Lock Washer

Lock Washer — Toothed & Serrated Lock Washer | DIN 6798 / DIN 6797 | High-Friction Anti-Loosening

Lock washers (toothed lock washers) provide superior anti-loosening performance through mechanical interlocking rather than spring tension alone. Manufactured to DIN 6798 (internal tooth) and DIN 6797 (external tooth) standards, our lock washers feature precision-stamped teeth that bite into both the fastener head/nut and the mating surface, creating a positive mechanical lock. Available in sizes from M4 to M24, lock washers are essential in electrical connections, thin sheet metal assemblies, and applications where maximum vibration resistance is required.

Material & Specifications

Size Range	M4 to M24 / #8 to 1″
Standard	DIN 6798 (Internal Tooth Type A), DIN 6797 (External Tooth Type J), JIS B 1255, GB/T 862.1, GB/T 862.2, ASME B18.21.1
Material	Carbon Steel (spring steel 65Mn, C75), 304 Stainless Steel (A2), 316 Stainless Steel (A4), Phosphor Bronze (electrical)
Surface / Coating	Hot-Dip Galvanized (HDG), Electroplated Zinc Blue/White, Color Zinc/Yellow, Dacromet, Multi-Element Alloy Co-Permeation, Nickel Plating (electrical)
Hardness	HRC 40-50 (carbon steel), HRC 30-40 (stainless steel)
Types	Internal Tooth (concealed, aesthetic), External Tooth (maximum grip, larger OD), Combined Internal/External, Countersunk External Tooth, Wave/Curved Type

Surface Treatment & Zinc Coating Quality

At BoltNutsPlus, we understand that surface treatment is critical to fastener longevity and performance. Our washers undergo rigorous coating processes to ensure maximum corrosion resistance and durability. We offer five premium coating options, each tested to international standards:

• Hot-Dip Galvanizing (HDG) — Thick zinc layer (50-120μm) providing superior long-term corrosion protection for outdoor, marine, and industrial environments. Compliant with ISO 1461 / ASTM A153 standards. Salt spray resistance: 500-1,000+ hours. HDG washers are ideal for structural steel assemblies exposed to harsh weather.
• Electroplated Zinc Blue-White (Zn Blue/White) — Bright, clean silver-blue appearance with 5-15μm zinc layer. Cr3+ passivation technology, fully RoHS compliant. Ideal for indoor machinery, electronics, and general-purpose applications requiring aesthetic appeal and moderate corrosion resistance.
• Color Zinc / Yellow Zinc (Iridescent Passivation) — Multi-colored iridescent passivation film offering enhanced corrosion resistance (100-200 hours salt spray) with a distinctive golden finish. Widely preferred in automotive, agricultural equipment, and construction machinery sectors for its balanced protection and visual appeal.
• Dacromet Coating — Advanced water-based zinc-chromium coating technology with NO hydrogen embrittlement risk. Provides 1,000+ hours salt spray resistance, making it the preferred choice for high-strength fasteners in extreme environments. Environmentally friendly (no heavy metal discharge), RoHS/ELV compliant, ideal for automotive and wind energy applications.
• Multi-Element Alloy Co-Permeation — Zinc-aluminum-rare earth alloy layer offering 2-3x the corrosion resistance of traditional galvanizing. Features self-healing properties at scratch points, ensuring long-term protection even in damaged areas. Ideal for critical infrastructure, power transmission towers, coastal projects, and marine installations.

Key Features

• Precision-stamped sharp teeth provide positive mechanical interlock by biting into both surfaces
• Internal tooth (DIN 6798 Type A) — concealed design preserves aesthetic appearance under the fastener head
• External tooth (DIN 6797 Type J) — larger outer diameter teeth provide maximum grip and torsion resistance
• Exceptionally effective on thin sheet metal, painted surfaces, and soft materials where split washers are ineffective
• Excellent electrical conductivity (with nickel or phosphor bronze variants) — ideal for grounding and bonding applications
• Low profile design suitable for confined spaces where traditional spring washers would protrude

Applications

• Electrical panels, switchgear, and busbar connections — grounding and anti-loosening in one
• Sheet metal assemblies, enclosures, and appliance manufacturing with thin substrates
• Automotive electrical systems, sensors, and electronic module grounding connections
• Telecommunications equipment racks, antenna mounts, and outdoor enclosure fastening
• Consumer electronics and appliance assembly requiring reliable, compact locking solutions
• Lighting fixtures, signage, and architectural metalwork installations

Why Choose BoltNutsPlus?

• ISO 9001:2015 Certified Manufacturing — consistent quality you can trust on every batch
• 15+ Years of Export Experience — serving 40+ countries across 6 continents
• Full Traceability — material certificates (EN 10204 3.1) and comprehensive test reports included
• Custom Packaging & OEM/ODM — your brand identity, your specifications, our precision manufacturing
• Third-Party SGS / Bureau Veritas Inspection Available upon request
• 24-Hour Quote Response — same-day reply for urgent requirements; standard 24-hour turnaround