The WN1 Specification: A Critical Quality Requirement for Fasteners in the Defense and Industrial Sectors

What is the WN1 specification?

The WN1 series (WN1-1 through WN1-8) includes various coatings and quality levels for fasteners, developed as an alternative to standard specifications such as DIN EN ISO 4042and DIN EN ISO 10683. The goal is to use REACH-compliant, high-performance, and corrosion-resistant finishes that are suitable for, among other things:

• high mechanical stress;
• prolonged vibrations;
• temperature fluctuations;
• and exposure to harsh environments.

Why is WN1 important?

For applications where every connection counts—such as in the defense sector or in heavy-duty industrial systems—WN1 provides reliability in the following areas:

• mechanical reliability(strength classes such as 8.8 and higher);
• corrosion protection(e.g., ZnNi5 or ZnNi8 coatings);
• traceability and quality assurancethrough defined production and testing protocols;
• REACH compliance, which excludes harmful substances such as CrVI.

Technical Specifications

Depending on the application, different WN1 codes are used; for example:

• WN1-1:ZnNi5 coating with a coefficient of friction of µ0.12–0.18, suitable for fasteners up to M80.
• WN1-2:ZnNi8 coating for larger diameters (up to M300).
• WN1-4 & WN1-5:Zinc-coated fins, with high or standard corrosion resistance.
• WN1-6:Light Zn3 coating, especially for fine and small wire diameters.

Each specification is linked to a clearly coded designation (such as “ISO4762-M12x100-8.8-WN1-2”) that immediately indicates which standard and coating apply.

Practical Applications

Although originally developed for military applications, we are seeing the WN1 specifications used more and more frequently in other sectors where the safety, reliability, and service life of fasteners are crucial:

• Aviation and Aerospace
• Offshore and Shipbuilding
• Railway Infrastructure
• Power Plants and Nuclear Facilities
• Heavy Machinery Manufacturing

What does this mean for engineers and procurement professionals?

When selecting fasteners for critical applications, using parts that meet the WN1 specification provides a verifiable guarantee of quality. Suppliers who use WN1 designations thereby demonstrate that their parts meet the most stringent requirements for mechanical performance, corrosion protection, and traceability.

Want to learn more about fasteners that comply with WN1?

Please contact Archey for technical advice or access to our network of suppliers that work with WN1-classified fasteners.