Home » Hexagon Nylon Locking Nuts (DIN 985) - Marine Stainless Steel (A4)

Hexagon Nylon Locking Nuts (DIN 985) - Marine Stainless Steel (A4)

DIN 985 Hexagon Nylon Insert Lock Nuts – Marine Stainless Steel A4 (SUS316)

FULLERKREG DIN 985 nylon insert lock nuts in marine-grade stainless steel A4 (SUS316 / 1.4401) offer superior corrosion resistance compared to standard A2 grades, making them the preferred choice for saltwater, chloride-rich, and aggressive chemical environments. The integrated nylon collar provides reliable prevailing torque, resisting loosening under vibration and dynamic loads without damaging the mating thread. Manufactured to DIN 985 / ISO 7042 with full A4-70 mechanical compliance.

Product Specifications

Attribute Details
Standard DIN 985 / ISO 7042
Type Hexagon Nylon Insert Lock Nut (Prevailing Torque)
Material Marine Stainless Steel A4 / SUS316 / 1.4401
Strength Grade A4-70
Surface Finish Passivated & Bright (洗白 钝化)
Thread Metric Coarse Thread (ISO 68-1)
Size Range M3 – M20
Insert Material Nylon (Polyamide PA66)
Temperature Range -73°C to +120°C
Mo Content (SUS316) 2.0 – 2.5% Molybdenum (enhanced pitting resistance)
RoHS Compliant Yes
Brand FULLERKREG

Dimensional Data (DIN 985 – Class 8, Metric)

All dimensions in millimeters (mm). Unit weight (单重) is approximate reference value.

Nominal Size Pitch (mm) F – Width Across Flats Max (mm) F – Width Across Flats Min (mm) G – Width Across Corners Min (mm) H – Thickness Max (mm) H – Thickness Min (mm) I – Wrenching Height Min (mm) 单重 (g/pc)
M3 0.5 5.50 5.32 6.01 4.0 3.7 2.4 ~0.5
M4 0.7 7.00 6.78 7.66 5.0 4.7 2.9 ~1.0
M5 0.8 8.00 7.78 8.79 5.0 4.7 3.2 ~1.6
M6 1.0 10.00 9.78 11.05 6.0 5.7 4.0 ~3.0
M7 1.0 11.00 10.73 12.12 7.5 7.14 4.7 ~4.5
M8 1.25 13.00 12.73 14.38 8.0 7.64 5.6 ~6.5
M10 1.5 17.00 16.73 18.90 10.0 9.64 6.5 ~12
M12 1.75 19.00 18.67 21.10 12.0 11.57 8.0 ~20
M14 2.0 22.00 21.67 24.49 14.0 13.3 9.5 ~32
M16 2.0 24.00 23.67 26.75 16.0 15.3 10.5 ~48
M18 2.5 27.00 26.16 29.56 18.0 17.66 13.0 ~68
M20 2.5 30.00 29.16 32.95 20.0 19.7 14.0 ~95

* Dimensions per DIN 985 / ISO 7042. Unit weight values are approximate and for reference only. Actual weight may vary slightly by batch.

A4 vs A2 – Why Choose Marine Grade?

Property A2 (SUS304) A4 (SUS316) ✓ This Product
Molybdenum Content None 2.0 – 2.5%
Salt Spray Resistance Good Excellent
Chloride Pitting Resistance Moderate Superior
Chemical Resistance Good Excellent (acids, chlorides)
Recommended Environment General outdoor / indoor Marine, coastal, chemical, food
Strength Grade A2-70 A4-70

Selection Guide

Application Scenario Recommended Size Key Consideration
Marine & offshore structures M6 – M20 A4 resists saltwater & chloride pitting
Coastal & outdoor infrastructure M8 – M20 Long-term corrosion protection in humid air
Chemical processing equipment M6 – M16 Mo content resists acid & chloride attack
Food & pharmaceutical machinery M5 – M16 SUS316 meets hygienic & washdown standards
Swimming pools & water treatment M6 – M16 Chlorinated water resistance critical
Vibration-prone assemblies M8 – M20 Nylon insert locks against loosening

Standard & Compliance

These nylon insert lock nuts are manufactured in full compliance with DIN 985 and the equivalent international standard ISO 7042. Mechanical properties meet A4-70 grade requirements as defined in ISO 3506-2. Material composition conforms to ASTM A276 / EN 10088 for 1.4401 (SUS316) marine stainless steel. All products are RoHS compliant.

  • Proof Load (N/mm²): 800
  • Hardness: Vickers HV 5: 302 max / Rockwell C: 30 max
  • Applicable bolt class: Class 8.8 or less (M3–M16); Class 10.9 or less (M18–M20)
  • Plating: Standard passivated bright finish; zinc-plated versions available on request

Product Gallery

DIN 985 A4 Marine Stainless Steel Nylon Insert Lock Nuts – actual product photos:

       

Why Choose FULLERKREG?

  • 🏭 Direct Manufacturer – Factory-direct pricing with no middlemen, ensuring competitive wholesale rates
  • ✅ Strict Quality Control – 100% dimensional inspection; material certificates (MTC) available on request
  • 📦 Flexible MOQ & Packaging – Custom packaging quantities, OEM labeling, and bulk bag or box options
  • 🚢 Global Shipping – FBA-ready shipments to Amazon warehouses; direct export to 50+ countries
  • 🔬 Engineering Support – Technical datasheets, CAD drawings, and application guidance available
  • ⚡ Fast Lead Times – In-stock items ship within 3–5 business days; custom orders within 15–25 days

Frequently Asked Questions

Q: What makes A4 (SUS316) better than A2 (SUS304) for marine use?
A: A4 contains 2.0–2.5% molybdenum, which significantly improves resistance to chloride-induced pitting and crevice corrosion — the primary failure mode in saltwater and coastal environments. A2 lacks this element and is not recommended for prolonged marine exposure.

Q: Can DIN 985 A4 nylon lock nuts be reused?
A: They can be reused a limited number of times. For critical safety applications, single-use is recommended as the nylon insert loses prevailing torque effectiveness after repeated cycling.

Q: What is the difference between DIN 985 and DIN 982?
A: DIN 985 is a thin (low-profile) nylon insert lock nut; DIN 982 is the full-height version. DIN 985 suits space-constrained assemblies; DIN 982 provides higher prevailing torque retention.

Q: Are these suitable for high-temperature environments?
A: The nylon insert is rated for -73°C to +120°C. For applications above 120°C, consider all-metal prevailing torque nuts (e.g., DIN 980 in A4).

Q: Do you provide material test certificates?
A: Yes. Mill test certificates (MTC), RoHS declarations, and EN 10204 3.1 certificates are available upon request for all orders.

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