Dual Lock Washers >465HV Grade 27MnCrB5 Hardened Steel GEOMET Surface Coating

Dual Lock Washers – >465HV Grade 27MnCrB5 Hardened Steel | GEOMET Surface Coating

FULLERKREG Dual Lock Washers in 27MnCrB5 hardened steel (>465HV) with GEOMET®-equivalent zinc-flake surface coating represent the high-performance standard for wedge-locking fasteners in heavy industrial, automotive, and structural applications. Engineered to DIN 25201 principles, each cam-faced washer pair delivers mechanical anti-loosening that intensifies under vibration and dynamic load — no adhesives, no deformation, no failure.

⚠️ Dimensional Compatibility Notice: Tolerances and mechanical specifications comparable to Nord-Lock®, Twin-Lock® and Heico-Lock® brand locking washers.

Material & Surface Treatment

Property	Details
Material Grade	27MnCrB5 Alloy Steel (Boron-Manganese-Chromium)
Hardness	>465 HV (through-hardened, quenched & tempered)
Surface Coating	GEOMET®-equivalent Zinc-Flake Coating (water-based, chromium-free)
Coating Thickness	Approx. 8–12 μm
Salt Spray Resistance	≥ 720 hours (ISO 9227)
Temperature Resistance	Up to +150°C continuous; peak up to +200°C
RoHS / ELV Compliance	Yes — chromium-free, cadmium-free, lead-free
Hydrogen Embrittlement	None — no electroplating process involved
Standard Reference	DIN 25201 / Wedge-Locking Washer Principle
Material Standard	EN 10083-3 (27MnCrB5)

Why 27MnCrB5 + GEOMET Coating?

The combination of boron-alloyed manganese-chromium steel and zinc-flake GEOMET coating is the industry benchmark for high-load, corrosion-resistant wedge-locking washers:

• ✅ >465 HV hardness — cam geometry maintains integrity under extreme clamping forces
• ✅ GEOMET coating — superior corrosion protection without hydrogen embrittlement risk
• ✅ Chromium-free & RoHS compliant — meets EU ELV and REACH regulations
• ✅ Consistent friction coefficient — predictable preload and torque behavior
• ✅ Reusable — coating survives multiple installation/removal cycles
• ✅ No special tools required — compatible with standard bolts and nuts

How Dual Lock Washers Work

Each FULLERKREG Dual Lock Washer set consists of two identical washers with radial teeth on the outer face and wedge-shaped cams on the inner face. Installed cam-face to cam-face, the cam angle exceeds the thread pitch angle — mechanically preventing rotational loosening under vibration, shock, or thermal cycling. The harder the external force tries to loosen the bolt, the tighter the washer pair grips.

• ✅ Cam angle > thread pitch angle → self-locking under vibration
• ✅ Radial teeth bite into mating surfaces for maximum grip
• ✅ Suitable for dynamic loads, thermal cycling, and shock environments
• ✅ Works with standard hex bolts, flange bolts, and nuts

Dimensional Specifications

Material: 27MnCrB5 Hardened Steel (>465HV)  |  Surface: GEOMET Zinc-Flake Coating  |  All dimensions in mm (per pair)

Thread Size	d1 min (mm)	d2 max (mm)	h ref (mm)	Approx. Pairs / kg
M5	5.3	11.0	3.2	~1300
M6	6.4	13.0	3.8	~750
M8	8.4	17.0	4.8	~300
M10	10.5	20.0	5.8	~160
M12	12.5	24.0	6.8	~85
M14	14.5	28.0	7.8	~55
M16	16.5	30.0	8.8	~38
M20	20.5	37.0	10.8	~20
M24	24.5	44.0	12.8	~11

d1 = inner bore diameter  |  d2 = outer diameter  |  h = total height per pair (reference value). Contact FULLERKREG for sizes outside this range or custom specifications.

Selection Guide

Application Scenario	Recommended Size	Key Consideration
Automotive & Heavy Vehicles	M8 – M20	High vibration, RoHS/ELV compliant GEOMET coating
Wind Turbine Structures	M16 – M24	Extreme dynamic load, long-term corrosion protection
Railway & Rolling Stock	M12 – M24	Shock & vibration resistance, EN standard compliance
Construction & Steel Structures	M12 – M24	High clamping force, outdoor corrosion resistance
Industrial Machinery & Pumps	M8 – M20	Cam-locking prevents loosening under dynamic load
Mining & Heavy Equipment	M16 – M24	>465HV hardness withstands extreme clamping forces
General Engineering	M5 – M16	Cost-effective anti-loosening for standard applications

Standard & Compliance

FULLERKREG Dual Lock Washers (27MnCrB5 / GEOMET) are manufactured in accordance with DIN 25201 design principles. The 27MnCrB5 steel meets EN 10083-3 alloy steel standards. GEOMET-equivalent zinc-flake coating complies with ISO 10683 (non-electrolytically applied zinc-flake coatings) and is free of hexavalent chromium, cadmium, and lead.

• 📋 Design Standard: DIN 25201 (Wedge-Locking Washers)
• 📋 Material Standard: EN 10083-3 (27MnCrB5 Alloy Steel)
• 📋 Coating Standard: ISO 10683 (Zinc-Flake, Non-Electrolytic)
• 📋 Corrosion Test: ≥ 720 h salt spray per ISO 9227
• 📋 RoHS / ELV / REACH: Compliant — Cr6+, Cd, Pb free
• 📋 Inspection: Dimensional & visual per batch; hardness spot-check
• 📋 Packaging: Bulk bag / box, labeled with size, grade, coating, and lot number
• 📋 Mill certificates & coating test reports available on request

Product Gallery

FULLERKREG Dual Lock Washers 27MnCrB5 GEOMET – actual product photos

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Why Choose FULLERKREG?

🏭 Direct Manufacturer	Factory-direct pricing with full production traceability and batch records
🔬 Material Certified	27MnCrB5 with EN 10083-3 mill certificates and hardness test reports on request
🛡️ GEOMET Coating	Zinc-flake coating ≥720h salt spray, RoHS/ELV compliant, no hydrogen embrittlement
📦 Flexible MOQ	Small sample orders to full container loads — wholesale pricing available
🌍 Global Shipping	Worldwide export with DDP / DAP / FOB terms available
⚙️ Custom Specifications	Non-standard sizes, alternative coatings, and OEM packaging available on request
💬 Technical Support	Engineering team available for product selection and application guidance

📩 Request a quote or technical datasheet: Contact the FULLERKREG sales team for bulk pricing, custom specifications, and lead time confirmation.