Copper Alloy C65400
UNS C65400 · ASTM B98
C65400 is a manganese-silicon bronze in the wrought silicon bronze family, offering higher strength than standard low-silicon grades and supplied to ASTM B98 as strip, wire and rod from O61 through H14.
Reference datasheet — C65400 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 H04 condition
C65400 tempers and conditions
C65400 is supplied in 9 conditions, soft to hard. H04 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 |
|---|---|---|---|---|---|---|
Annealed | Pick for deep drawing, severe forming or as the starting stock for subsequent cold work. | 205 | 455 | 40 | 62 HRB | — |
Quarter hard | Pick when moderate strength must be combined with substantial remaining bendability. | 415 | 505 | 20 | 140 HB | 7 % IACS |
Half hard | General-purpose strip/rod temper balancing strength with 90° bend capability. | 525 | 585 | 10 | 88 HRB | — |
Three-quarter hard | Pick for structural parts and fasteners needing high strength with light forming only. | 570 | 620 | 8 | 11 HRC | 6.5 % IACS |
H04Default Full hard | Most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. | 620 | 660 | 5 | 93 HRB | — |
Extra hard | Pick for flat springs and clips where forming is limited to gentle radii in the good bend direction. | 690 | 720 | 4 | 18 HRC | 6 % IACS |
Spring hard | Standard spring temper for contacts, washers and retaining components with high elastic limit. | 725 | 760 | 3 | 19 HRC | 5.9 % IACS |
Extra spring hard | Pick when spring rate and elastic limit must exceed H08 and only flat or very gently formed parts are made. | 760 | 790 | 3 | 20 HRC | 5.8 % IACS |
Strain hardened, half hard | Highest strength condition offered — flat spring strip and wire where no appreciable forming is required. | 795 | 830 | 2 | 21 HRC | 5.7 % IACS |
What is C65400?
C65400 is a manganese-silicon bronze in the wrought silicon bronze family, offering higher strength than standard low-silicon grades and supplied to ASTM B98 as strip, wire and rod from O61 through H14. It is used for structural fasteners and valve components that need 620 MPa yield, 660 MPa tensile and 93 HRB together with good corrosion resistance in marine environments. Elongation is only 5%, formability is rated 30 and service is limited to about 175 °C, so severe cold forming requires interstage annealing. C65100 is the alternative when ductility and cold heading matter more than strength. C65400 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F). C65400 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi).
What is C65400 used for?
- valve stems
- structural fasteners
- marine hardware
Advantages
- High strength — 620 MPa (89.9 ksi), better than 95% of copper alloy grades
- Readily welded — 80/100, better than 93% of copper alloy grades
- Good corrosion resistance — 76/100, better than 91% of copper alloy grades
Limitations
- Limited ductility — 5%, worse than 93% of copper alloy grades
- Low electrical conductivity — 6 % IACS, worse than 93% of copper alloy grades
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Poor heat conductor — 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 86% of copper alloy grades
C65400 properties
Typical room-temperature values for C65400-H04; bars are the position among copper alloy grades.
Physical3
C65400 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F).
Mechanical12
C65400 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C65400 is rated for continuous service to 175°C (347 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 86% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C65400 conducts electricity at 6 % IACS, worse than 93% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (76/100), better than 91% of copper alloy grades.
Sustainability4
Producing a kilogram of C65400 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%.
Manufacturability8
C65400's machinability is poor (33/100, worse than 53% of copper alloy grades); weldability very good (80/100); formability poor (30/100).
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. C65400 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C65400
Is C65400 easy to machine?
Gummy, stringy chips — use sharp positive-rake tools, high speed with light feed and generous coolant; rating ~30 % of AISI 1212, so allow extra tool life budget vs free-cutting brass.
Can C65400 be welded?
Excellent with GTAW/GMAW using ERCuSi-A filler and low interpass temperature; resistance and oxyacetylene welding are usable, but keep heat input low to limit silicide segregation.
Can C65400 be formed, bent or molded?
Very high work-hardening rate — form in O61/H01 with interstage anneals near 500–600 °C; hard and spring tempers should be bent with the grain and generous radii.
C65400 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 |
|---|---|---|
| Si | 2.7 – 3.4 | 3 |
| Sn | 1.5 – 2 | 1.8 |
| Cr | 0.01 – 0.12 | 0.05 |
| Zn | ≤ 0.5 | |
| Pbimpurity limit | ≤ 0.05 | |
| CuCu + Ag remainder | balance |
What surface finishes work on C65400?
Takes a bright mechanical polish and chemical patination; no anodizing — plate with Ni, Sn or Ag over a suitable strike, and avoid ammonia-containing cleaners on cold-worked parts.
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 C65400 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B98
How much does C65400 cost?
C65400 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.
C65400 — frequently asked
What is C65400 used for?
C65400 is typically used for valve stems, structural fasteners and marine hardware. In short: high-strength silicon bronze; 620 MPa yield in bronze; weldable structural fastener alloy.
What is the yield strength of C65400?
C65400 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C65400 easy to machine?
Not especially — machinability is rated poor (33/100, worse than 53% of copper alloy grades). Gummy, stringy chips — use sharp positive-rake tools, high speed with light feed and generous coolant; rating ~30 % of AISI 1212, so allow extra tool life budget vs free-cutting brass.
Can C65400 be welded?
Yes — weldability is rated very good (80/100). Excellent with GTAW/GMAW using ERCuSi-A filler and low interpass temperature; resistance and oxyacetylene welding are usable, but keep heat input low to limit silicide segregation.
What surface finishes work on C65400?
Takes a bright mechanical polish and chemical patination; no anodizing — plate with Ni, Sn or Ag over a suitable strike, and avoid ammonia-containing cleaners on cold-worked parts.
Can C65400 be formed, bent or molded?
Very high work-hardening rate — form in O61/H01 with interstage anneals near 500–600 °C; hard and spring tempers should be bent with the grain and generous radii.
What is the maximum service temperature of C65400?
C65400 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 C65400-H04 and C65400-O61?
H04 is the default condition — most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. O61: pick for deep drawing, severe forming or as the starting stock for subsequent cold work. Yield strength is 620 MPa in H04 versus 205 MPa in O61.
How much does C65400 cost?
C65400 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 B98/B98M — Copper-Silicon Alloy Rod, Bar and Shapes — ASTM International (2020)
- CDA Alloy Datasheet C65400 (Standards & Properties) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
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.