3021 FR
Flame-retardant grade
FR = flame-retardant paper-phenolic laminate
Pick when the part sits inside enclosures that must meet UL 94 V-0 / FR-2-class flammability.
Values for the FR condition
What is 3021 FR?
3021 FR is 3021 in the FR grade — pick when the part sits inside enclosures that must meet UL 94 V-0 / FR-2-class flammability. 3021 FR has a tensile strength of 90 MPa (13.1 ksi), weaker than 72% of composite grades. Elongation at break is 1.5% and the elastic modulus is 8 GPa (1.16 Msi). 3021 FR has a density of 1.4 g/cm³ (0.0506 lb/in³), lighter than 64% of composite grades. Its glass-transition temperature is 150°C (302 °F).
Advantages
- Low embodied carbon — 3 kg CO₂/kg, better than 96% of composite grades
- Easy to machine — 80/100, better than 85% of composite grades
Limitations
- Limited service temperature — 110°C (230 °F), worse than 87% of composite grades
- Absorbs moisture — dry before molding — 1.5%, worse than 81% of composite grades
- Needs corrosion protection — 60/100, worse than 79% of composite grades
- Poor heat conductor — 0.25 W/m·K (0.144 BTU/hr·ft·°F), worse than 76% of composite grades
3021 FR properties
Typical room-temperature values for 3021 FR; 5 are specific to this condition. Other listed values are 3021 reference data and may not represent this condition. Bars are the position among composite grades.
Physical4
3021 FR has a density of 1.4 g/cm³ (0.0506 lb/in³), lighter than 64% of composite grades. Its glass-transition temperature is 150°C (302 °F).
Mechanical9
3021 FR has a tensile strength of 90 MPa (13.1 ksi), weaker than 72% of composite grades. Elongation at break is 1.5% and the elastic modulus is 8 GPa (1.16 Msi).
Thermal9
3021 FR is rated for continuous service to 110°C (230 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), worse than 76% of composite grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
3021 FR is an electrical insulator with a dielectric strength of 11 kV/mm (279.4 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 79% of composite grades. UV resistance is fair.
Sustainability2
Producing a kilogram of 3021 FR takes about 55 MJ of energy and emits 3 kg of CO₂ — less than 97% of composite grades.
Manufacturability2
3021 FR's machinability is very good (80/100, better than 85% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 3021 FR
Is 3021 easy to machine?
Machines like a hard thermoset — carbide or PCD tools, high speed/low feed, back it up when drilling to stop exit delamination, and extract the abrasive paper-phenolic dust.
Can 3021 be welded?
Thermoset: cannot be welded; join by bolting, riveting, or epoxy/phenolic adhesive after abrading the surface.
Can 3021 be formed, bent or molded?
Not thermoformable; 3021 is specifically the hot-punching grade — punch sheets ≤3 mm after preheating to ~90–120 °C for clean, crack-free blanks.
What surface finishes work on 3021?
Edges sand and deburr easily; seal cut edges with varnish or epoxy to limit moisture pickup, and expect no plating or anodising (paint/varnish only).
3021 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 |
|---|---|---|
| phenol-formaldehyde (resole) resinimpregnating matrix, may contain drying-oil or FR modifiers | 40 – 55 | 47 |
| pigment / filleriron-oxide (orange-red) or carbon black | 0 – 3 | 1 |
| cellulose kraft paperreinforcement plies; NOT glass fabric | ≥ 45 (balance) |
3021 FR — frequently asked
What is 3021 FR used for?
3021 FR is typically used for elevated-temperature electrical insulation, transformer and motor insulation parts and structural supports. In short: hot-punchable epoxy laminate; G-11 thermal class; 120 °C insulation grade.
What is the tensile strength of 3021 FR?
3021 FR has a typical tensile strength of 90 MPa (13.1 ksi) — weaker than 72% of composite grades.
Is 3021 FR easy to machine?
Yes — machinability is rated very good (80/100, better than 85% of composite grades). Machines like a hard thermoset — carbide or PCD tools, high speed/low feed, back it up when drilling to stop exit delamination, and extract the abrasive paper-phenolic dust.
Can 3021 FR be welded?
Thermoset: cannot be welded; join by bolting, riveting, or epoxy/phenolic adhesive after abrading the surface.
What surface finishes work on 3021 FR?
Edges sand and deburr easily; seal cut edges with varnish or epoxy to limit moisture pickup, and expect no plating or anodising (paint/varnish only).
Can 3021 FR be formed, bent or molded?
Not thermoformable; 3021 is specifically the hot-punching grade — punch sheets ≤3 mm after preheating to ~90–120 °C for clean, crack-free blanks.
What is the maximum service temperature of 3021 FR?
3021 FR is rated for continuous use to about 110°C (230 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- IEC 60893-3-4 Industrial rigid laminated sheets — Phenolic resin sheets (PF CP) — IEC (2013)
- ASTM D709 Standard Specification for Laminated Thermosetting Materials — ASTM (2017)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics (laminates section) — ASM International (1988)
- Paper-phenolic laminate (3021/XX/XPC) sheet datasheets — Chinese insulation-board producers ( / ) (2024)
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.