PTFE-Bronze40 BZ40
Additive grade · default condition
BZ40 = pTFE + 40 wt% bronze
Standard bronze-filled bearing/seal compound: best balance of load capacity, wear life and machinability.
Values for the BZ40 condition
Other PTFE-Bronze40 grades and fills
PTFE-Bronze40 is listed in 4 conditions; see the grade overview at PTFE-Bronze40.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
PTFE + bronze + graphite (typ. 40% bronze / 5% graphite) | Choose for high sliding speed and water/steam service where a lower friction coefficient than plain bronze-filled is needed. | 10 | 13 | 120 | 63 Shore D |
PTFE + 55% bronze + 5% molybdenum disulphide | Use where dry-running start-up friction and stick-slip must be minimised on steel counterfaces. | 10 | 12 | 90 | 68 Shore D |
BZ40DefaultThis page PTFE + 40 wt% bronze | Standard bronze-filled bearing/seal compound: best balance of load capacity, wear life and machinability. | 11 | 16 | 150 | 65 Shore D |
PTFE + 60 wt% bronze | Pick for maximum PV, minimum creep and best heat removal in hydraulic piston rings and heavy-duty bushings. | — | 13 | 100 | 68 Shore D |
What is PTFE-Bronze40 BZ40?
PTFE-Bronze40 BZ40 is PTFE-Bronze40 in the BZ40 grade — standard bronze-filled bearing/seal compound: best balance of load capacity, wear life and machinability. PTFE-Bronze40 BZ40 has a yield strength of 11 MPa (1.6 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 89% of polymer grades. Elongation at break is 150% and the elastic modulus is 1.1 GPa (0.16 Msi). PTFE-Bronze40 BZ40 has a density of 3.1 g/cm³ (0.112 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is -97°C (-143 °F).
Advantages
- Conducts heat well — 0.45 W/m·K (0.26 BTU/hr·ft·°F), better than 97% of polymer grades
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- High service temperature — 250°C (482 °F), better than 94% of polymer grades
- Low moisture uptake — 0.04%, better than 86% of polymer grades
Limitations
- Heavy — 3.1 g/cm³ (0.112 lb/in³), worse than 100% of polymer grades
- Low strength — 11 MPa (1.6 ksi), worse than 89% of polymer grades
- Difficult to weld — 5/100, worse than 89% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
- Hard to polish — 30/100, worse than 82% of polymer grades
PTFE-Bronze40 BZ40 properties
Typical room-temperature values for PTFE-Bronze40 BZ40; 26 are specific to this condition. Other listed values are PTFE-Bronze40 reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
PTFE-Bronze40 BZ40 has a density of 3.1 g/cm³ (0.112 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is -97°C (-143 °F).
Mechanical15
PTFE-Bronze40 BZ40 has a yield strength of 11 MPa (1.6 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 89% of polymer grades. Elongation at break is 150% and the elastic modulus is 1.1 GPa (0.16 Msi).
Thermal10
PTFE-Bronze40 BZ40 is rated for continuous service to 250°C (482 °F). It conducts heat at 0.45 W/m·K (0.26 BTU/hr·ft·°F), better than 97% of polymer grades. Thermal expansion is 90 µm/m·K (50 µin/in·°F).
Electrical2
PTFE-Bronze40 BZ40 has an electrical resistivity of 10,000 Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 78% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of PTFE-Bronze40 BZ40 takes about 145 MJ of energy and emits 7 kg of CO₂ — more than 83% of polymer grades. Typical recycled content is 0%.
Manufacturability6
PTFE-Bronze40 BZ40's machinability is very good (70/100, better than 74% of polymer grades); weldability not recommended (5/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PTFE-Bronze40 BZ40
Is PTFE-Bronze40 easy to machine?
Turns and mills easily with very sharp, positive-rake carbide or PCD tools; the bronze filler is abrasive so HSS dulls fast — use high speed, light cuts, and support thin walls against cold flow and thermal growth.
Can PTFE-Bronze40 be welded?
Not weldable or solvent-bondable; joints must be mechanical (clamped, retained rings) or use etched-surface adhesive bonding with sodium-naphthalene/plasma treatment.
Can PTFE-Bronze40 be formed, bent or molded?
Not melt-processable — cold-pressed and free-sintered at ~370–380 °C with slow cooling; ram extrusion is used for rod/tube, and rings are skived or moulded to near-net shape.
What surface finishes work on PTFE-Bronze40?
No plating or painting; finish by fine turning/burnishing, and run in against a hard (≥45 HRC) counterface polished to Ra 0.2–0.4 µm to build the transfer film.
PTFE-Bronze40 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 |
|---|---|---|
| bronze powder (CuSn10 / CuSn10Zn)atomised or irregular bronze; ~15 vol% of the compound | 38 – 42 | 40 |
| PTFE (polytetrafluoroethylene)suspension-polymerised moulding powder | ≥ 58 (balance) | — |
PTFE-Bronze40 BZ40 — frequently asked
What is PTFE-Bronze40 BZ40 used for?
PTFE-Bronze40 BZ40 is typically used for high-load thrust washers and bearings, hydraulic rod/piston seals, wear rings in hydraulic cylinders and guide rings. In short: highest load-capacity PTFE; most thermally conductive PTFE; abrasive; needs carbide tooling.
What is the yield strength of PTFE-Bronze40 BZ40?
PTFE-Bronze40 BZ40 has a typical yield strength of 11 MPa (1.6 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 89% of polymer grades. Strength varies by condition: see the 4 listed tempers.
Is PTFE-Bronze40 BZ40 easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Turns and mills easily with very sharp, positive-rake carbide or PCD tools; the bronze filler is abrasive so HSS dulls fast — use high speed, light cuts, and support thin walls against cold flow and thermal growth.
Can PTFE-Bronze40 BZ40 be welded?
Not readily — weldability is rated not recommended (5/100). Not weldable or solvent-bondable; joints must be mechanical (clamped, retained rings) or use etched-surface adhesive bonding with sodium-naphthalene/plasma treatment.
What surface finishes work on PTFE-Bronze40 BZ40?
No plating or painting; finish by fine turning/burnishing, and run in against a hard (≥45 HRC) counterface polished to Ra 0.2–0.4 µm to build the transfer film.
Can PTFE-Bronze40 BZ40 be formed, bent or molded?
Not melt-processable — cold-pressed and free-sintered at ~370–380 °C with slow cooling; ram extrusion is used for rod/tube, and rings are skived or moulded to near-net shape.
What is the maximum service temperature of PTFE-Bronze40 BZ40?
PTFE-Bronze40 BZ40 is rated for continuous use to about 250°C (482 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between PTFE-Bronze40 BZ40 and PTFE-Bronze40 BZ-GR?
BZ40 is the default condition — standard bronze-filled bearing/seal compound: best balance of load capacity, wear life and machinability. BZ-GR: choose for high sliding speed and water/steam service where a lower friction coefficient than plain bronze-filled is needed. Yield strength is 11 MPa in BZ40 versus 10 MPa in BZ-GR.
Sources
- ASTM D4745 — Filled Compounds of PTFE Molding and Extrusion Materials — ASTM International (2021)
- ASTM D4894 / D4895 — PTFE Molding and Extrusion Materials — ASTM International (2022)
- TECAFLON PTFE filled compounds (bronze, glass, carbon) — Ensinger (2023)
- Filled PTFE compound property tables — Fluorocarbon / Zeus Industrial Products (2022)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
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.