Copper Alloy C33000-O50
Temper
UNS C33000 · ASTM B135
O50 = light annealed
Light anneal for a balance of formability and handling stiffness in coiled or straight tube.
Values for the O50 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 |
|---|---|---|---|---|---|---|
O50This page Light annealed | Light anneal for a balance of formability and handling stiffness in coiled or straight tube. | 105 | 320 | 58 | 50 HB | 26 % IACS |
ODefault 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-O50?
C33000-O50 is C33000 in the O50 temper — light anneal for a balance of formability and handling stiffness in coiled or straight tube. C33000-O50 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 58% and the elastic modulus is 103 GPa (14.9 Msi). C33000-O50 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). O is the default condition FabDigit quotes; O50 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 58%, better than 99% of copper alloy grades
- Forms and bends easily — 88/100, better than 87% of copper alloy grades
- Easy to machine — 80/100, better than 86% of copper alloy grades
Limitations
- Low strength — 105 MPa (15.2 ksi), worse than 85% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C33000-O50 properties
Typical room-temperature values for C33000-O50; 18 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-O50 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-O50 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 58% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C33000-O50 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-O50 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-O50 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-O50's machinability is very good (80/100, better than 86% of copper alloy grades); weldability poor (25/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C33000-O50
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-O50 — frequently asked
What is C33000-O50 used for?
C33000-O50 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-O50?
C33000-O50 has a typical yield strength of 105 MPa (15.2 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 85% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C33000-O50 easy to machine?
Yes — machinability is rated very good (80/100, better than 86% 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-O50 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-O50?
Polishes to a bright yellow finish; accepts nickel/chrome plating, chemical blackening/antiquing and clear lacquer — no anodizing.
Can C33000-O50 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-O50?
C33000-O50 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-O50?
Yes — C33000-O50 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.