Copper Alloy C69430
UNS C69430
C69430 is a lead-free copper-zinc-silicon brass in which silicon, rather than lead, provides strength and corrosion resistance, giving 515 MPa tensile, 240 MPa yield and 30 % elongation at 140 HB (80 HRB) in the default condition.
Reference datasheet — C69430 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 M30 condition
C69430 tempers and conditions
C69430 is supplied in 5 conditions, soft to hard. M30 is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Choose for maximum ductility before heavy cold forming, bending or upsetting. | 195 | 450 | 38 | 110 HB | 7 % IACS |
M30Default As hot extruded | Standard stocked condition for silicon-brass rod and forging stock; balanced strength and ductility. | 240 | 515 | 30 | 140 HB | — |
Extruded and drawn | Lightly drawn rod with better size tolerance and straightness than as-extruded, still readily machined and formed. | 310 | 585 | 25 | 155 HB | 6.5 % IACS |
Half hard | Pick where higher yield strength and cleaner machined finish are needed, e.g. valve stems and threaded fittings. | 345 | 620 | 22 | 170 HB | 6.6 % IACS |
Full hard | Maximum strength and wear resistance for stems, shafts and fasteners where little further forming is required. | 415 | 690 | 18 | 190 HB | 6.5 % IACS |
What is C69430?
C69430 is a lead-free copper-zinc-silicon brass in which silicon, rather than lead, provides strength and corrosion resistance, giving 515 MPa tensile, 240 MPa yield and 30 % elongation at 140 HB (80 HRB) in the default condition. Engineers specify it for weldable fittings and potable-water hardware, and it is on file as rod, bar and forging stock in O60, M30, H50, H02 and H04. Machinability rates about 40 against free-cutting brass, so expect roughly 30-40 % of C36000 productivity, and cold formability is only fair (score 45). Where machining volume dominates and welding is not required, leaded C69700 is the closer choice. C69430 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F). C69430 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 52% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 103 GPa (14.9 Msi).
What is C69430 used for?
- plumbing fittings
- weldable brass hardware
- decorative fittings
Advantages
- Readily welded — 75/100, better than 89% of copper alloy grades
- Ductile — tolerates forming and impact — 30%, better than 75% of copper alloy grades
Limitations
- Poor heat conductor — 28 W/m·K (16.2 BTU/hr·ft·°F), worse than 96% of copper alloy grades
- Low electrical conductivity — 6.7 % IACS, worse than 89% of copper alloy grades
C69430 properties
Typical room-temperature values for C69430-M30; bars are the position among copper alloy grades.
Physical3
C69430 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F).
Mechanical13
C69430 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 52% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C69430 is rated for continuous service to 200°C (392 °F). It conducts heat at 28 W/m·K (16.2 BTU/hr·ft·°F), worse than 96% of copper alloy grades. Thermal expansion is 20.2 µm/m·K (11.2 µin/in·°F).
Electrical3
C69430 conducts electricity at 6.7 % IACS, worse than 89% 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 C69430 takes about 58 MJ of energy and emits 3.8 kg of CO₂ — more than 61% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C69430's machinability is fair (40/100, better than 57% of copper alloy grades); weldability very good (75/100); formability fair (45/100).
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. C69430 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C69430
Is C69430 easy to machine?
Machines like a tough alpha brass, not a leaded one — use sharp positive-rake carbide, high speed, generous coolant and chip breakers; expect ~30–40 % of C36000 productivity.
Can C69430 be welded?
One of the few brasses that welds well: GTAW/GMAW with silicon-bronze (ERCuSi-A) filler, resistance and braze welding all practical with low zinc fuming.
Can C69430 be formed, bent or molded?
Excellent hot workability at 650–800 °C for extrusion and forging; cold bending and heading are only fair, so anneal between heavy operations.
C69430 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 |
|---|---|---|
| Cu | 80 – 83 | 81.5 |
| Si | 3.5 – 4.5 | 4 |
| Asdezincification inhibitor — distinguishes C69430 from C69400 | 0.03 – 0.06 | 0.05 |
| Pblow-lead / potable-water compliant | ≤ 0.09 | |
| Fe | ≤ 0.2 | |
| Znremainder, nominally ~15–16 % | balance |
What surface finishes work on C69430?
Polishes to a bright golden finish; accepts nickel, chrome and tin plating and benzotriazole/lacquer protection — no anodizing.
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).
How much does C69430 cost?
C69430 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.
C69430 — frequently asked
What is C69430 used for?
C69430 is typically used for plumbing fittings, weldable brass hardware and decorative fittings. In short: weldable silicon brass; lead-free plumbing alloy; high strength, fair machining.
What is the yield strength of C69430?
C69430 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 52% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is C69430 easy to machine?
Not especially — machinability is rated fair (40/100, better than 57% of copper alloy grades). Machines like a tough alpha brass, not a leaded one — use sharp positive-rake carbide, high speed, generous coolant and chip breakers; expect ~30–40 % of C36000 productivity.
Can C69430 be welded?
Yes — weldability is rated very good (75/100). One of the few brasses that welds well: GTAW/GMAW with silicon-bronze (ERCuSi-A) filler, resistance and braze welding all practical with low zinc fuming.
What surface finishes work on C69430?
Polishes to a bright golden finish; accepts nickel, chrome and tin plating and benzotriazole/lacquer protection — no anodizing.
Can C69430 be formed, bent or molded?
Excellent hot workability at 650–800 °C for extrusion and forging; cold bending and heading are only fair, so anneal between heavy operations.
What is the maximum service temperature of C69430?
C69430 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C69430-M30 and C69430-H04?
M30 is the default condition — standard stocked condition for silicon-brass rod and forging stock; balanced strength and ductility. H04: maximum strength and wear resistance for stems, shafts and fasteners where little further forming is required. Yield strength is 240 MPa in M30 versus 415 MPa in H04.
How much does C69430 cost?
C69430 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 B371/B371M — Copper-Zinc-Silicon Alloy Rod — ASTM International (2019)
- CDA/UNS Alloy Datasheet C69400 / C69430 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (copper alloys) — 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.