Bronze-Filled PTFE Seal — why this filler for this component
A bronze-filled seal is specified where the sealing element is also a wear element — a rod or piston seal running against a hard bore at pressure, where an unfilled lip would extrude and a softer grade would abrade away.
Where Bronze-Filled PTFE Seal is used
Against a glass-filled seal
bronze resists extrusion better and handles heat better, which suits high-pressure dynamic sealing. Glass-filled is the choice when the sealed medium is chemically aggressive, because it retains far more of PTFE’s resistance.
Leakage rises as the lip loses interference. Because the compound is stiff, a bronze-filled seal often holds tight until relatively late and then degrades quickly, so replacement is better planned on running hours than on observed weeping.
Key properties
Compound
Bronze-Filled PTFE, typically 40% bronze in 60% PTFE
How it works here
Bronze raises the extrusion resistance of the sealing lip and conducts heat away from the sliding contact. In a dynamic seal that combination matters: the lip stays dimensionally stable under pressure instead of being forced into the extrusion gap, and the contact does not run away thermally at speed.
Where it does not belong
The compound is not chemically inert and not clean. Bronze-filled seals belong in hydraulic and mechanical service; put one in an acid line, a steam line or a food process and the filler is attacked or contaminates the fluid.
Specifications
| Property | Value |
|---|---|
| Compound | Bronze-filled PTFE, typically 40% bronze |
| Duty | Dynamic sealing at pressure, hydraulic and mechanical service |
| Form supplied | Machined to seal drawing |
| Governing factor | Extrusion resistance and heat removal at the lip |
| Energising | Spring or elastomer energiser where the drawing specifies |
| Not suitable for | Acids, steam, oxidisers, food or pharmaceutical contact |
Manufacturing process
Compression moulded from 40% bronze in 60% PTFE compound, sintered, then machined to your drawing. Filled compounds need higher compaction pressure than unfilled PTFE to reach full density through the section.
Material selection notes
Bronze raises the extrusion resistance of the sealing lip and conducts heat away from the sliding contact. In a dynamic seal that combination matters: the lip stays dimensionally stable under pressure instead of being forced into the extrusion gap, and the contact does not run away thermally at speed.
How to specify your order
Against a glass-filled seal: bronze resists extrusion better and handles heat better, which suits high-pressure dynamic sealing. Glass-filled is the choice when the sealed medium is chemically aggressive, because it retains far more of PTFE’s resistance.
Quality checks and inspection
Dimensions are verified on CMM against your drawing. Filler content and sintered density are checked per ASTM D792, with tensile and elongation per ASTM D4894. A mill test certificate stating the lot, filler content and measured values ships with the order.
Ordering and export documentation
Check the extrusion gap as well as the seal dimensions. A bronze-filled lip tolerates a larger gap than unfilled PTFE, but the gap still governs whether the seal survives at pressure. Mating surface finish should follow the seal drawing.
Export packing and lead time
HEMSUN is a DGFT IEC registered exporter (Government of India). Commercial invoice, packing list and certificate of origin accompany international despatch.
Storage and handling
Leakage rises as the lip loses interference. Because the compound is stiff, a bronze-filled seal often holds tight until relatively late and then degrades quickly, so replacement is better planned on running hours than on observed weeping.
Compliance & Standards
HEMSUN is a DGFT IEC registered exporter (Government of India). Filler content and sintered density are verified per ASTM D792 on each batch, with tensile and elongation checked per ASTM D4894.
Frequently Asked Questions
What Bronze-Filled PTFE Seal options does HEMSUN manufacture?
A bronze-filled seal is specified where the sealing element is also a wear element — a rod or piston seal running against a hard bore at pressure, where an unfilled lip would extrude and a softer grade would abrade away.
Can you supply Bronze-Filled PTFE Seal for OEM and export orders?
Yes. We support prototype lots, recurring OEM programmes, and export packing with material certificates and dimensional inspection reports on request. Typical RFQ response is within one business day when drawings are complete.
How do I request a quote for Bronze-Filled PTFE Seal?
Send material grade, dimensions or drawing, quantity, application media, and operating temperature/pressure via https://hemsun.com/contact. Our engineering team confirms manufacturability, lead time, and pricing.
