Black Nylon PA66 Plastic Flat Washers: Non-Metallic Protection Experts in Fastening Systems
The core competitiveness of black nylon PA66 plastic flat washers lies in the exceptional performance of their base material. PA66 (polyhexamethylene adipamide), a high-strength engineering plastic, is modified with carbon black to form black products. This modification not only retains the inherent mechanical properties of nylon but also significantly enhances weather resistance and UV resistance. With a tensile strength of 60–80 MPa and a Shore D hardness of 80–85, these washers resist deformation under bolt clamping pressure, stably distributing loads across the substrate surface.
Compared to metal flat washers, these plastic washers offer multiple advantages:
- Excellent Insulation: With a volume resistivity exceeding 10¹⁴ Ω·cm, they effectively block current conduction, reducing short-circuit risks in electrical connections.
- Strong Chemical Stability: They tolerate greases, weak acids, and alkalis without electrochemical corrosion, unlike metal washers.
- Moderate Friction Coefficient (0.3–0.4): Ensures tight contact with fasteners while providing damping in vibrating environments.
- Lightweight: At 1/7 the weight of equivalent steel washers, they reduce overall fastening system weight, ideal for lightweight design requirements.
Key Technical Parameters and Selection Criteria
To ensure compatibility with fastening systems, focus on core technical parameters when selecting black nylon PA66 flat washers:
- Thickness: Ranges from 0.5–3 mm. Thin washers (0.5–1 mm) suit precision instrument gap adjustment; thick washers (2–3 mm) are for heavy load distribution.
- Inner Diameter Tolerance: Use H11-class tolerance to match bolt specifications, ensuring smooth bolt passage without excessive clearance-induced uneven loading.
Flatness is critical for protection—high-quality washers maintain a flatness error ≤ 0.1 mm/100 mm for uniform contact with connected surfaces. Edges must be smooth with no burrs and a fillet radius ≥ 0.3 mm to avoid 划伤 (scratches) to substrates or operators. For special environments, verify temperature resistance (-40°C to 120°C), aging resistance (no significant embrittlement after 5 years of outdoor exposure), and request material certification reports if needed.
Core Functions and Application Scenarios
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Load Distribution: These washers evenly transmit bolt clamping pressure across connected surfaces, converting concentrated loads from bolt heads into large-area uniform loads. This protects fragile substrates like wood, plastic, and thin metal sheets from crushing—effective in furniture assembly and plastic component connections.
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Electrical Insulation: An irreplaceable function in high/low-voltage equipment, distribution boxes, and motor terminals. They isolate metal fasteners from conductive substrates, preventing safety hazards from accidental conduction, even in 95% humidity environments.
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Anti-Loosening and Sealing: Nylon’s elastic deformation compensates for bolt loosening, providing continuous preload under vibration. Used with lock nuts, they improve anti-loosening performance by over 40%. Special lip-designed washers offer minor sealing to block dust and moisture.
Typical Applications:
- Insulated fastening in new energy vehicle battery packs (resisting electrolyte corrosion).
- Connections in outdoor solar 支架 (supports) to prevent electrochemical corrosion via UV-resistant black nylon.
- Metal-plastic component connections in medical devices (non-toxic, FDA-compliant, and smooth for safety).
Installation Guidelines and Maintenance Tips
- Installation: Clean burrs, rust, and oil from connection surfaces for tight 贴合 (adhesion). Place washers flat between bolts and substrates; avoid tool strikes on edges to prevent cracks or deformation.
- Tightening Torque: Adjust based on bolt size and washer thickness. For M6–M10 bolts with 1–2 mm washers, use 8–15 N·m to avoid plastic deformation from over-tightening.
- Maintenance: Inspect outdoor washers quarterly for cracks, hardening, or discoloration; replace aging units promptly.
- Storage: Keep unused washers in dry, ventilated areas away from direct sunlight, high temperatures, acids, alkalis, and organic solvents. Stack height ≤ 30 cm to prevent deformation. Clean oil-stained washers with neutral detergent and warm water; air-dry—avoid abrasive scrubbing.
Black nylon PA66 plastic flat washers provide irreplaceable protective solutions for modern fastening systems with their unique non-metallic properties. Advances in material modification—such as glass fiber reinforcement and molybdenum disulfide lubrication—continue to expand their applications. By mastering scientific selection and installation practices, these small components play a critical role in ensuring safe and stable equipment operation.