Copper Alloy C47940
UNS C47940 · ASTM B124
C47940 is a leaded forging-grade naval brass covered by ASTM B124 for hot-pressed rod, bar and shapes.
Reference datasheet — C47940 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
C47940 tempers and conditions
C47940 is supplied in 6 conditions, soft to hard. M30 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Fully softened condition for maximum ductility in severe cold forming, heading or coining. | 140 | 380 | 48 | 85 HB | — |
Light annealed | Stress-relieved/light-annealed rod for parts that will be bent or upset and where SCC risk must be reduced. | 160 | 400 | 42 | 95 HB | — |
M30Default As hot extruded | Standard mill condition for forging stock and large-diameter rod; maximum ductility for subsequent hot forging. | 180 | 415 | 38 | 105 HB | 26 % IACS |
Extruded and drawn | Choose for straight, close-tolerance rod and hex with a modest strength gain over as-extruded. | 275 | 460 | 25 | 130 HB | — |
Half hard | Balanced strength and residual ductility for machined marine fittings and shafting. | 345 | 495 | 20 | 145 HB | — |
Full hard | Highest-strength rod condition for studs, pins and wear surfaces where forming is not needed. | 415 | 550 | 14 | 165 HB | — |
What is C47940?
C47940 is a leaded forging-grade naval brass covered by ASTM B124 for hot-pressed rod, bar and shapes. The small lead addition raises machinability to roughly 55 % of free-cutting brass while the α+β naval-brass base retains seawater corrosion resistance; typical values are 180 MPa yield, 415 MPa tensile, 38 % elongation, 105 HB (55 HRB), 26 % IACS and 200 °C maximum service temperature. It is not a fusion-welding alloy and cold formability is limited (score 50), so parts are hot forged near net shape and finish machined. C48200 machines faster; C46500 gives better dezincification resistance. C47940 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 885°C (1,625 °F). C47940 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 103 GPa (14.9 Msi).
What is C47940 used for?
- marine forgings
- valve and pump components
- fittings
Advantages
- Ductile — tolerates forming and impact — 38%, better than 82% of copper alloy grades
Limitations
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C47940 properties
Typical room-temperature values for C47940-M30; bars are the position among copper alloy grades.
Physical3
C47940 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 885°C (1,625 °F).
Mechanical14
C47940 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C47940 is rated for continuous service to 200°C (392 °F). It conducts heat at 116 W/m·K (67 BTU/hr·ft·°F), better than 64% of copper alloy grades. Thermal expansion is 20.9 µm/m·K (11.6 µin/in·°F).
Electrical3
C47940 conducts electricity at 26 % IACS, better than 63% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C47940 takes about 58 MJ of energy and emits 3.6 kg of CO₂ — more than 61% of copper alloy grades. Typical recycled content is 50%.
Manufacturability8
C47940's machinability is good (55/100, better than 71% of copper alloy grades); weldability poor (25/100); formability fair (50/100).
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. C47940 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C47940
Is C47940 easy to machine?
Machines well with sharp positive-rake tooling and flood coolant; the small Pb addition gives free-ish chips but expect stringier chips than C36000 — plan ~55–60 % of 1212 speeds.
Can C47940 be welded?
Not recommended for fusion welding (zinc fume, hot cracking, lead-induced cracking); join by soldering, silver brazing or mechanical fastening.
Can C47940 be formed, bent or molded?
Excellent hot forgeability at about 650–760 °C — its primary use; cold forming limited to annealed/light tempers, and cold-worked parts should be stress-relieved near 260–300 °C to avoid SCC.
C47940 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 |
|---|---|---|
| Cualpha-beta naval brass base | 63 – 66 | 64.5 |
| Sndezincification inhibitor | 0.2 – 1 | 0.6 |
| Pbmachinability aid | 0.1 – 1 | 0.5 |
| Fegrain refinement / strength | 0.1 – 1 | 0.4 |
| Nicorrosion resistance | 0.1 – 1 | 0.4 |
| Alimpurity limit | ≤ 0.1 | |
| Zn | balance |
What surface finishes work on C47940?
Polishes to a bright yellow finish; accepts nickel, chrome, tin or clear-lacquer/benzotriazole protection — anodizing does not apply to copper alloys.
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 C47940 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B124
How much does C47940 cost?
C47940 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.
C47940 — frequently asked
What is C47940 used for?
C47940 is typically used for marine forgings, valve and pump components and fittings. In short: forging-grade naval brass; free-machining marine forgings; near-net-shape hot press alloy.
What is the yield strength of C47940?
C47940 has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C47940 easy to machine?
Reasonably — machinability is rated good (55/100, better than 71% of copper alloy grades). Machines well with sharp positive-rake tooling and flood coolant; the small Pb addition gives free-ish chips but expect stringier chips than C36000 — plan ~55–60 % of 1212 speeds.
Can C47940 be welded?
Not readily — weldability is rated poor (25/100). Not recommended for fusion welding (zinc fume, hot cracking, lead-induced cracking); join by soldering, silver brazing or mechanical fastening.
What surface finishes work on C47940?
Polishes to a bright yellow finish; accepts nickel, chrome, tin or clear-lacquer/benzotriazole protection — anodizing does not apply to copper alloys.
Can C47940 be formed, bent or molded?
Excellent hot forgeability at about 650–760 °C — its primary use; cold forming limited to annealed/light tempers, and cold-worked parts should be stress-relieved near 260–300 °C to avoid SCC.
What is the maximum service temperature of C47940?
C47940 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 C47940-M30 and C47940-H04?
M30 is the default condition — standard mill condition for forging stock and large-diameter rod; maximum ductility for subsequent hot forging. H04: highest-strength rod condition for studs, pins and wear surfaces where forming is not needed. Yield strength is 180 MPa in M30 versus 415 MPa in H04.
How much does C47940 cost?
C47940 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 B124/B124M Copper and Copper Alloy Forging Rod, Bar and Shapes — ASTM International (2020)
- CDA/copper.org Alloy Database — wrought brass C47xxx group — 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; 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.