PEEK Annealed
Temper
ASTM D6402, F2026 · also APTIV, KetaSpire
Specify after printing or heavy machining to raise crystallinity, restore heat resistance and prevent dimensional drift in service.
Values for the Annealed condition
Other PEEK grades and fills
PEEK is listed in 10 conditions; see the grade overview at PEEK.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
FDM/FFF 3D-printed PEEK, as printed (no post-anneal) | Use for prototypes and low-load fixtures; expect anisotropy, partial crystallinity and Z-direction strength far below molded PEEK. | — | 85 | 10 | — |
10% PTFE lubricated | Pick for low-friction sliding parts that must stay electrically insulating and reasonably tough (no fiber reinforcement). | — | 90 | 15 | 83 Shore D |
Standard injection-molding grade (medium viscosity, unfilled) | Default choice for general injection-molded PEEK parts where flow and toughness are balanced. | 100 | 100 | 40 | 85 Shore D |
AnnealedThis page Annealed / stress-relieved (printed or machined parts, ~200–300 °C soak) | Specify after printing or heavy machining to raise crystallinity, restore heat resistance and prevent dimensional drift in service. | 100 | 95 | 12 | 87 Shore D |
ESD / static-dissipative PEEK | Pick for semiconductor wafer handling, test sockets and fuel-system parts where charge build-up must be bled off. | — | 110 | 4 | 88 Shore D |
Bearing / tribological grade (≈10% PTFE + 10% graphite + 10% carbon fiber, Victrex 450FC30 / TECAPEEK TF10 class) | Pick for dry-running bushings, wear rings, seals and thrust washers needing low friction and low wear rate at high PV. | — | 125 | 2.5 | — |
20% Glass Fiber | PEEK compounded with 20% short glass fiber — higher stiffness, strength and creep resistance than unfilled PEEK with HDT near the melting point, at the cost of ductility and impact. | — | 140 | 3 | 87 Shore D |
10% carbon-fiber reinforced | Pick when moderate stiffness gain and dimensional stability are wanted while keeping some ductility and machinability. | — | 145 | 5 | — |
30% glass-fiber reinforced | Pick for high stiffness and creep resistance at 200–260 °C when electrical insulation must be retained. | 165 | 165 | 2.5 | 105 HRM |
30% carbon-fiber reinforced | Pick for highest strength/stiffness-to-weight, low CTE, better heat dissipation and static-dissipative behaviour. | 225 | 225 | 1.8 | 107 HRM |
What is PEEK Annealed?
PEEK Annealed is PEEK in the Annealed temper — specify after printing or heavy machining to raise crystallinity, restore heat resistance and prevent dimensional drift in service. PEEK Annealed has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 95% of polymer grades. Elongation at break is 12% and the elastic modulus is 3.9 GPa (0.566 Msi). PEEK Annealed has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 143°C (289 °F).
Advantages
- High strength — 100 MPa (14.5 ksi), better than 95% of polymer grades
- High service temperature — 250°C (482 °F), better than 94% of polymer grades
- Good corrosion resistance — 91/100, better than 87% of polymer grades
- Stiff — 3.9 GPa (0.566 Msi), better than 86% of polymer grades
- Conducts heat well — 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 77% of polymer grades
Limitations
- High embodied carbon — 15 kg CO₂/kg, worse than 96% of polymer grades
PEEK Annealed properties
Typical room-temperature values for PEEK Annealed; 24 are specific to this condition. Other listed values are PEEK reference data and may not represent this condition. Bars are the position among polymer grades.
Physical5
PEEK Annealed has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 143°C (289 °F).
Mechanical17
PEEK Annealed has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 95% of polymer grades. Elongation at break is 12% and the elastic modulus is 3.9 GPa (0.566 Msi).
Thermal11
PEEK Annealed is rated for continuous service to 250°C (482 °F). It conducts heat at 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 77% of polymer grades. Thermal expansion is 47 µm/m·K (26.1 µin/in·°F).
Electrical7
PEEK Annealed is an electrical insulator with a dielectric strength of 21 kV/mm (533.4 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (91/100), better than 87% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PEEK Annealed takes about 290 MJ of energy and emits 15 kg of CO₂ — more than 95% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PEEK Annealed's machinability is very good (70/100, better than 74% of polymer grades); weldability fair (45/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PEEK Annealed
Is PEEK easy to machine?
Machines cleanly with sharp carbide (polished flutes, positive rake) and air/flood cooling; glass- and carbon-filled grades are abrasive and want diamond-coated tooling, and thick machined parts should be annealed before finish cuts to avoid stress cracking.
Can PEEK be welded?
Joins by ultrasonic, laser, hot-plate, spin and infrared welding at 380–400 °C interface temperature; no solvent bonding — adhesive joints need plasma or abrasive surface activation.
Can PEEK be formed, bent or molded?
Inject at 360–400 °C melt with 170–200 °C mold for full crystallinity; resin must be dried (150 °C, 3 h), runners/gates generous, and slow crystallising thin sections may need post-mold annealing.
What surface finishes work on PEEK?
Can be machined-to-finish, bead-blasted, laser-marked or plasma treated for printing/metallising; not paintable without primer and not anodizable — parts are usually left natural tan or supplied in black.
PEEK 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 |
|---|---|---|
| glass fiberGF variants only (chopped E-glass, sized for PAEK) | 10 – 40 | 30 |
| carbon fiberCF variants only (PAN-based chopped fiber) | 10 – 40 | 30 |
| PTFEbearing / lubricated variants | 5 – 15 | 10 |
| graphitebearing variants | 5 – 10 | 10 |
| carbon blackblack / ESD variants | 1 – 15 | 3 |
| poly(oxy-1,4-phenylene-oxy-1,4-phenyleneUnfilled grade; polymerised from 4,4'-difluorobenzophenone + hydroquinone in diphenyl sulfone | balance | — |
PEEK Annealed — frequently asked
What is PEEK Annealed used for?
PEEK Annealed is typically used for spinal fusion implants, aerospace seals and back-up rings, downhole oil and gas seals, semiconductor wafer handling fixtures, bearings, bushings and wear pads and compressor valve plates. In short: ultra-performance plastic.
What is the yield strength of PEEK Annealed?
PEEK Annealed has a typical yield strength of 100 MPa (14.5 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 95% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is PEEK Annealed easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Machines cleanly with sharp carbide (polished flutes, positive rake) and air/flood cooling; glass- and carbon-filled grades are abrasive and want diamond-coated tooling, and thick machined parts should be annealed before finish cuts to avoid stress cracking.
Can PEEK Annealed be welded?
With care — weldability is rated fair (45/100). Joins by ultrasonic, laser, hot-plate, spin and infrared welding at 380–400 °C interface temperature; no solvent bonding — adhesive joints need plasma or abrasive surface activation.
What surface finishes work on PEEK Annealed?
Can be machined-to-finish, bead-blasted, laser-marked or plasma treated for printing/metallising; not paintable without primer and not anodizable — parts are usually left natural tan or supplied in black.
Can PEEK Annealed be formed, bent or molded?
Inject at 360–400 °C melt with 170–200 °C mold for full crystallinity; resin must be dried (150 °C, 3 h), runners/gates generous, and slow crystallising thin sections may need post-mold annealing.
What is the maximum service temperature of PEEK Annealed?
PEEK Annealed 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.
Can FabDigit make parts in PEEK Annealed?
Yes — PEEK Annealed is available for CNC machining, sheet metal, injection molding and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- VICTREX PEEK 450G / 450GL30 / 450CA30 / 450FC30 product datasheets — Victrex plc (2023)
- KetaSpire PEEK design & processing guide — Solvay Specialty Polymers (2022)
- TECAPEEK stock shape property tables — Ensinger GmbH (2023)
- CAMPUS plastics multipoint data for PEEK grades — CWFG / CAMPUS (2024)
- ASM Engineered Materials Handbook: Engineering Plastics — ASM International (1988)
- ISO 527 / ISO 178 / ISO 75 / ISO 180 test methods; ASTM D638, D790, D648 — ISO / ASTM (2019)
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.