Copper Alloy ZCuPb20Sn5-S (Sand cast)
Heat-treated state
UNS C94100 · EN CC497K
Choose for large or one-off bearing shells and complex housings where dimensional tolerance is loose.
Values for the S condition
Other ZCuPb20Sn5 tempers and conditions
ZCuPb20Sn5 is listed in 4 conditions; see the grade overview at ZCuPb20Sn5.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SThis page Sand cast | Choose for large or one-off bearing shells and complex housings where dimensional tolerance is loose. | 60 | 160 | 7 | 48 HB | 10.5 % IACS |
LaDefault Continuously cast bar / tube | Standard stock condition: continuously cast bar and tube for machined high-speed bearing bushings and thrust washers. | 65 | 175 | 9 | 55 HB | 11 % IACS |
Permanent (metal) mould cast | Choose for medium-volume small bushings needing finer grain, less lead segregation and better surface than sand casting. | 68 | 175 | 8 | 57 HB | 11 % IACS |
Centrifugally cast | Choose for large-diameter, thick-wall bearing sleeves and bimetal liners where a dense, inclusion-free bore is required. | 70 | 190 | 8 | 58 HB | 11 % IACS |
What is ZCuPb20Sn5-S?
ZCuPb20Sn5-S is ZCuPb20Sn5 heat treated to S — choose for large or one-off bearing shells and complex housings where dimensional tolerance is loose. ZCuPb20Sn5-S has a yield strength of 60 MPa (8.7 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 100% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 70 GPa (10.2 Msi). ZCuPb20Sn5-S has a density of 9.35 g/cm³ (0.338 lb/in³), heavier than 100% of copper alloy grades. It melts at 760°C (1,400 °F). La is the default condition FabDigit quotes; S is available on request or by drawing note.
Advantages
- Easy to machine — 90/100, better than 98% of copper alloy grades
Limitations
- Low strength — 60 MPa (8.7 ksi), worse than 100% of copper alloy grades
- Low stiffness — 70 GPa (10.2 Msi), worse than 100% of copper alloy grades
- Needs corrosion protection — 43/100, worse than 99% of copper alloy grades
- Difficult to weld — 10/100, worse than 98% of copper alloy grades
- Limited formability — 5/100, worse than 98% of copper alloy grades
ZCuPb20Sn5-S properties
Typical room-temperature values for ZCuPb20Sn5-S; 19 are specific to this condition. Other listed values are ZCuPb20Sn5 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
ZCuPb20Sn5-S has a density of 9.35 g/cm³ (0.338 lb/in³), heavier than 100% of copper alloy grades. It melts at 760°C (1,400 °F).
Mechanical12
ZCuPb20Sn5-S has a yield strength of 60 MPa (8.7 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 100% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZCuPb20Sn5-S is rated for continuous service to 200°C (392 °F). It conducts heat at 57 W/m·K (32.9 BTU/hr·ft·°F), worse than 64% of copper alloy grades. Thermal expansion is 18.5 µm/m·K (10.3 µin/in·°F).
Electrical3
ZCuPb20Sn5-S conducts electricity at 10.5 % IACS, worse than 72% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (43/100), worse than 99% of copper alloy grades.
Sustainability4
Producing a kilogram of ZCuPb20Sn5-S takes about 58 MJ of energy and emits 3.6 kg of CO₂ — more than 61% of copper alloy grades. Typical recycled content is 60%.
Manufacturability8
ZCuPb20Sn5-S's machinability is excellent (90/100, better than 98% of copper alloy grades); weldability not recommended (10/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZCuPb20Sn5-S
Is ZCuPb20Sn5 easy to machine?
Free-cutting: use sharp positive-rake tools, high speed, light feed and flood coolant; chips are short and lead dust requires extraction — avoid excessive burnishing of the soft bore.
Can ZCuPb20Sn5 be welded?
Not practically weldable — lead causes hot cracking and porosity; join by mechanical press-fit, sintering to a steel backing, or soft soldering only.
Can ZCuPb20Sn5 be formed, bent or molded?
Casting-only alloy (sand, metal mould, continuous or centrifugal); pour with controlled cooling and stirring/chill to keep lead finely dispersed and avoid gravity segregation in thick sections.
What surface finishes work on ZCuPb20Sn5?
Bore honed or diamond-burnished for bearing surfaces; can be tin- or silver-plated for anti-fretting, but not anodized; chemical blackening possible.
ZCuPb20Sn5 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 |
|---|---|---|
| Sn | 4 – 6 | 5 |
| Pbfree lead phase provides lubricity/embeddability | 18 – 23 | 20 |
| Znimpurity limit | ≤ 2 | — |
| Feimpurity limit | ≤ 0.25 | — |
| Sbimpurity limit | ≤ 0.75 | — |
| Pimpurity limit | ≤ 0.1 | — |
| Cu≈74–78 %; total impurities ≤1.0 % per GB/T 1176 | balance | — |
ZCuPb20Sn5-S — frequently asked
What is ZCuPb20Sn5-S used for?
ZCuPb20Sn5-S is typically used for crankshaft bearings, high-speed journal bearings and connecting rod bushings. In short: highest-lead journal bronze; best anti-seizure bearing grade; lowest strength in family.
What is the yield strength of ZCuPb20Sn5-S?
ZCuPb20Sn5-S has a typical yield strength of 60 MPa (8.7 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 100% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is ZCuPb20Sn5-S easy to machine?
Yes — machinability is rated excellent (90/100, better than 98% of copper alloy grades). Free-cutting: use sharp positive-rake tools, high speed, light feed and flood coolant; chips are short and lead dust requires extraction — avoid excessive burnishing of the soft bore.
Can ZCuPb20Sn5-S be welded?
Not readily — weldability is rated not recommended (10/100). Not practically weldable — lead causes hot cracking and porosity; join by mechanical press-fit, sintering to a steel backing, or soft soldering only.
What surface finishes work on ZCuPb20Sn5-S?
Bore honed or diamond-burnished for bearing surfaces; can be tin- or silver-plated for anti-fretting, but not anodized; chemical blackening possible.
Can ZCuPb20Sn5-S be formed, bent or molded?
Casting-only alloy (sand, metal mould, continuous or centrifugal); pour with controlled cooling and stirring/chill to keep lead finely dispersed and avoid gravity segregation in thick sections.
What is the maximum service temperature of ZCuPb20Sn5-S?
ZCuPb20Sn5-S 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 ZCuPb20Sn5-La and ZCuPb20Sn5-S?
La is the default condition — standard stock condition: continuously cast bar and tube for machined high-speed bearing bushings and thrust washers. S: choose for large or one-off bearing shells and complex housings where dimensional tolerance is loose. Yield strength is 65 MPa in La versus 60 MPa in S.
Sources
- EN 1982 Copper and copper alloys — Ingots and castings (CC497K CuPb20Sn5-C) — CEN (2017)
- ASTM B505/B505M Continuous-Cast Copper Alloys (C94100) — ASTM (2018)
- CDA alloy datasheet C94100 — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties of Cast Copper Alloys — ASM International (1990)
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.