Copper Alloy CC764S-SR (Stress relieved)
Heat-treated state
EN CC764S
Order when residual stresses must be reduced before precision machining or to lower stress-corrosion risk in ammoniacal service.
Values for the SR condition
Other CC764S tempers and conditions
CC764S is listed in 5 conditions; see the grade overview at CC764S.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | Order when residual stresses must be reduced before precision machining or to lower stress-corrosion risk in ammoniacal service. | 370 | 660 | 20 | 165 HB | 8.5 % IACS |
GSDefault Sand cast | Default condition for large or one-off marine and machinery castings; lowest strength of the four routes but best for complex shapes. | 390 | 680 | 18 | 170 HB | — |
Permanent (metal) mould / chill cast | Pick for series parts where the finer chill-cast structure raises strength and hardness over sand casting. | 450 | 740 | 15 | 185 HB | 8 % IACS |
Continuously cast bar / tube | Stock form for machined bushings, nuts and wear plates cut from continuous-cast bar or hollow. | 460 | 750 | 13 | 185 HB | 8 % IACS |
Centrifugally cast | Best choice for bushings, sleeves and gear rims — dense, porosity-free rings with the highest strength. | 470 | 780 | 14 | 190 HB | 8 % IACS |
What is CC764S-SR?
CC764S-SR is CC764S heat treated to SR — order when residual stresses must be reduced before precision machining or to lower stress-corrosion risk in ammoniacal service. CC764S-SR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 100 GPa (14.5 Msi). CC764S-SR has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 90% of copper alloy grades. It melts at 875°C (1,607 °F). GS is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High strength — 370 MPa (53.7 ksi), better than 75% of copper alloy grades
Limitations
- Hard to polish — 60/100, worse than 92% of copper alloy grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades
- Low stiffness — 100 GPa (14.5 Msi), worse than 82% of copper alloy grades
- Low electrical conductivity — 8.5 % IACS, worse than 79% of copper alloy grades
- Limited formability — 18/100, worse than 75% of copper alloy grades
CC764S-SR properties
Typical room-temperature values for CC764S-SR; 21 are specific to this condition. Other listed values are CC764S reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
CC764S-SR has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 90% of copper alloy grades. It melts at 875°C (1,607 °F).
Mechanical14
CC764S-SR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
CC764S-SR is rated for continuous service to 200°C (392 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
CC764S-SR conducts electricity at 8.5 % IACS, worse than 79% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 68% of copper alloy grades.
Sustainability4
Producing a kilogram of CC764S-SR takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 50%.
Manufacturability7
CC764S-SR's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability poor (28/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CC764S-SR
Is CC764S easy to machine?
Machines like a tough alpha-beta brass — rigid setups, sharp carbide tooling, moderate speeds and generous coolant; chips are stringy, so it cuts far slower than free-cutting C36000.
Can CC764S be welded?
Fusion welding is generally avoided (Zn fume, hot cracking); minor defects are repaired by GTAW/GMAW with matching Al-brass or Ni-Al-bronze filler, preheating and post-weld stress relief.
Can CC764S be formed, bent or molded?
Casting alloy only — pour at about 1000–1050 °C with chills/risers on heavy sections to avoid shrinkage porosity; no cold forming.
What surface finishes work on CC764S?
Takes a bright mechanical polish and can be nickel- or chrome-plated after thorough Al-oxide removal; leave a machining allowance on cast surfaces and avoid strong ammonia-based cleaners.
CC764S 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 | 60 – 66 | 63 |
| Mn | 2 – 4 | 3 |
| Al | 1 – 2.5 | 2 |
| Fe | 0.5 – 1.5 | 1 |
| Niimpurity limit | ≤ 1 | — |
| Snimpurity limit | ≤ 0.4 | — |
| Pbimpurity limit | ≤ 0.5 | — |
| Siimpurity limit | ≤ 0.1 | — |
| Zn | balance | — |
CC764S-SR — frequently asked
What is CC764S-SR used for?
CC764S-SR is typically used for propeller hubs, structural marine parts and high-load bushings. In short: strongest cast manganese brass; high-load marine castings; low machinability rating.
What is the yield strength of CC764S-SR?
CC764S-SR has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 75% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is CC764S-SR easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Machines like a tough alpha-beta brass — rigid setups, sharp carbide tooling, moderate speeds and generous coolant; chips are stringy, so it cuts far slower than free-cutting C36000.
Can CC764S-SR be welded?
Not readily — weldability is rated poor (28/100). Fusion welding is generally avoided (Zn fume, hot cracking); minor defects are repaired by GTAW/GMAW with matching Al-brass or Ni-Al-bronze filler, preheating and post-weld stress relief.
What surface finishes work on CC764S-SR?
Takes a bright mechanical polish and can be nickel- or chrome-plated after thorough Al-oxide removal; leave a machining allowance on cast surfaces and avoid strong ammonia-based cleaners.
Can CC764S-SR be formed, bent or molded?
Casting alloy only — pour at about 1000–1050 °C with chills/risers on heavy sections to avoid shrinkage porosity; no cold forming.
What is the maximum service temperature of CC764S-SR?
CC764S-SR 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 CC764S-GS and CC764S-GZ?
GS is the default condition — default condition for large or one-off marine and machinery castings; lowest strength of the four routes but best for complex shapes. GZ: best choice for bushings, sleeves and gear rims — dense, porosity-free rings with the highest strength. Yield strength is 390 MPa in GS versus 470 MPa in GZ.
Sources
- EN 1982 — Copper and copper alloys: ingots and castings — CEN (2017)
- C86300 High-Strength Manganese Bronze alloy datasheet — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- ASTM B584 — Copper Alloy Sand Castings for General Applications — ASTM (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.