Product Summary

Longze Wedge-Locking Anti-Vibration Washers (DIN 25201) are the ultimate solution for securing bolted joints subjected to extreme vibration and dynamic loads. Manufactured

in Yongnian, China, our self-locking system consists of a pre-assembled pair of washers with cams on the inside and radial teeth on the outside. By utilizing the "wedge-effect," the

rise of the internal cams is greater than the bolt thread pitch, ensuring that any attempt by the bolt to loosen actually increases the clamping tension. Whether for high-speed rail

tracks, crushing equipment, or offshore wind turbines, Longze wedge-lock washers provide a fail-safe mechanical lock that outperforms standard spring or nylon-insert fasteners.

• ✔ Geometric Self-Locking: The cam angle ($\alpha$) is designed to be larger than the thread pitch angle ($\beta$). This mechanical advantage ensures the bolt remains pre-loaded even under the most severe Junker vibration tests.

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• ✔ High-Hardness "Bite": Our carbon steel washers are through-hardened to $\ge$ 465 HV, ensuring they are harder than Grade 12.9 bolts, allowing the radial teeth to grip the mating surfaces effectively.

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• ✔ Pre-Glued Convenience: To prevent onsite installation errors, Longze washers are supplied in pre-glued pairs (cam-to-cam), ensuring they are always installed in the correct orientation for maximum safety.

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• Standards: DIN 25201-4, NL Series (Standard & Large OD).

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• Size Range: M3 to M130 | #5 to 5" (Imperial).

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• Material Grade: Alloy Steel (Chrome-Vanadium) | Stainless Steel 316 (A4).

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• Surface Hardness: $\ge$ 465 HV1 (Steel) | $\ge$ 520 HV0.05 (Surface Hardened SS316).

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• Surface Finish: Delta Protekt / Zinc Flake Coating (Chrome-free), Plain.

Mechanical Properties & Material Standards

• Matching the hardness and tension requirements for extreme industrial vibration.

• Material Type	Core Hardness	Surface Hardness	Tensile Support	Resistenza alla corrosione
  Alloy Steel	420 - 480 HV	$\ge$ 465 HV	Grade 12.9 Bolts	High (with Coating)
  SS316 (A4)	200 - 300 HV	$\ge$ 520 HV	Grade 8.8 / A4-80	Extreme (Marine)
  254 SMO	240 - 320 HV	$\ge$ 550 HV	Special Alloy	High Acid / Salt

Standard Cross Arm Dimensions

• Common dimensions for standard (NL) and large OD (NLSP) wedge washers.

• Thread Size (D)	Inner Dia (di)	Outer Dia (do)	Thickness (T)	Min. Bolt Grade
  M10 / 3/8"	10.7 mm	16.6 mm	2.5 mm	Grade 8.8 / 10.9
  M12 / 1/2"	13.0 mm	19.5 mm	2.5 mm	Grade 8.8 / 10.9
  M16 / 5/8"	17.0 mm	25.4 mm	3.4 mm	Grade 10.9 / 12.9
  M20 / 3/4"	21.4 mm	30.7 mm	3.4 mm	Grade 10.9 / 12.9

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Surface Treatment	Process	Salt Spray Test	Best Application	Friction Consistency
  Zinc Flake	Delta Protekt	600 - 1000 Hours	Infrastructure / Rail	Excellent
  Plain (Steel)	Heat Treated	< 12 Hours	Internal Gearboxes	High
  SS316 Hardened	Diffusion	1000+ Hours	Offshore / Chemical	Excellent

Avoid Pitfalls:

• Soft Surface Issues: If the mating surface is significantly harder than the washer (e.g., hardened tool steel), the radial teeth cannot "bite," and the locking effect is reduced. We recommend checking surface hardness before installation.

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• Lubrication Management: Wedge-lock washers work perfectly with lubricants, but the lubrication reduces friction. Longze provides specialized Torque-to-Tension charts to ensure you don't overstretch the bolt while achieving the self-locking effect.

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• Reuse Guidelines: While reusable, the "teeth" and "cams" wear down over time. We recommend a visual inspection; if the radial teeth are flattened, replace the pair to ensure 100% vibration resistance.

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Perfect Fit Assembly:

• Large OD (SP Series): For use on oversized holes, slotted holes, or painted/soft surfaces, always choose our Large OD Wedge Washers to distribute the clamping force more evenly.

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• Tapped Holes: When installing into a tapped hole (rather than a nut), only one pair of washers is needed under the bolt head to lock the entire assembly.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including Junker Vibration Testing, Micro-hardness profile analysis, and 100% cam-angle verification.

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• Sea-Worthy Packaging: Pairs are packed in sealed inner boxes (e.g., 50 or 100 pairs) to maintain the pre-glued bond, then secured in reinforced master cartons for maritime export from our Yongnian hub.

• Q: Can I use these with locking nuts? A: No. Wedge-lock washers work by tension, while locking nuts work by friction. Using both can interfere with the wedge-locking principle.

• Q: Why are they pre-glued? A: To ensure the "cams" are facing each other. If installed with the radial teeth facing each other, the washer will fail to lock.