Copper Alloy CC755S-GM (Gravity die cast)
Finish state · default condition
EN CC755S
Default stock condition: best combination of surface finish, dimensional accuracy and strength for series water/valve fittings.
Values for the GM condition
Other CC755S tempers and conditions
CC755S is listed in 4 conditions; see the grade overview at CC755S.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Sand cast | Choose for larger, low-volume or one-off housings and valve bodies where thin-wall detail is not critical. | 135 | 355 | 22 | 90 HB | 23 % IACS |
GMDefaultThis page Gravity die cast | Default stock condition: best combination of surface finish, dimensional accuracy and strength for series water/valve fittings. | 150 | 370 | 22 | 95 HB | 24 % IACS |
Centrifugally cast | Choose for bushings, sleeves and rings needing dense, inclusion-free rotationally symmetric sections. | 155 | 385 | 22 | 100 HB | 24 % IACS |
Continuously cast | Choose for machined-from-bar parts: uniform fine structure, best soundness and consistent machining behaviour. | 155 | 385 | 20 | 100 HB | 25 % IACS |
What is CC755S-GM?
CC755S-GM is CC755S supplied in the GM condition — default stock condition: best combination of surface finish, dimensional accuracy and strength for series water/valve fittings. CC755S-GM has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 69% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 95 GPa (13.8 Msi). CC755S-GM has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 880°C (1,616 °F).
Advantages
- Low embodied carbon — 3.1 kg CO₂/kg, better than 95% of copper alloy grades
- Easy to machine — 78/100, better than 82% of copper alloy grades
Limitations
- Low stiffness — 95 GPa (13.8 Msi), worse than 93% of copper alloy grades
- Needs corrosion protection — 52/100, worse than 93% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
- Limited formability — 18/100, worse than 75% of copper alloy grades
CC755S-GM properties
Typical room-temperature values for CC755S-GM; 21 are specific to this condition. Other listed values are CC755S reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
CC755S-GM has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 880°C (1,616 °F).
Mechanical15
CC755S-GM has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 69% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 95 GPa (13.8 Msi).
Thermal6
CC755S-GM is rated for continuous service to 200°C (392 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), better than 58% of copper alloy grades. Thermal expansion is 21 µm/m·K (11.7 µin/in·°F).
Electrical3
CC755S-GM conducts electricity at 24 % IACS, better than 57% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 93% of copper alloy grades.
Sustainability4
Producing a kilogram of CC755S-GM takes about 50 MJ of energy and emits 3.1 kg of CO₂ — less than 89% of copper alloy grades. Typical recycled content is 75%.
Manufacturability8
CC755S-GM's machinability is very good (78/100, better than 82% of copper alloy grades); weldability poor (25/100); formability poor (18/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CC755S-GM
Is CC755S easy to machine?
Very free-machining with the 1 % Pb phase — use sharp positive-rake carbide or HSS, 0° to slight negative rake for brass, high speeds and light lubrication; expect short chips.
Can CC755S be welded?
Fusion welding is not recommended (Pb hot-cracking and Zn fuming); use brazing with silver filler, soldering or mechanical joining, and extract fumes.
Can CC755S be formed, bent or molded?
Casting alloy only — excellent fluidity for thin walls; boron refines grain and reduces gas porosity, degas the melt and use moderate pouring temperature (~1000–1050 °C).
What surface finishes work on CC755S?
Takes bright polishing, brushing, Ni/Cr or PVD plating and clear lacquer; do not anodize — for potable-water duty check lead-leaching regulations and consider a dezincification-resistant alternative.
CC755S 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 | 57 – 59 | 58 |
| Pbfree-machining phase | 0.5 – 1.5 | 1 |
| Alimproves fluidity and strength | 0.3 – 1 | 0.6 |
| Bgrain refiner / modifier — distinguishes CC755S from CuZn39Pb1Al-C | 0.01 – 0.06 | 0.02 |
| Fe | ≤ 0.8 | 0.3 |
| Sn | ≤ 0.5 | 0.2 |
| Ni | ≤ 1 | 0.2 |
| Mn | ≤ 0.5 | 0.1 |
| Si | ≤ 0.05 | — |
| Zn≈38–40 % | balance | — |
CC755S-GM — frequently asked
What is CC755S-GM used for?
CC755S-GM is typically used for precision fittings, hardware castings and valve parts. In short: boron grain-refined cast brass; thin-wall casting grade; very free-machining.
What is the yield strength of CC755S-GM?
CC755S-GM has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 69% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is CC755S-GM easy to machine?
Yes — machinability is rated very good (78/100, better than 82% of copper alloy grades). Very free-machining with the 1 % Pb phase — use sharp positive-rake carbide or HSS, 0° to slight negative rake for brass, high speeds and light lubrication; expect short chips.
Can CC755S-GM be welded?
Not readily — weldability is rated poor (25/100). Fusion welding is not recommended (Pb hot-cracking and Zn fuming); use brazing with silver filler, soldering or mechanical joining, and extract fumes.
What surface finishes work on CC755S-GM?
Takes bright polishing, brushing, Ni/Cr or PVD plating and clear lacquer; do not anodize — for potable-water duty check lead-leaching regulations and consider a dezincification-resistant alternative.
Can CC755S-GM be formed, bent or molded?
Casting alloy only — excellent fluidity for thin walls; boron refines grain and reduces gas porosity, degas the melt and use moderate pouring temperature (~1000–1050 °C).
What is the maximum service temperature of CC755S-GM?
CC755S-GM 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 CC755S-GM and CC755S-GS?
GM is the default condition — default stock condition: best combination of surface finish, dimensional accuracy and strength for series water/valve fittings. GS: choose for larger, low-volume or one-off housings and valve bodies where thin-wall detail is not critical. Yield strength is 150 MPa in GM versus 135 MPa in GS.
Sources
- EN 1982 — Copper and copper alloys: Ingots and castings — CEN (2017)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- CDA copper alloy datasheets (cast leaded brasses) — Copper Development Association (2023)
- European brass foundry alloy datasheets (CuZn39Pb1Al-C family) — various foundries (2022)
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.