Copper Alloy C47940-M30
Temper · default condition
UNS C47940 · ASTM B124
M30 = as hot extruded
Standard mill condition for forging stock and large-diameter rod; maximum ductility for subsequent hot forging.
Values for the M30 condition
Other C47940 tempers and conditions
C47940 is listed in 6 conditions; see the grade overview at C47940.
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 | — |
M30DefaultThis page 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-M30?
C47940-M30 is C47940 in the M30 temper — standard mill condition for forging stock and large-diameter rod; maximum ductility for subsequent hot forging. C47940-M30 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). C47940-M30 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).
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-M30 properties
Typical room-temperature values for C47940-M30; 14 are specific to this condition. Other listed values are C47940 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C47940-M30 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-M30 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-M30 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-M30 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-M30 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-M30'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. Confirm any required mill or lot documentation when quoting.
Working with C47940-M30
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.
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.
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 | — |
C47940-M30 — frequently asked
What is C47940-M30 used for?
C47940-M30 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-M30?
C47940-M30 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-M30 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-M30 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-M30?
Polishes to a bright yellow finish; accepts nickel, chrome, tin or clear-lacquer/benzotriazole protection — anodizing does not apply to copper alloys.
Can C47940-M30 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-M30?
C47940-M30 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.