Ruspert & Dacromet Coatings: The Gold Standard in Fastener Corrosion Protection

2026-04-22

When it comes to long-term structural integrity in demanding environments, the coating on your screws, bolts, and fasteners matters as much as the steel itself. Ruspert and Dacromet coatings represent two of the most advanced surface-treatment technologies available — and at FUJINRUI, they define everything we make.

1,000+

Hours Salt Spray (Ruspert)

720+

Hours Salt Spray (Dacromet)

Zero

Hydrogen Embrittlement Risk

What Is Dacromet Coating?

Dacromet (also spelled Dacrotized or Zinc-Chrome) is a water-based, chromate-zinc flake coating system originally developed by Diamond Shamrock Corporation and widely adopted across the automotive, construction, and marine industries. Applied by dipping and baking at approximately 300 °C, it forms a tightly bonded, multi-layer metallic film over the substrate.

When used on hex bolts, flange bolts, self-tapping screws, and socket-head cap screws, Dacromet delivers a consistent silver-gray finish with exceptional corrosion resistance — typically exceeding 720 hours in neutral salt spray testing (NSS, ISO 9227).

Key Advantages of Dacromet

Exceptional salt-spray resistance— 720+ hours with no red rust on steel fasteners
No hydrogen embrittlement— safe for high-tensile-grade bolts (Grade 8.8, 10.9, 12.9)
Excellent adhesion— mechanical bond integrates with base metal without peeling or blistering
Heat resistance— retains protective properties up to 300 °C
Thin film profile— coating thickness of only 4–8 µm, ideal for threaded fasteners with tight tolerances
Environmentally friendly— low-VOC, water-based formulation vs. traditional cadmium plating

Common applications include automotive chassis bolts, solar panel mounting screws, steel structure anchor bolts, and heavy-duty hex flange bolts used in outdoor infrastructure where long-term exposure to moisture, salt, and industrial chemicals is expected.

What Is Ruspert Coating?

Ruspert is a proprietary three-layer composite coating system developed in Japan and widely regarded as a premium upgrade to Dacromet. The system applies three distinct layers — a zinc-aluminum flake base coat, an inorganic intermediate sealer, and an organic topcoat — creating a formidable multi-barrier defense against corrosion.

For dry-wall screws, self-drilling screws, drywall fasteners, and structural bolts deployed in coastal, humid, or chemically aggressive environments, Ruspert is often the definitive choice. FUJINRUI's Ruspert-coated dry-wall screws achieve over 1,000 hours in neutral salt spray testing — a benchmark that few competitive coatings can match.

Key Advantages of Ruspert

1,000+ hour salt spray performance— market-leading corrosion protection for screws and bolts
Three-layer composite system— zinc-aluminum base + inorganic sealer + organic topcoat
Superior adhesion and flexibility— withstands mechanical stress during installation without cracking
Excellent chemical resistance— resistant to acids, alkalis, and industrial solvents
RoHS compliant— free from hexavalent chromium (Cr6+), meeting the most stringent EU environmental standards
Consistent appearance— uniform dark silver-gray finish with a professional industrial aesthetic

Ruspert vs. Dacromet: Side-by-Side Comparison

Feature	Dacromet	Ruspert
Salt Spray Resistance	720+ hours	1,000+ hours ★ Superior
Coating Layers	Single-layer zinc-chromate	Three-layer composite system
Hydrogen Embrittlement	None	None
Cr6+ (Hexavalent Chromium)	May contain trace amounts	Cr6+ Free (RoHS)
Film Thickness	4-8 um	8-14 um
Chemical Resistance	Good	Excellent (Multi-barrier)
Typical Applications	Automotive, solar, steel structure bolts & screws	Marine, coastal, drywall screws, structural fasteners
Cost Tier	Standard premium	High-performance premium

Which Fasteners Benefit Most?

Both coating systems are applicable across a wide range of standard and specialty fasteners. At FUJINRUI, we apply Dacromet and Ruspert to:

Hex head bolts(M6–M36) for structural steel and heavy equipment
Flange boltsfor high-vibration assemblies requiring secure clamping
Socket-head cap screws (Allen bolts)for precision machinery
Self-tapping screwsfor light gauge steel and metal roofing
Self-drilling screwsfor faster installation without pre-drilling
Drywall screws— our flagship Ruspert-coated product, 1,000-hour NSS certified
Machine screwsfor electronics and industrial enclosures in humid conditions

Whether you need a reliable, cost-effective Dacromet solution for a large-scale infrastructure project, or the highest-tier Ruspert protection for harsh offshore or coastal environments, FUJINRUI has a tailored fastener solution ready to specify.

Why Choose FUJINRUI?

Founded in Hebei Province — the heartland of China's fastener manufacturing industry — FUJINRUI specializes exclusively in anti-corrosion fastener solutions. Unlike general-purpose hardware suppliers, we focus our entire operation on delivering coated bolts, screws, and specialty fasteners that perform reliably in the world's most demanding environments.

Our in-house Dacromet coating capability and exclusive Ruspert coating allow us to maintain strict quality control from raw material sourcing through final salt-spray certification — so that every hex bolt, machine screw, and drywall fastener that leaves our facility meets the specification you ordered.

Ready to Upgrade Your Corrosion Protection?

Whether you're sourcing Ruspert-coated drywall screws, Dacromet hex bolts, or need a custom anti-corrosion solution for your project — our team is here to help. Get a free technical consultation and competitive quote within 24 hours.

Response guaranteed within 24 hours | Free samples available | OEM & bulk orders welcome

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