Copper Alloy C90700 BJ-S
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UNS C90700 · AISI/SAE 65 · EN CuSn10
BJ-S = binder jetted and sintered
Cost-effective route for complex small bearing/decorative parts; residual sintering porosity (3–8 %) lowers strength and conductivity.
Values for the BJ-S condition
Other C90700 tempers and conditions
C90700 is listed in 7 conditions; see the grade overview at C90700.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
BJ-SThis page Binder jetted and sintered | Cost-effective route for complex small bearing/decorative parts; residual sintering porosity (3–8 %) lowers strength and conductivity. | 140 | 270 | 8 | 70 HB | 8.5 % IACS |
M01Default As sand cast | Use the standard sand cast gear-bronze condition for worm wheels, bushings and one-off castings to ASTM B427, giving 305 MPa tensile, 80 HB and 12 % elongation without further treatment. | 152 | 305 | 12 | 80 HB | 10.9 % IACS |
Binder jetted, sintered and hot isostatically pressed | HIP closes residual pores for near-full density when pressure tightness or fatigue life is required. | 160 | 330 | 18 | 80 HB | 10.5 % IACS |
As centrifugally cast | Pick for bushings, sleeves and large-bore bearing blanks where a dense, directionally solidified wall is needed. | 175 | 330 | 11 | 90 HB | 10.9 % IACS |
As plaster cast | Chill casting refines the δ-network for higher strength and hardness in series-produced small gears and bushings. | 190 | 340 | 8 | 95 HB | 11 % IACS |
As continuous cast | Most-stocked bar and tube form: dense, low-porosity stock for machined bearings, wear plates and nuts. | 205 | 345 | 9 | 100 HB | 11 % IACS |
Cast and heat treated | Use when maximum gear-tooth hardness and load capacity are required from a C90700 casting; ductility drops sharply. | 250 | 380 | 5 | 120 HB | 11.5 % IACS |
What is C90700 BJ-S?
C90700 BJ-S is C90700 in the BJ-S condition — cost-effective route for complex small bearing/decorative parts; residual sintering porosity (3–8 %) lowers strength and conductivity. C90700 BJ-S has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 270 MPa (39.2 ksi) — weaker than 74% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 90 GPa (13.1 Msi). C90700 BJ-S has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 830°C (1,526 °F). M01 is the default condition FabDigit quotes; BJ-S is available on request or by drawing note.
Limitations
- Low stiffness — 90 GPa (13.1 Msi), worse than 95% of copper alloy grades
- Difficult to weld — 18/100, worse than 92% of copper alloy grades
- Limited formability — 10/100, worse than 89% of copper alloy grades
- Limited ductility — 8%, worse than 83% of copper alloy grades
- Poor heat conductor — 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 82% of copper alloy grades
C90700 BJ-S properties
Typical room-temperature values for C90700 BJ-S; 23 are specific to this condition. Other listed values are C90700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C90700 BJ-S has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 830°C (1,526 °F).
Mechanical15
C90700 BJ-S has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 270 MPa (39.2 ksi) — weaker than 74% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 90 GPa (13.1 Msi).
Thermal6
C90700 BJ-S is rated for continuous service to 250°C (482 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 82% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C90700 BJ-S conducts electricity at 8.5 % IACS, worse than 79% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C90700 BJ-S takes about 62 MJ of energy and emits 4.5 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
C90700 BJ-S's machinability is fair (45/100, better than 64% of copper alloy grades); weldability poor (18/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C90700 BJ-S
Is C90700 easy to machine?
Machines to fine chips with sharp positive-rake carbide or HSS tooling at 20–25 % of free-cutting brass rates; the hard δ-phase is abrasive, so use rigid setups, generous coolant and avoid rubbing to prevent smearing.
Can C90700 be welded?
Fusion welding is not recommended (hot-short, tin oxide inclusions); repair by GTAW with matching phosphor-bronze filler and preheat only when unavoidable — soldering and silver brazing are the preferred joining routes.
Can C90700 be formed, bent or molded?
Not cold formable — supplied as sand, chill, centrifugal or continuous castings, or gas-atomised powder for LPBF/binder jetting; pour 1150–1250 °C with good feeding to avoid inter-dendritic shrinkage porosity.
What surface finishes work on C90700?
Takes a bright turned or burnished surface, accepts tin, nickel and chrome plating and chemical patination (liver-of-sulphur/brown); no anodising — protect decorative parts with lacquer.
C90700 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 |
|---|---|---|
| SnZCuSn10P1 nominal 9.0–11.5 | 10 – 12 | 11 |
| Pdeoxidiser; GB ZCuSn10P1 allows 0.5–1.0 P | 0.05 – 0.3 | 0.2 |
| Pb | ≤ 0.5 | — |
| Zn | ≤ 0.5 | — |
| Niincl. Co | ≤ 0.5 | — |
| Fe | ≤ 0.15 | — |
| Sb | ≤ 0.2 | — |
| S | ≤ 0.05 | — |
| Al | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| Cu | ≥ 88 (balance) | — |
C90700 BJ-S — frequently asked
What is C90700 BJ-S used for?
C90700 BJ-S is typically used for bushings, bearings, decorative/art castings via AM and wear plates. In short: classic bearing bronze; binder-jet and LPBF friendly; good wear and machinability.
What is the yield strength of C90700 BJ-S?
C90700 BJ-S has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 270 MPa (39.2 ksi) — weaker than 74% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C90700 BJ-S easy to machine?
Reasonably — machinability is rated fair (45/100, better than 64% of copper alloy grades). Machines to fine chips with sharp positive-rake carbide or HSS tooling at 20–25 % of free-cutting brass rates; the hard δ-phase is abrasive, so use rigid setups, generous coolant and avoid rubbing to prevent smearing.
Can C90700 BJ-S be welded?
Not readily — weldability is rated poor (18/100). Fusion welding is not recommended (hot-short, tin oxide inclusions); repair by GTAW with matching phosphor-bronze filler and preheat only when unavoidable — soldering and silver brazing are the preferred joining routes.
What surface finishes work on C90700 BJ-S?
Takes a bright turned or burnished surface, accepts tin, nickel and chrome plating and chemical patination (liver-of-sulphur/brown); no anodising — protect decorative parts with lacquer.
Can C90700 BJ-S be formed, bent or molded?
Not cold formable — supplied as sand, chill, centrifugal or continuous castings, or gas-atomised powder for LPBF/binder jetting; pour 1150–1250 °C with good feeding to avoid inter-dendritic shrinkage porosity.
What is the maximum service temperature of C90700 BJ-S?
C90700 BJ-S 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 C90700-M01 and C90700-HT?
M01 is the default condition — use the standard sand cast gear-bronze condition for worm wheels, bushings and one-off castings to ASTM B427, giving 305 MPa tensile, 80 HB and 12 % elongation without further treatment. HT: use when maximum gear-tooth hardness and load capacity are required from a C90700 casting; ductility drops sharply. Yield strength is 152 MPa in M01 versus 250 MPa in HT.
Sources
- ASTM B427 — Gear Bronze Alloy Castings — ASTM International (2020)
- ASTM B505/B505M — Continuous Cast Copper Alloy Castings — ASTM International (2018)
- GB/T 1176 — (ZCuSn10P1) — SAC (2013)
- CDA Alloy Datasheet C90700 — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- CuSn10 bronze powder for LPBF — material datasheet — SLM Solutions / m4p / Sandvik Osprey (2023)
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.