Lock Nut

Lock Nut — Anti-Vibration Prevailing Torque Nut | DIN 985 / DIN 980 | Nylon Insert & All-Metal

Lock nuts are engineered to resist loosening under vibration, shock, and dynamic loads — the leading cause of fastener failure in mechanical systems. Manufactured to DIN 985 (nylon insert), DIN 980 (all-metal), and ISO 2320 standards, our lock nuts are available in M3 to M36 sizes in carbon steel and stainless steel. The nylon insert type uses a resilient nylon collar that creates frictional resistance on the bolt thread, while the all-metal type uses a deformed top thread section for high-temperature applications. Both designs provide reliable prevailing torque for automotive, machinery, railway, and aerospace fastening.

Material & Specifications

Size Range	M3 to M36 / 1/8″ to 1-1/2″
Standard	DIN 985 (nylon insert), DIN 980 (all-metal), DIN 6925 (flanged lock), ISO 2320, IFI 100/107
Material	Carbon Steel (Grade 5, 8, 10), 304 Stainless Steel (A2), 316 Stainless Steel (A4)
Surface / Coating	Electroplated Zinc (Blue/White, Yellow/Color), Dacromet, Multi-Element Alloy Co-Permeation, Hot-Dip Galvanized, Plain/Black Oxide
Lock Type	Nylon Insert (DIN 985) or All-Metal Prevailing Torque (DIN 980)
Temperature Range	-40°C to +120°C (nylon insert), -40°C to +300°C (all-metal)

Surface Treatment & Zinc Coating Quality

Lock nuts used in automotive, railway, and industrial applications require superior corrosion resistance to maintain prevailing torque performance over time. We offer five premium coating options:

• Hot-Dip Galvanizing (HDG) — Thick zinc layer (50-120μm) providing superior corrosion protection for outdoor and structural lock nut applications. Compliant with ISO 1461 / ASTM A153. Note: HDG may affect nylon insert performance; all-metal lock nuts (DIN 980) recommended for HDG.
• Electroplated Zinc Blue-White (Zn Blue/White) — Bright silver-blue finish with 5-12μm zinc layer. Cr3+ passivation, RoHS compliant. The most common finish for DIN 985 nylon insert lock nuts — does not affect nylon collar performance. Baked post-plating to prevent hydrogen embrittlement.
• Color Zinc / Yellow Zinc (Iridescent Passivation) — Golden-iridescent multi-colored passivation providing 150-250 hours salt spray resistance. Preferred for automotive and machinery lock nuts requiring enhanced corrosion protection with visual identification.
• Dacromet Coating — Water-based zinc-chromium coating with NO hydrogen embrittlement risk. 1,000+ hours salt spray resistance. The ideal coating for high-strength all-metal lock nuts (Grade 10/12) in automotive, railway, and heavy machinery applications. Does not affect thread tolerance or prevailing torque.
• Multi-Element Alloy Co-Permeation — Zinc-aluminum-rare earth alloy layer offering 2,000+ hours salt spray resistance. Self-healing at scratches. Used in critical infrastructure lock nuts for power transmission, wind energy, and coastal installations.

Key Features

• Prevailing torque design prevents loosening under vibration and dynamic loads
• Nylon insert type is reusable up to 5-10 reassembly cycles
• All-metal type rated for high-temperature service up to 300°C
• Available with flanged base (DIN 6925) for applications requiring integrated washer
• Tested to ISO 2320 prevailing torque specifications — guaranteed clamping retention

Applications

• Automotive engine, suspension, and brake system fastening
• Industrial machinery and equipment subject to vibration
• Railway track and rolling stock connections
• Wind turbine and power generation equipment
• Construction equipment and mining machinery

Why Choose BoltNutsPlus?

• ISO 9001:2015 Certified Manufacturing — consistent quality you can trust
• 15+ Years of Export Experience — serving 40+ countries worldwide
• Full Traceability — material certificates (EN 10204 3.1) and test reports included
• Custom Packaging & OEM/ODM — your brand, your specifications
• Third-Party SGS / Bureau Veritas Inspection Available
• 24-Hour Quote Response — same-day reply for urgent requirements