Copper Alloy C66700-OS050
Temper
UNS C66700
OS050 = annealed to 0.050 mm grain size
Softest commercial temper for deep drawing and severe bending of strip.
Values for the OS050 condition
Other C66700 tempers and conditions
C66700 is listed in 9 conditions; see the grade overview at C66700.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OS050This page Annealed to 0.050 mm grain size | Softest commercial temper for deep drawing and severe bending of strip. | 110 | 350 | 60 | 65 HB | — |
Annealed to 0.025 mm grain size | Fine-grain annealed strip: smoother formed surfaces and slightly higher strength than OS050. | 140 | 375 | 52 | 80 HB | — |
Quarter hard | Light cold work for parts needing moderate stiffness with generous bending. | 275 | 420 | 40 | 105 HB | — |
H02Default Half hard | Most-stocked balance of strength and formability for stamped hardware and fasteners. | 380 | 470 | 25 | 120 HB | — |
Three-quarter hard | Higher strength with limited bend capability, for load-carrying stampings. | 430 | 515 | 16 | 140 HB | — |
Full hard | Standard hard temper for flat springs, clips and wear-resistant stampings with only gentle forming. | 470 | 550 | 10 | 155 HB | — |
Extra hard | For high-stiffness contacts and wear parts where forming is limited to flat blanking. | 540 | 620 | 6 | 175 HB | — |
Spring hard | Spring temper strip/wire for high elastic-limit contacts and washers. | 580 | 660 | 4 | 190 HB | — |
Extra spring hard | Maximum cold-worked strength; brittle to bending, used for flat springs and thin high-load contacts. | 615 | 690 | 3 | 200 HB | — |
What is C66700-OS050?
C66700-OS050 is C66700 in the OS050 temper — softest commercial temper for deep drawing and severe bending of strip. C66700-OS050 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 60% and the elastic modulus is 110 GPa (16 Msi). C66700-OS050 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 915°C (1,679 °F). H02 is the default condition FabDigit quotes; OS050 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 60%, better than 99% of copper alloy grades
- Forms and bends easily — 88/100, better than 87% of copper alloy grades
Limitations
- Low strength — 110 MPa (16 ksi), worse than 82% of copper alloy grades
C66700-OS050 properties
Typical room-temperature values for C66700-OS050; 11 are specific to this condition. Other listed values are C66700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C66700-OS050 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 915°C (1,679 °F).
Mechanical12
C66700-OS050 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 60% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C66700-OS050 is rated for continuous service to 200°C (392 °F). It conducts heat at 84 W/m·K (48.5 BTU/hr·ft·°F), better than 51% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
C66700-OS050 conducts electricity at 17 % IACS, better than 50% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C66700-OS050 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
C66700-OS050's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability fair (45/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C66700-OS050
Is C66700 easy to machine?
Machinability roughly 30 % of free-cutting brass — gummy chips; use sharp positive-rake carbide, high speed, light feeds and good lubrication.
Can C66700 be welded?
Resistance and GTAW welding are fair; zinc volatilises so use ventilation and low heat input, and prefer brazing or soldering for joints.
Can C66700 be formed, bent or molded?
Excellent deep-draw and bend behaviour in OS tempers; interstage anneal at 425–600 °C, and stress-relieve cold-worked parts near 260 °C to avoid season cracking.
What surface finishes work on C66700?
Not anodisable; bright-dip, mechanically polish, or apply Ni/Cr, tin or clear lacquer — keep away from ammonia-based cleaners.
C66700 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 | 68.5 – 71.5 | 70 |
| Mnsolid-solution strengthener | 0.8 – 1.5 | 1.1 |
| Fe | ≤ 0.1 | — |
| Pb | ≤ 0.07 | — |
| Zn | balance | — |
C66700-OS050 — frequently asked
What is C66700-OS050 used for?
C66700-OS050 is typically used for fasteners, wear-resistant components and structural hardware. In short: manganese-strengthened drawing brass; 25 % elongation strip; stronger than cartridge brass.
What is the yield strength of C66700-OS050?
C66700-OS050 has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 82% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C66700-OS050 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Machinability roughly 30 % of free-cutting brass — gummy chips; use sharp positive-rake carbide, high speed, light feeds and good lubrication.
Can C66700-OS050 be welded?
With care — weldability is rated fair (45/100). Resistance and GTAW welding are fair; zinc volatilises so use ventilation and low heat input, and prefer brazing or soldering for joints.
What surface finishes work on C66700-OS050?
Not anodisable; bright-dip, mechanically polish, or apply Ni/Cr, tin or clear lacquer — keep away from ammonia-based cleaners.
Can C66700-OS050 be formed, bent or molded?
Excellent deep-draw and bend behaviour in OS tempers; interstage anneal at 425–600 °C, and stress-relieve cold-worked parts near 260 °C to avoid season cracking.
What is the maximum service temperature of C66700-OS050?
C66700-OS050 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 C66700-H02 and C66700-OS050?
H02 is the default condition — most-stocked balance of strength and formability for stamped hardware and fasteners. OS050: softest commercial temper for deep drawing and severe bending of strip. Yield strength is 380 MPa in H02 versus 110 MPa in OS050.
Sources
- CDA Alloy Data: C66700 Manganese Brass — Copper Development Association (copper.org) (2024)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASTM B36/B36M — Brass Plate, Sheet, Strip and Rolled Bar — ASTM (2018)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM (2019)
- ASM Handbook Vol.13B — Corrosion: Materials (copper alloys) — ASM International (2005)
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.