Copper Alloy C66300-O60
Temper
UNS C66300 · ASTM B592
O60 = soft annealed
Pick for deep drawing, severe forming or re-rolling before final temper rolling.
Values for the O60 condition
Other C66300 tempers and conditions
C66300 is listed in 11 conditions; see the grade overview at C66300.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O60This page Soft annealed | Pick for deep drawing, severe forming or re-rolling before final temper rolling. | 145 | 375 | 45 | 85 HB | 27 % IACS |
Annealed to temper, half-hard level | Use where half-hard strength is needed together with a fully recrystallised, forming-friendly structure and low residual stress. | 275 | 450 | 25 | 60 HRB | — |
Half hard | General-purpose stamping temper when moderate strength plus some bend ductility is required. | 400 | 500 | 15 | 68 HRB | — |
Full hard | Standard stocked hard strip for fasteners, clips and lightly loaded flat springs. | 490 | 570 | 8 | 78 HRB | — |
Full hard and stress relieved | Choose when full-hard strength must be combined with low residual stress (flatness, reduced SCC risk in ammonia-bearing service). | 540 | 585 | 8 | 79 HRB | — |
Extra hard | Step up from full hard for higher elastic limit where only gentle forming (bends along grain) is needed. | 550 | 620 | 5 | 82 HRB | — |
H08Default Spring hard | Default stocked spring-strip temper: best balance of elastic limit and formability for stamped springs and contacts. | 600 | 660 | 3.5 | 85 HRB | — |
Spring temper and stress relieved | Spring temper with a low-temperature stress relief for higher elastic limit, better flatness and less relaxation in service. | 630 | 670 | 3.5 | 86 HRB | — |
Extra spring hard | For higher spring rate and load capacity in flat springs where bend radii can be kept large. | 640 | 700 | 3 | 88 HRB | — |
Extra spring temper and stress relieved | Extra-spring strip stabilised by stress relief for maximum elastic limit with controlled flatness and reduced SCC sensitivity. | 670 | 710 | 3 | 89 HRB | — |
Strain hardened, half hard | Maximum cold-rolled strength for very high spring loads in flat parts with minimal forming. | 690 | 740 | 2 | 90 HRB | — |
What is C66300-O60?
C66300-O60 is C66300 in the O60 temper — pick for deep drawing, severe forming or re-rolling before final temper rolling. C66300-O60 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 375 MPa (54.4 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 110 GPa (16 Msi). C66300-O60 has a density of 8.55 g/cm³ (0.309 lb/in³), lighter than 60% of copper alloy grades. It melts at 900°C (1,652 °F). H08 is the default condition FabDigit quotes; O60 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 45%, better than 91% of copper alloy grades
- Forms and bends easily — 90/100, better than 89% of copper alloy grades
Limitations
- Difficult to machine — 25/100, worse than 86% of copper alloy grades
C66300-O60 properties
Typical room-temperature values for C66300-O60; 20 are specific to this condition. Other listed values are C66300 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C66300-O60 has a density of 8.55 g/cm³ (0.309 lb/in³), lighter than 60% of copper alloy grades. It melts at 900°C (1,652 °F).
Mechanical11
C66300-O60 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 375 MPa (54.4 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C66300-O60 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 19.9 µm/m·K (11.1 µin/in·°F).
Electrical3
C66300-O60 conducts electricity at 27 % IACS, better than 67% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C66300-O60 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%.
Manufacturability7
C66300-O60's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability poor (32/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C66300-O60
Is C66300 easy to machine?
Unleaded tin brass machines to roughly 30 % of free-cutting brass — use sharp positive-rake tools, high speed, light feed and emulsion coolant to avoid gummy chips.
Can C66300 be welded?
Not suited to fusion arc welding (zinc fume/porosity); join by resistance spot/seam welding, soft soldering or silver brazing with ventilation.
Can C66300 be formed, bent or molded?
Blank and form from O82/H02 for deep shapes; in spring tempers bend with the bend axis across the rolling direction and generous radii, then stress-relieve stamped springs at ~200–250 °C to set shape and cut relaxation.
What surface finishes work on C66300?
Takes bright mechanical polishing; commonly tin-, nickel-, silver- or gold-plated for contacts, or lacquered/passivated to prevent tarnish. No anodising.
C66300 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 |
|---|---|---|
| Curegistered range per CDA/ASTM listing for this Cu-Zn-Sn alloy — verify against the current standard before ordering | 68.5 – 71.5 | 70 |
| Sntin addition for strength and dezincification resistance | 2 – 3 | 2.5 |
| Feimpurity limit | ≤ 0.05 | — |
| Pbimpurity limit | ≤ 0.05 | — |
| Znremainder, nominally ~27 % | balance | — |
C66300-O60 — frequently asked
What is C66300-O60 used for?
C66300-O60 is typically used for springs, fasteners, electrical contacts and precision stampings. In short: spring-temper tin brass; 600 MPa yield strip; low formability, high strength.
What is the yield strength of C66300-O60?
C66300-O60 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 375 MPa (54.4 ksi) — weaker than 72% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C66300-O60 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Unleaded tin brass machines to roughly 30 % of free-cutting brass — use sharp positive-rake tools, high speed, light feed and emulsion coolant to avoid gummy chips.
Can C66300-O60 be welded?
Not readily — weldability is rated poor (32/100). Not suited to fusion arc welding (zinc fume/porosity); join by resistance spot/seam welding, soft soldering or silver brazing with ventilation.
What surface finishes work on C66300-O60?
Takes bright mechanical polishing; commonly tin-, nickel-, silver- or gold-plated for contacts, or lacquered/passivated to prevent tarnish. No anodising.
Can C66300-O60 be formed, bent or molded?
Blank and form from O82/H02 for deep shapes; in spring tempers bend with the bend axis across the rolling direction and generous radii, then stress-relieve stamped springs at ~200–250 °C to set shape and cut relaxation.
What is the maximum service temperature of C66300-O60?
C66300-O60 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 C66300-H08 and C66300-O60?
H08 is the default condition — default stocked spring-strip temper: best balance of elastic limit and formability for stamped springs and contacts. O60: pick for deep drawing, severe forming or re-rolling before final temper rolling. Yield strength is 600 MPa in H08 versus 145 MPa in O60.
Sources
- ASTM B592 — Copper-alloy plate, sheet, strip and rolled bar (Cu-Zn based high-strength alloys) — ASTM International (2021)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
- CDA/copper.org Standard Designations & Alloy Property Database — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous 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.