · EN CuSn6, CW452K
H06 = extra hard
Pick where near-spring strength is needed but full spring temper is too brittle to form.
Values for the H06 condition
Other C51900 tempers and conditions
C51900 is listed in 10 conditions; see the grade overview at C51900.
Compare all 10 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 final heat treatment. | 180 | 380 | 60 | 95 HB | — |
Quarter hard | Pick when moderate bending or forming is still needed but higher strength than annealed is wanted. | 340 | 450 | 35 | 128 HB | 15 % IACS |
Light-drawn wire/rod | Pick for wire and small rod that must still be coiled or headed after drawing. | 400 | 500 | 22 | 150 HB | 15 % IACS |
H02Default Half hard | Default stocked strip temper: balanced strength and bendability for contacts, clips and washers. | 450 | 520 | 20 | 155 HB | 15 % IACS |
Full hard | Pick for flat springs and contacts with only gentle bends, where higher elastic limit matters. | 530 | 600 | 10 | 175 HB | 14.5 % IACS |
H06This page Extra hard | Pick where near-spring strength is needed but full spring temper is too brittle to form. | 590 | 655 | 7 | 193 HB | 14 % IACS |
Spring hard | Standard temper for connector springs, diaphragms and clips loaded in bending fatigue. | 630 | 695 | 5 | 200 HB | 14 % IACS |
Extra spring hard | Highest cold-rolled strength; use for flat springs bent only along the rolling direction. | 670 | 730 | 3 | 210 HB | 14 % IACS |
spring temper, stress-relieved (low-temperature bake) | Pick for formed springs that must hold load: a 180–230 °C bake raises the elastic limit and cuts stress relaxation. | 670 | 710 | 5 | 19 HRC | 14 % IACS |
Hard drawn | Pick for helical compression/extension springs and woven mesh needing maximum wire strength. | 690 | 760 | 4 | 218 HB | 14 % IACS |
What is C51900-H06?
C51900-H06 is C51900 supplied in the H06 condition — pick where near-spring strength is needed but full spring temper is too brittle to form. C51900-H06 has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 94% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 115 GPa (16.7 Msi). C51900-H06 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; H06 is available on request or by drawing note.
Advantages
- High strength — 590 MPa (85.6 ksi), better than 94% of copper alloy grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Limited ductility — 7%, worse than 86% of copper alloy grades
C51900-H06 properties
Typical room-temperature values for C51900-H06; 20 are specific to this condition. Other listed values are C51900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C51900-H06 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).
Mechanical14
C51900-H06 has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 94% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C51900-H06 is rated for continuous service to 150°C (302 °F). It conducts heat at 67 W/m·K (38.7 BTU/hr·ft·°F), worse than 56% of copper alloy grades. Thermal expansion is 18.5 µm/m·K (10.3 µin/in·°F).
Electrical3
C51900-H06 conducts electricity at 14 % IACS, worse than 56% 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-H06 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-H06's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (40/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C51900-H06
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-H06 — frequently asked
What is C51900-H06 used for?
C51900-H06 is typically used for springs & contacts, connectors and bushings. In short: spring-grade phosphor bronze.
What is the yield strength of C51900-H06?
C51900-H06 has a typical yield strength of 590 MPa (85.6 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 94% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C51900-H06 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% 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-H06 be welded?
With care — weldability is rated fair (40/100). 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-H06?
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-H06 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-H06?
C51900-H06 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 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-H06?
Yes — C51900-H06 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. 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.