Copper Alloy C33000-O (Annealed)
Temper · default condition
UNS C33000 · ASTM B135
Softest condition — pick for tight-radius bending, expanding, flaring and forming of tube.
Values for the O condition
Other C33000 tempers and conditions
C33000 is listed in 7 conditions; see the grade overview at C33000.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Light annealed | Light anneal for a balance of formability and handling stiffness in coiled or straight tube. | 105 | 320 | 58 | 50 HB | 26 % IACS |
ODefaultThis page Annealed | Softest condition — pick for tight-radius bending, expanding, flaring and forming of tube. | 110 | 340 | 55 | 55 HB | 26 % IACS |
Light drawn | Lightly drawn tube — better straightness and strength than annealed while still bendable. | 200 | 360 | 40 | 85 HB | 26 % IACS |
Drawn, general purpose | Most common as-drawn tube temper for general plumbing/heat-exchanger and machined-fitting stock. | 250 | 390 | 30 | 100 HB | 26 % IACS |
Half hard | Half-hard drawn tube/rod — good compromise of strength, screw-machine performance and moderate forming. | 275 | 420 | 25 | 110 HB | — |
Full hard | Full-hard drawn condition for maximum strength, straightness and best turning finish; little cold forming left. | 390 | 500 | 8 | 145 HB | — |
Hard drawn | Heavily drawn tube for maximum burst/pressure rating and rigid straight lengths. | 415 | 520 | 6 | 155 HB | 26 % IACS |
What is C33000-O?
C33000-O is C33000 in the O temper — softest condition — pick for tight-radius bending, expanding, flaring and forming of tube. C33000-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 55% and the elastic modulus is 103 GPa (14.9 Msi). C33000-O has a density of 8.47 g/cm³ (0.306 lb/in³), lighter than 68% of copper alloy grades. It melts at 899°C (1,650 °F).
Advantages
- Ductile — tolerates forming and impact — 55%, better than 98% of copper alloy grades
- Forms and bends easily — 85/100, better than 85% of copper alloy grades
- Easy to machine — 70/100, better than 78% of copper alloy grades
Limitations
- Low strength — 110 MPa (16 ksi), worse than 82% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C33000-O properties
Typical room-temperature values for C33000-O; 19 are specific to this condition. Other listed values are C33000 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C33000-O has a density of 8.47 g/cm³ (0.306 lb/in³), lighter than 68% of copper alloy grades. It melts at 899°C (1,650 °F).
Mechanical13
C33000-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 55% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C33000-O is rated for continuous service to 200°C (392 °F). It conducts heat at 121 W/m·K (69.9 BTU/hr·ft·°F), better than 68% of copper alloy grades. Thermal expansion is 20.2 µm/m·K (11.2 µin/in·°F).
Electrical3
C33000-O conducts electricity at 26 % IACS, better than 63% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of C33000-O 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
C33000-O's machinability is very good (70/100, better than 78% of copper alloy grades); weldability poor (25/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C33000-O
Is C33000 easy to machine?
Free-cutting-like behaviour at ~80–90% of C36000: use positive-rake carbide or HSS, high speed, light feeds, water-soluble coolant; chips break well thanks to the 0.5% Pb.
Can C33000 be welded?
Not suited to fusion welding (lead cracking and Zn fume); join by soft soldering or silver brazing with flux and controlled heat.
Can C33000 be formed, bent or molded?
Annealed/O50 tube bends, expands, flares and knurls readily; interanneal ~425–600 °C between heavy draws and stress-relieve cold-worked parts (~250–300 °C) to avoid ammonia-induced SCC.
What surface finishes work on C33000?
Polishes to a bright yellow finish; accepts nickel/chrome plating, chemical blackening/antiquing and clear lacquer — no anodizing.
C33000 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 | 65 – 68 | 66 |
| Pbfree-machining addition | 0.25 – 0.7 | 0.5 |
| Fe | ≤ 0.07 | |
| Znremainder, nominally ~33.5% | balance |
C33000-O — frequently asked
What is C33000-O used for?
C33000-O is typically used for heat exchanger and condenser tubes, gas and liquid transfer tubing, machined tube fittings, lighting fixture tubing, hardware and decorative tube and instrument and gauge lines. In short: ductile heat-exchanger brass.
What is the yield strength of C33000-O?
C33000-O has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C33000-O easy to machine?
Yes — machinability is rated very good (70/100, better than 78% of copper alloy grades). Free-cutting-like behaviour at ~80–90% of C36000: use positive-rake carbide or HSS, high speed, light feeds, water-soluble coolant; chips break well thanks to the 0.5% Pb.
Can C33000-O be welded?
Not readily — weldability is rated poor (25/100). Not suited to fusion welding (lead cracking and Zn fume); join by soft soldering or silver brazing with flux and controlled heat.
What surface finishes work on C33000-O?
Polishes to a bright yellow finish; accepts nickel/chrome plating, chemical blackening/antiquing and clear lacquer — no anodizing.
Can C33000-O be formed, bent or molded?
Annealed/O50 tube bends, expands, flares and knurls readily; interanneal ~425–600 °C between heavy draws and stress-relieve cold-worked parts (~250–300 °C) to avoid ammonia-induced SCC.
What is the maximum service temperature of C33000-O?
C33000-O 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 C33000-O and C33000-H80?
O is the default condition — softest condition — pick for tight-radius bending, expanding, flaring and forming of tube. H80: heavily drawn tube for maximum burst/pressure rating and rigid straight lengths. Yield strength is 110 MPa in O versus 415 MPa in H80.
Can FabDigit make parts in C33000-O?
Yes — C33000-O is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B135 — Seamless Brass Tube — ASTM International (2017)
- CDA Alloy Datasheet C33000 (Low-Leaded Brass Tube) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion of Copper and 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.