Copper Alloy CC750S-GM
Finish state
EN CC750S
GM = permanent (metal) mould cast, gravity die
Pick for higher-volume small parts needing better surface, tighter tolerance and ~20 % higher strength from the finer chill structure.
Values for the GM condition
Other CC750S tempers and conditions
CC750S is listed in 4 conditions; see the grade overview at CC750S.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
GSDefault Sand cast | Default condition for general hardware, decorative and low-pressure fittings poured in sand or shell moulds. | 90 | 210 | 18 | 55 HB | 26 % IACS |
Continuously cast bar / tube | Best when the part will be fully machined from stock: continuous-cast bar and hollow give uniform, sound structure with free-cutting behaviour. | 105 | 240 | 16 | 62 HB | 26 % IACS |
GMThis page Permanent (metal) mould cast, gravity die | Pick for higher-volume small parts needing better surface, tighter tolerance and ~20 % higher strength from the finer chill structure. | 110 | 250 | 15 | 65 HB | 26 % IACS |
Centrifugally cast | Choose for rings, bushings and sleeve blanks where centrifugal packing gives dense, low-porosity walls. | 110 | 250 | 16 | 65 HB | 26 % IACS |
What is CC750S-GM?
CC750S-GM is CC750S supplied in the GM condition — pick for higher-volume small parts needing better surface, tighter tolerance and ~20 % higher strength from the finer chill structure. CC750S-GM has a yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 97 GPa (14.1 Msi). CC750S-GM has a density of 8.5 g/cm³ (0.307 lb/in³), lighter than 65% of copper alloy grades. It melts at 900°C (1,652 °F). GS is the default condition FabDigit quotes; GM is available on request or by drawing note.
Advantages
- Easy to machine — 85/100, better than 93% of copper alloy grades
- Low embodied carbon — 3.2 kg CO₂/kg, better than 92% of copper alloy grades
Limitations
- Low stiffness — 97 GPa (14.1 Msi), worse than 88% of copper alloy grades
- Difficult to weld — 20/100, worse than 88% of copper alloy grades
- Low strength — 110 MPa (16 ksi), worse than 82% of copper alloy grades
CC750S-GM properties
Typical room-temperature values for CC750S-GM; 21 are specific to this condition. Other listed values are CC750S reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
CC750S-GM has a density of 8.5 g/cm³ (0.307 lb/in³), lighter than 65% of copper alloy grades. It melts at 900°C (1,652 °F).
Mechanical15
CC750S-GM has a yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 97 GPa (14.1 Msi).
Thermal6
CC750S-GM is rated for continuous service to 200°C (392 °F). It conducts heat at 115 W/m·K (66.4 BTU/hr·ft·°F), better than 61% of copper alloy grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
CC750S-GM conducts electricity at 26 % IACS, better than 63% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (53/100), worse than 92% of copper alloy grades.
Sustainability4
Producing a kilogram of CC750S-GM takes about 45 MJ of energy and emits 3.2 kg of CO₂ — less than 97% of copper alloy grades. Typical recycled content is 85%.
Manufacturability8
CC750S-GM's machinability is excellent (85/100, better than 93% of copper alloy grades); weldability poor (20/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CC750S-GM
Is CC750S easy to machine?
Free-cutting: high speeds with sharp zero/negative-rake carbide or HSS tools, light feeds, water-soluble coolant; chips break short thanks to the 2 % Pb, but extract lead-bearing dust.
Can CC750S be welded?
Not recommended for fusion welding — zinc fumes and lead-induced hot cracking; repair by brazing with low-temperature Ag or Cu-P filler, or mechanically join.
Can CC750S be formed, bent or molded?
Casting alloy with excellent fluidity and low shrinkage; use generous fillets, chill or feed heavy sections, degas the melt and cover with charcoal/flux to limit zinc loss; avoid cold forming of finished castings.
What surface finishes work on CC750S?
Buffs to bright brass, takes lacquer, chemical patina and Ni/Cr or brass electroplating; not anodisable, and porosity or lead smearing can pit a plated finish if not pre-cleaned.
CC750S 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 | 63 – 67 | 65 |
| Pbfree-machining constituent | 1 – 3 | 2 |
| Sn | ≤ 1 | 0.3 |
| Fe | ≤ 0.8 | 0.2 |
| Ni | ≤ 1 | 0.2 |
| Al | ≤ 0.5 | 0.05 |
| Mn | ≤ 0.5 | 0.05 |
| Sb | ≤ 0.1 | — |
| Si | ≤ 0.05 | — |
| others (total)sum of unlisted impurities | ≤ 1 | — |
| Znremainder, nominally 31–35 % | balance | — |
CC750S-GM — frequently asked
What is CC750S-GM used for?
CC750S-GM is typically used for hardware fittings, decorative castings and plumbing components. In short: baseline leaded casting brass; free-cutting and easy to plate; good castability, modest strength.
What is the yield strength of CC750S-GM?
CC750S-GM has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 82% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is CC750S-GM easy to machine?
Yes — machinability is rated excellent (85/100, better than 93% of copper alloy grades). Free-cutting: high speeds with sharp zero/negative-rake carbide or HSS tools, light feeds, water-soluble coolant; chips break short thanks to the 2 % Pb, but extract lead-bearing dust.
Can CC750S-GM be welded?
Not readily — weldability is rated poor (20/100). Not recommended for fusion welding — zinc fumes and lead-induced hot cracking; repair by brazing with low-temperature Ag or Cu-P filler, or mechanically join.
What surface finishes work on CC750S-GM?
Buffs to bright brass, takes lacquer, chemical patina and Ni/Cr or brass electroplating; not anodisable, and porosity or lead smearing can pit a plated finish if not pre-cleaned.
Can CC750S-GM be formed, bent or molded?
Casting alloy with excellent fluidity and low shrinkage; use generous fillets, chill or feed heavy sections, degas the melt and cover with charcoal/flux to limit zinc loss; avoid cold forming of finished castings.
What is the maximum service temperature of CC750S-GM?
CC750S-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 CC750S-GS and CC750S-GM?
GS is the default condition — default condition for general hardware, decorative and low-pressure fittings poured in sand or shell moulds. GM: pick for higher-volume small parts needing better surface, tighter tolerance and ~20 % higher strength from the finer chill structure. Yield strength is 90 MPa in GS versus 110 MPa in GM.
Sources
- EN 1982 — Copper and copper alloys: ingots and castings — CEN (2017)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- DKI Kupfer-Werkstoff-Datenblätter (Cu-Zn-Pb Gusslegierungen) — Deutsches Kupferinstitut (2020)
- Copper Alloy Datasheets / machinability ratings — Copper Development Association (copper.org) (2023)
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.