Copper Alloy PBC2-CF (Centrifugally cast)
Reinforced grade
Best for large worm-gear rims and bushing sleeves: dense, porosity-free wall with the highest strength/hardness of the cast forms.
Values for the CF condition
Other PBC2 tempers and conditions
PBC2 is listed in 5 conditions; see the grade overview at PBC2.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Use for precision gears/bushings where casting residual stress would cause distortion during finish machining. | 150 | 295 | 16 | 78 HB | 11 % IACS |
SCDefault Sand cast | General-purpose condition for one-off and low-volume worm wheels, gear rims and bearing blanks. | 152 | 300 | 15 | 80 HB | 11 % IACS |
PBC2B, higher-phosphorus variant | Pick when maximum hardness and anti-galling performance are required for heavily loaded worm wheels; slightly less ductile. | 165 | 295 | 8 | 90 HB | 10 % IACS |
Permanent mold / chill cast | Choose for repeat production of small gears/bushings needing finer structure and higher hardness than sand cast. | 185 | 330 | 12 | 95 HB | 11 % IACS |
CFThis page Centrifugally cast | Best for large worm-gear rims and bushing sleeves: dense, porosity-free wall with the highest strength/hardness of the cast forms. | 207 | 345 | 14 | 102 HB | 11 % IACS |
What is PBC2-CF?
PBC2-CF is PBC2 in the CF grade — best for large worm-gear rims and bushing sleeves: dense, porosity-free wall with the highest strength/hardness of the cast forms. PBC2-CF has a yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Elongation at break is 14% and the elastic modulus is 105 GPa (15.2 Msi). PBC2-CF has a density of 8.77 g/cm³ (0.317 lb/in³), heavier than 52% of copper alloy grades. It melts at 831°C (1,528 °F). SC is the default condition FabDigit quotes; CF is available on request or by drawing note.
Limitations
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
- Limited formability — 10/100, worse than 89% of copper alloy grades
- Hard to polish — 65/100, worse than 87% of copper alloy grades
- High embodied carbon — 5 kg CO₂/kg, worse than 86% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
PBC2-CF properties
Typical room-temperature values for PBC2-CF; 21 are specific to this condition. Other listed values are PBC2 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
PBC2-CF has a density of 8.77 g/cm³ (0.317 lb/in³), heavier than 52% of copper alloy grades. It melts at 831°C (1,528 °F).
Mechanical15
PBC2-CF has a yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Elongation at break is 14% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
PBC2-CF is rated for continuous service to 250°C (482 °F). It conducts heat at 71 W/m·K (41 BTU/hr·ft·°F), worse than 54% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
PBC2-CF conducts electricity at 11 % IACS, worse than 68% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 52% of copper alloy grades.
Sustainability4
Producing a kilogram of PBC2-CF takes about 70 MJ of energy and emits 5 kg of CO₂ — more than 84% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
PBC2-CF's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability poor (25/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PBC2-CF
Is PBC2 easy to machine?
Machinability ~20 % of free-cutting brass; the hard δ phase makes chips short but abrasive — use sharp carbide, positive rake, moderate speed with flood coolant, and expect good surface finish for bearing bores.
Can PBC2 be welded?
Poor fusion weldability (hot-short, tin oxide/porosity); repair by braze welding with phosphor-bronze rod and preheat 150–200 °C, or use silver brazing/soldering instead.
Can PBC2 be formed, bent or molded?
Not cold formable — supply as sand, permanent-mold, centrifugal or continuous castings; wide freezing range demands chills, generous risers and directional solidification to avoid tin sweat and microporosity.
What surface finishes work on PBC2?
No anodizing; finish by machining/burnishing, chemical patina or lacquer, and tin or nickel plate where contact corrosion with steel is a concern.
PBC2 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 |
|---|---|---|
| SnJIS CAC502A / ASTM C90700 10–12 % | 9 – 12 | 11 |
| PCAC502B (PBC2B): 0.15–0.50 % | 0.05 – 0.35 | 0.2 |
| Znimpurity limit | ≤ 0.5 | — |
| Pb0.20 max in JIS CAC502A | ≤ 0.5 | — |
| Fe | ≤ 0.15 | — |
| Ni | ≤ 1 | — |
| Sb | ≤ 0.2 | — |
| Al | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| S | ≤ 0.05 | — |
| Cu | ≥ 87 (balance) | — |
PBC2-CF — frequently asked
What is PBC2-CF used for?
PBC2-CF is typically used for worm gears, wear plates and high-load bushings. In short: high-wear gear bronze; highest-tin bearing bronze; hardest of the tin bronzes.
What is the yield strength of PBC2-CF?
PBC2-CF has a typical yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is PBC2-CF easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Machinability ~20 % of free-cutting brass; the hard δ phase makes chips short but abrasive — use sharp carbide, positive rake, moderate speed with flood coolant, and expect good surface finish for bearing bores.
Can PBC2-CF be welded?
Not readily — weldability is rated poor (25/100). Poor fusion weldability (hot-short, tin oxide/porosity); repair by braze welding with phosphor-bronze rod and preheat 150–200 °C, or use silver brazing/soldering instead.
What surface finishes work on PBC2-CF?
No anodizing; finish by machining/burnishing, chemical patina or lacquer, and tin or nickel plate where contact corrosion with steel is a concern.
Can PBC2-CF be formed, bent or molded?
Not cold formable — supply as sand, permanent-mold, centrifugal or continuous castings; wide freezing range demands chills, generous risers and directional solidification to avoid tin sweat and microporosity.
What is the maximum service temperature of PBC2-CF?
PBC2-CF is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between PBC2-SC and PBC2-CF?
SC is the default condition — general-purpose condition for one-off and low-volume worm wheels, gear rims and bearing blanks. CF: best for large worm-gear rims and bushing sleeves: dense, porosity-free wall with the highest strength/hardness of the cast forms. Yield strength is 152 MPa in SC versus 207 MPa in CF.
Sources
- JIS H 5120 — Copper alloy castings (CAC502A/B, formerly PBC2/PBC2B) — JISC (2016)
- ASTM B505/B505M — Continuous cast copper alloys (C90700) — ASTM (2018)
- ASTM B427 — Gear bronze alloy castings — ASTM (2019)
- CDA alloy datasheet C90700 — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — 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.