Copper Alloy BC6-PM (Permanent mould / chill cast)
Finish state
GB BC6
Pick for medium-volume small fittings needing tighter dimensions and a finer, slightly stronger chill-cast structure.
Values for the PM condition
Other BC6 tempers and conditions
BC6 is listed in 2 conditions; see the grade overview at BC6.
- F-SAND
- PM
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
F-SANDDefault F | Standard sand-cast condition for valve bodies, pump housings and marine fittings; most widely stocked and quoted. | 110 | 250 | 25 | 60 HB | 15 % IACS |
PMThis page Permanent mould / chill cast | Pick for medium-volume small fittings needing tighter dimensions and a finer, slightly stronger chill-cast structure. | 120 | 260 | 20 | 65 HB | 15 % IACS |
What is BC6-PM?
BC6-PM is BC6 supplied in the PM condition — pick for medium-volume small fittings needing tighter dimensions and a finer, slightly stronger chill-cast structure. BC6-PM has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 79% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 96 GPa (13.9 Msi). BC6-PM has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 854°C (1,569 °F). F-SAND is the default condition FabDigit quotes; PM is available on request or by drawing note.
Advantages
- Easy to machine — 85/100, better than 93% of copper alloy grades
Limitations
- Hard to polish — 60/100, worse than 92% of copper alloy grades
- Low stiffness — 96 GPa (13.9 Msi), worse than 91% of copper alloy grades
- Difficult to weld — 20/100, worse than 88% of copper alloy grades
- High embodied carbon — 4.6 kg CO₂/kg, worse than 82% of copper alloy grades
- Low strength — 120 MPa (17.4 ksi), worse than 79% of copper alloy grades
BC6-PM properties
Typical room-temperature values for BC6-PM; 20 are specific to this condition. Other listed values are BC6 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
BC6-PM has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 854°C (1,569 °F).
Mechanical15
BC6-PM has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 79% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 96 GPa (13.9 Msi).
Thermal6
BC6-PM is rated for continuous service to 230°C (446 °F). It conducts heat at 72 W/m·K (41.6 BTU/hr·ft·°F), worse than 52% of copper alloy grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
BC6-PM conducts electricity at 15 % IACS, worse than 54% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of BC6-PM takes about 62 MJ of energy and emits 4.6 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 75%.
Manufacturability7
BC6-PM's machinability is excellent (85/100, better than 93% of copper alloy grades); weldability poor (20/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BC6-PM
Is BC6 easy to machine?
Excellent free-cutting behaviour (~84 % of C36000); use sharp positive-rake tools, high speed, light feed, and soluble-oil or dry cutting — lead gives short chips and fine bore finishes.
Can BC6 be welded?
Fusion welding is poor because of the 5 % lead (hot cracking, porosity); repair by brazing or low-fume TIG with matched filler only on non-critical, non-pressure areas.
Can BC6 be formed, bent or molded?
Cast-only alloy with wide freezing range — excellent fluidity and pressure tightness in sand, chill, centrifugal and continuous casting; not cold formable.
What surface finishes work on BC6?
Machines to a good matte finish; readily soldered, tin- or nickel-plated and chemically patinated/lacquered; polishing is limited by lead smear and micro-porosity.
BC6 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 |
|---|---|---|
| CuJIS H5120 CAC406 | 83 – 87 | 85 |
| Sn | 4 – 6 | 5 |
| Pbfree-machining / pressure-tightness aid; restricted by lead-free potable-water rules | 4 – 6 | 5 |
| Fe | ≤ 0.3 | — |
| Nicounted with Cu in some editions | ≤ 1 | — |
| Sb | ≤ 0.2 | — |
| P | ≤ 0.05 | — |
| Al | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| S | ≤ 0.05 | — |
| Zn | ≥ 4 (balance) | — |
BC6-PM — frequently asked
What is BC6-PM used for?
BC6-PM is typically used for pump bodies, valve fittings and marine components. In short: best-machining cast bronze; pressure-tight pump bronze; not fusion weldable.
What is the yield strength of BC6-PM?
BC6-PM has a typical yield strength of 120 MPa (17.4 ksi) and a tensile strength of 260 MPa (37.7 ksi) — weaker than 79% of copper alloy grades. Strength varies by condition: see the 2 listed tempers.
Is BC6-PM easy to machine?
Yes — machinability is rated excellent (85/100, better than 93% of copper alloy grades). Excellent free-cutting behaviour (~84 % of C36000); use sharp positive-rake tools, high speed, light feed, and soluble-oil or dry cutting — lead gives short chips and fine bore finishes.
Can BC6-PM be welded?
Not readily — weldability is rated poor (20/100). Fusion welding is poor because of the 5 % lead (hot cracking, porosity); repair by brazing or low-fume TIG with matched filler only on non-critical, non-pressure areas.
What surface finishes work on BC6-PM?
Machines to a good matte finish; readily soldered, tin- or nickel-plated and chemically patinated/lacquered; polishing is limited by lead smear and micro-porosity.
Can BC6-PM be formed, bent or molded?
Cast-only alloy with wide freezing range — excellent fluidity and pressure tightness in sand, chill, centrifugal and continuous casting; not cold formable.
What is the maximum service temperature of BC6-PM?
BC6-PM is rated for continuous use to about 230°C (446 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BC6 F-SAND and BC6-PM?
F-SAND is the default condition — standard sand-cast condition for valve bodies, pump housings and marine fittings; most widely stocked and quoted. PM: pick for medium-volume small fittings needing tighter dimensions and a finer, slightly stronger chill-cast structure. Yield strength is 110 MPa in F-SAND versus 120 MPa in PM.
Sources
- JIS H5120 Copper alloy castings (CAC406 / former BC6) — JSA (2016)
- ASTM B584 Standard Specification for Copper Alloy Sand Castings (C83600) — ASTM (2021)
- CDA Alloy Datasheet C83600 (85-5-5-5 leaded red brass) — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (Copper alloys in seawater) — ASM International (2005)
- GB/T 1176 (ZCuSn5Pb5Zn5) — SAC (2013)
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.