PA6 (Nylon 6)
An engineering polyamide (nylon)
Typical values for the temper in the title
PA6 (nylon 6) is one of the most common engineering plastics in the world. It is tough, impact and wear resistant, and resistant to oils and fuels. In cast form (cast nylon) it is sold as large rods and plates for machining.
Its main drawback is high water absorption, which changes dimensions and properties. It is used for gears, pulleys and bushings, automotive parts, power-tool housings and machine parts.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 75–80 MPa | |
| Elongation A | 30–50% | |
| Modulus of elasticity E | 2.7–2.9 GPa | |
| Density ρ | 1.14 g/cm³ | |
| Max continuous service temperature | 100–120°C | |
| Heat deflection temperature (HDT) | 180°C (GF30) | |
| Machinability | 75% | relative rating in the site database |
Structure and family
| Feature | Value | Meaning |
|---|---|---|
| Type | semi-crystalline polyamide | strength and toughness |
| Tm melting | about 220 °C | |
| Water absorption | high (the highest of common polyamides, together with PA66) | affects dimensions and properties |
Typical values per producer data sheets.
Grades and versions
In engineering polymers, the choice is between an unfilled grade, filled grades (glass or carbon fiber) and special grades (bearing, medical, food). Filler strongly changes strength, stiffness and expansion.
| Version | Properties | When to choose it |
|---|---|---|
| Unfilled | tough and ductile | general parts |
| Glass-fiber filled (GF30) | much stronger and stiffer, less dimensional change | structural and automotive parts |
| Cast nylon | large rods and plates, high crystallinity | large machined parts |
Applications
- Gears and pulleys
- Bushings and bearings
- Automotive parts
- Power-tool housings
- Machine parts
Fabrication
Water absorption
Polyamides absorb water from the air. Water plasticizes the material, reduces strength and stiffness and increases dimensions. For a precision part, design to the conditioned state, not the dry state.
Machining
Use very sharp tools, a feed that does not overheat the material, and good support (the material is flexible and deforms under clamping). For precision parts, stress-relief annealing before final machining is sometimes performed.
Joining
Ultrasonic, hot-plate or vibration welding, and mechanical assembly.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| PA66 (Nylon 66) | 70-85 MPa | Ultrasonic | PA66: more heat resistant, slightly harder · material page |
| PA12 (Nylon 12) | 50 MPa | Laser/Ultrasonic | PA12: absorbs little water, flexible · material page |
| POM (Acetal) | 70 MPa | Ultrasonic | POM: dimensionally stable, absorbs little water · material page |
Common mistakes
Designing to dry-state properties
Conditioned, strength and stiffness are lower. Design to conditioned data.
Ignoring dimensional change
The part grows slightly as it absorbs water.
Choosing PA6 for a precision part in a humid environment
Water absorption changes dimensions. POM is more stable.
Equivalents, standards and supply
| ISO | PA6 |
|---|---|
| ASTM | D6779 |
| Standards | ASTM D6779 / ASTM D4066 |
| Forms | plate · rod · pellets |
| Producers | BASF Ultramid · Lanxess · DSM Akulon |
Learn more
Values are typical for an unfilled grade (unless stated otherwise) and for comparison only. In polymers, properties depend on grade, filler, temperature, moisture and load duration. For design, rely on the producer data sheet for the specific grade. Sources: ASTM classification standards (D8033, D5205, D5204, D6394, D4067 and others), producer data sheets, and the METAL HUB materials database.
Updated: October 31, 2026