Graphite-Filled PTFE Piston Ring — why this filler for this component
Graphite-filled rings are specified when the cylinder bore is soft, plated or otherwise easily scored. Graphite is the gentlest of the common fillers and gives the lowest friction of the filled grades, so the ring runs freely without abrading the wall it seals against.
Where Graphite-Filled PTFE Piston Ring is used
Against a carbon-filled ring
graphite protects a soft or plated bore and runs at lower friction, but carries less load. Carbon is the better answer on hardened bores at higher pressure; graphite is the better answer when protecting the cylinder matters more than maximum duty.
Wear is steady and the ring tends to degrade gracefully rather than suddenly. Blow-by trend remains the practical measure; a graphite ring will usually give warning across several service intervals.
Key properties
Compound
Graphite-Filled PTFE, typically around 15% graphite
How it works here
Graphite is itself a solid lubricant, so the ring establishes and maintains a transfer film with less initial wear than a harder-filled compound. In sustained dry running that shows as a lower and more stable friction coefficient, and correspondingly less heat generated at the contact.
Where it does not belong
Load capacity and creep resistance are lower than carbon- or bronze-filled grades. At high discharge pressure a graphite-filled ring will deform where a carbon-filled one would hold, so this is not the grade for the most heavily loaded stages.
Specifications
| Property | Value |
|---|---|
| Compound | Graphite-filled PTFE, typically around 15% graphite |
| Duty | Dry running against soft, plated or worn bores |
| Form supplied | Machined to cylinder drawing |
| Governing factor | Low friction and protection of the cylinder wall |
| Counterface | Suits softer and non-ideal bore finishes |
| Not suitable for | Highest-pressure stages — specify carbon-filled instead |
Manufacturing process
Compression moulded from around 15% graphite 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
Graphite is itself a solid lubricant, so the ring establishes and maintains a transfer film with less initial wear than a harder-filled compound. In sustained dry running that shows as a lower and more stable friction coefficient, and correspondingly less heat generated at the contact.
How to specify your order
Against a carbon-filled ring: graphite protects a soft or plated bore and runs at lower friction, but carries less load. Carbon is the better answer on hardened bores at higher pressure; graphite is the better answer when protecting the cylinder matters more than maximum duty.
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
Ring gap is set hot, as with any PTFE compound. Because graphite is forgiving of the counterface, it is often the right retrofit choice for an older compressor whose bore is no longer in as-new condition.
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
Wear is steady and the ring tends to degrade gracefully rather than suddenly. Blow-by trend remains the practical measure; a graphite ring will usually give warning across several service intervals.
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 Graphite-Filled PTFE Piston Ring options does HEMSUN manufacture?
Graphite-filled rings are specified when the cylinder bore is soft, plated or otherwise easily scored. Graphite is the gentlest of the common fillers and gives the lowest friction of the filled grades, so the ring runs…
Can you supply Graphite-Filled PTFE Piston Ring 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 Graphite-Filled PTFE Piston Ring?
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.
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