Cast nylon (PA6 G) – natural, oil-filled and MoS₂-filled
Cast polyamide 6 for large rods and sheets, bushings, sheaves and gears
Cast nylon (polyamide 6 G, "nylon cast") is polymerized directly in the mold, which allows large rods and sheets with little internal stress. It is tough and resistant to wear and impact, and it replaces bronze and steel in bushings, sheaves, gears and guides. Oil-filled and MoS₂-filled grades reduce friction and work better without lubrication. Like all nylons, it absorbs water and changes dimensions in humid environments.
Designations and equivalents
| System | Designation |
|---|---|
| Abbreviation (ISO 1043) | PA6 G (nylon cast) |
| Trade names | TECAST T (Ensinger); Ertalon 6 PLA (MCAM); TECAST L (Ensinger); Nylatron LIG (MCAM, USA); Nylatron GSM (MCAM); TECAST T MO black (Ensinger) |
Standards by product form
| Form | Standard |
|---|---|
| Cast rod, sheet and tube | Manufacturer's specification (Ertalon 6 PLA, Nylatron, TECAST, Nylotec) |
| Food contact | FDA 21 CFR 177.1500 (natural grade) |
| Machined part to drawing | ISO 2768 tolerance or as per drawing |
Composition and filler
Nominal composition
| Component | Content |
|---|---|
| Polyamide 6 (cast) | ≈ 100% (natural) |
| Oil-filled grade | built-in lubricating oil |
| MoS₂-filled grade | molybdenum disulfide (≈ 1–2%)* |
Mechanical properties
Typical values from the stock-shape manufacturer's catalog, 23 °C (natural, oil-filled, MoS₂-filled); ISO/ASTM methods as per the source
| Property | Value |
|---|---|
| Tensile strength | natural: 83 MPa · oil-filled: 69 MPa · MoS₂-filled: 75.8 MPa |
| Modulus of elasticity (tensile) | natural: 3,500 MPa · oil-filled: 2,900 MPa · MoS₂-filled: 2,760 MPa |
| Elongation at break | natural: 40% · oil-filled: 50% · MoS₂-filled: 30% |
| Compressive strength | natural: 83 MPa · oil-filled: 76 MPa · MoS₂-filled: 96.5 MPa |
| Hardness | natural: Shore D 83 · oil-filled: Shore D 80 · MoS₂-filled: Shore D 85 |
| Notched impact | natural: 4 kJ/m² · oil-filled: 5 kJ/m² · MoS₂-filled: 26.7 J/m |
Typical physical and thermal properties
| Property | Value |
|---|---|
| Density | natural: 1.15 g/cm³ · oil-filled: 1.13 g/cm³ · MoS₂-filled: 1.16 g/cm³ |
| Maximum continuous service temperature | natural: 100 °C · oil-filled: 100 °C · MoS₂-filled: 93.3 °C |
| Maximum short-term temperature | 170 °C |
| Minimum service temperature | natural: -30 °C · MoS₂-filled: -30 °C |
| HDT (1.8 MPa) | natural: 80 °C · oil-filled: 93.3 °C · MoS₂-filled: 93.3 °C |
| Melting point or glass transition | natural: 215 °C · oil-filled: 218 °C · MoS₂-filled: 216 °C |
| Linear thermal expansion | natural: 120 µm/m·K · oil-filled: 130 µm/m·K · MoS₂-filled: 90 µm/m·K |
| Thermal conductivity | natural: 0.38 W/m·K · oil-filled: 0.37 W/m·K · MoS₂-filled: 0.3 W/m·K |
| Water absorption (24 h) | natural: 0.2-0.4% · oil-filled: 0.2-0.4% · MoS₂-filled: 0.6% |
| Water absorption (saturation) | natural: 6.5% · oil-filled: 6% · MoS₂-filled: 7% |
| Dielectric strength | natural: 25 / 17 kV/mm · MoS₂-filled: 15.7 kV/mm |
| Flammability (UL 94) | HB |
Friction, wear and PV limit
| Property | Value |
|---|---|
| Dynamic coefficient of friction against steel | natural: 0.26 (dynamic, ASTM D3702, 40 psi (0.28 MPa), 50 ft/min (0.25 m/s)) · oil-filled: 0.14 (dynamic, dry against steel (MCAM QTM 55007)) · MoS₂-filled: 0.2 (dynamic, dry against steel (MCAM QTM 55007)) |
| PV limit (pressure × velocity) | oil-filled: 0.21 MPa·m/s (MCAM QTM 55007, dry against steel, safety factor 4:1 already applied; original 6,000 psi·ft/min) · MoS₂-filled: 0.105 MPa·m/s (MCAM QTM 55007, dry against steel, safety factor 4:1 already applied; original 3,000 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 | Limited: mineral acids attack polyamide |
| Bases (alkalis) | Limited |
| Solvents | Good; chlorinated solvents limited |
| Hydrocarbons and oils | Very good (hydraulic oil OK) |
| Steam and hot water | Limited |
Stock forms and sizes
- Rod (round bar)
- Sheet (plate)
- Tube and bushing
- Custom cast bushings
- 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 100 °C, short peaks up to 170 °C; minimum -30 °C (unloaded; under load, limited by HDT and creep). |
| Annealing (stress relief) | Stress-relief annealing of large parts before machining; condition to the service humidity when the tolerance is tight. |
| Bonding and welding | Does not weld well; bonding is possible with specific adhesives. |
| Machining | Machines very well; allow for swelling from moisture in bushing clearances. |
Typical applications
- Machine bushings and bearings
- Sheaves, pulleys and wheels
- Gears and crown wheels
- Guides and wear strips
- Wear plates and hammers for light crushing
Alternatives: UHMW for abrasion and humidity; POM for small precision parts; bronze-filled PTFE or PEEK for higher temperature.
Frequently asked questions
Which standards cover Cast nylon (PA6 G)?
Cast rod, sheet and tube: Manufacturer's specification (Ertalon 6 PLA, Nylatron, TECAST, Nylotec). Food contact: FDA 21 CFR 177.1500 (natural grade). Machined part to drawing: ISO 2768 tolerance or as per drawing.
Up to what temperature can Cast nylon (PA6 G) be used?
Continuous service up to 100 °C, short peaks up to 170 °C; minimum -30 °C (unloaded; under load, limited by HDT and creep).
Which materials can replace Cast nylon (PA6 G)?
UHMW for abrasion and humidity; POM for small precision parts; bronze-filled PTFE or PEEK for higher temperature.
Cast or extruded nylon?
Cast nylon (PA6 G) allows large parts and rods with less internal stress; extruded nylon (PA6 and PA66) is usual in smaller diameters.
Why did the nylon bushing seize on the shaft?
Most likely because of water absorption: nylon swells in humid environments. Calculate the clearance for the service humidity or switch to POM, PET or UHMW, which absorb almost no water.
Oil-filled or MoS₂-filled nylon?
The oil-filled grade has the lowest friction and suits bushings without lubrication; the MoS₂-filled grade improves wear and surface hardness and is common in gears and sheaves.
