PEEK – polyether ether ketone
High-performance thermoplastic: mechanical, chemical and thermal resistance up to 260 °C
PEEK is the highest-performing semi-crystalline thermoplastic in common use: it keeps strength and stiffness up to about 260 °C in continuous service, resists almost all chemicals (except concentrated sulfuric acid), steam and hydrolysis, and has low creep. It replaces metal in pump, valve and compressor parts, in food contact and in medical equipment.
Designations and equivalents
| System | Designation |
|---|---|
| Abbreviation (ISO 1043) | PEEK |
| Trade names | TECAPEEK natural (Ensinger); Ketron 1000 PEEK (MCAM); Victrex PEEK 450G / KetaSpire KT-820 (resins) |
Standards by product form
| Form | Standard |
|---|---|
| Rod, sheet and tube | Stock-shape manufacturer's specification (Victrex 450G, KetaSpire or equivalent resin) |
| Food contact | FDA 21 CFR 177.2415; EU 10/2011 (natural grade) |
| Machined part to drawing | ISO 2768 tolerance or as per drawing |
Composition and filler
Pure polymer, unfilled (natural grade)
| Component | Content |
|---|---|
| PEEK (polyether ether ketone) | 100% |
| Filler | none (natural) |
Mechanical properties
Typical values from the stock-shape manufacturer's catalog, 23 °C; ISO/ASTM methods as per the source
| Property | Value |
|---|---|
| Tensile strength | 116 MPa |
| Modulus of elasticity (tensile) | 4,200 MPa |
| Elongation at break | 15% |
| Compressive strength | 102 MPa |
| Hardness | Shore D 89 |
| Notched impact | 4 kJ/m² |
Typical physical and thermal properties
| Property | Value |
|---|---|
| Density | 1.31 g/cm³ |
| Maximum continuous service temperature | 260 °C |
| Maximum short-term temperature | 300 °C |
| Minimum service temperature | -50 °C |
| HDT (1.8 MPa) | 162 °C |
| Melting point or glass transition | 341 °C |
| Linear thermal expansion | 50 µm/m·K |
| Thermal conductivity | 0.27 W/m·K |
| Water absorption (24 h) | 0.02 / 0.03% |
| Water absorption (saturation) | 0.45% |
| Dielectric strength | 73 kV/mm |
| Flammability (UL 94) | V-0 |
Calculate the weight of PEEK – polyether ether ketone bar, plate or pipe →
Friction, wear and PV limit
| Property | Value |
|---|---|
| Dynamic coefficient of friction against steel | 0.25 (dynamic, ASTM D3702, 40 psi (0.28 MPa), 50 ft/min (0.25 m/s)) |
| PV limit (pressure × velocity) | 0.298 MPa·m/s (MCAM QTM 55007, dry against steel, safety factor 4:1 already applied; original 8,500 psi·ft/min); 2.42 MPa·m/s (ASTM D3702 (Ensinger USA), no safety factor stated; original 69,000 psi·ft/min) |
PV and friction depend on the test method, the mating surface (steel, stainless, roughness), lubrication and each manufacturer's safety factor: compare values from the same source and confirm by testing in critical applications.
Chemical resistance
| Medium | Resistance |
|---|---|
| Acids | Good; limited in strong acids (e.g. concentrated sulfuric/nitric) |
| Bases (alkalis) | Very good |
| Solvents | Very good |
| Hydrocarbons and oils | Very good |
| Steam and hot water | Excellent (resistant to hydrolysis and superheated steam) |
Stock forms and sizes
- Rod (round bar)
- Sheet (plate)
- Tube and bushing
- Custom profiles
- Raw material: rod (round bar), sheet (plate) and tube, cut to size
- Machined part to drawing or sample, in the same order as the metal parts
- Lot certificate of conformity; FDA/EU 10/2011 declaration when the grade allows
Service temperature, machining and assembly
| Item | Usual practice |
|---|---|
| Service temperature | Continuous service up to 260 °C, short peaks up to 300 °C; minimum -50 °C (unloaded; under load, limited by HDT and creep). |
| Annealing (stress relief) | Annealing (stress relief) recommended before precision machining of thick parts, as specified by the stock-shape manufacturer. |
| Bonding and welding | Can be welded by ultrasonic, hot plate or laser; bonded with epoxy or cyanoacrylate adhesive after surface preparation. |
| Machining | Machines very well to tight tolerances; carbide tooling, air cooling or chlorine-free coolant. |
Typical applications
- Pump and compressor rings and bushings
- High-pressure, high-temperature valve seats
- Parts exposed to steam and sterilization
- Gears and engineering bearings
- Insulators and connectors
- Parts for the food and pharmaceutical industries
Alternatives: Carbon-fiber or bearing-grade PEEK for higher wear and load; PTFE when only chemical resistance and friction matter; PPS or PEI when the temperature is lower and cost matters.
Frequently asked questions
Which standards cover PEEK?
Rod, sheet and tube: Stock-shape manufacturer's specification (Victrex 450G, KetaSpire or equivalent resin). Food contact: FDA 21 CFR 177.2415; EU 10/2011 (natural grade). Machined part to drawing: ISO 2768 tolerance or as per drawing.
Up to what temperature can PEEK be used?
Continuous service up to 260 °C, short peaks up to 300 °C; minimum -50 °C (unloaded; under load, limited by HDT and creep).
Which materials can replace PEEK?
Carbon-fiber or bearing-grade PEEK for higher wear and load; PTFE when only chemical resistance and friction matter; PPS or PEI when the temperature is lower and cost matters.
Can PEEK replace metal?
In many parts, yes: its tensile strength approaches that of light alloys, its density is 1.3 g/cm³ and it does not corrode. Assess load, temperature and creep before switching.
Up to what temperature does PEEK work?
About 260 °C in continuous service and up to 300 °C for short periods, according to the manufacturer. The glass transition is around 143 °C: above it, stiffness drops.
Is PEEK approved for food contact?
The natural grade complies with FDA (21 CFR 177.2415) and EU 10/2011. Ask for the lot declaration.
