Engineered for Extreme Environments | Reliable Performance for Demanding Applications
At Sunlong Screw, we specialize in high-performance fastening solutions. Our Super Anti-Corrosion Bi-Metal Self-Drilling Screws are designed to deliver exceptional strength and corrosion resistance in the most demanding industrial and marine environments.
Product Overview
This advanced bi-metal screw features a two-part construction joined by precision welding to ensure structural integrity and long-term performance:
- Component A – Stainless Steel Head and Shank:
Constructed from high-grade 300 series stainless steel, this section remains exposed to air and bears full mechanical stress after fastening. The surface is treated with Ruspert® coating, which enhances corrosion resistance and prevents galvanic reactions with dissimilar materials. - Component B – Hardened Drilling Point:
Made from carbon steel, the self-drilling tip ensures fast, clean penetration into steel, aluminum, and other hard substrates — no pre-drilling is required.
Key Features
✅ Superior Corrosion Resistance:
Complies with AS 3566.2-2002 standards and performs reliably in ISO Class 3, 4, and even Class 5 corrosion environments.
✅ Durable Bi-Metal Weld Joint:
Ensures a solid bond between dissimilar metals, providing excellent mechanical and environmental stability.
✅ Enhanced Surface Protection:
The Ruspert® coating on stainless steel components minimizes surface wear and galvanic corrosion, even in salt-laden air or industrial zones.
✅ Versatile Drill Point Options:
Available in hardened carbon steel or alloy steel tips, suitable for a wide range of building and fabrication applications.
✅ Leak-Proof EPDM Bonded Washer:
Each screw includes a high-performance EPDM washer, creating a secure, weather-resistant seal.
✅ RoHS Compliant:
Free of hexavalent chromium (Cr6+), lead (Pb), and other restricted substances. Fully compliant with EU RoHS directives for health and environmental safety.
Corrosion Resistance Classification
| Classification | Requrements of Corrosion Resistance |
| Class1 | Generaluse in indoor application.AS2331.3.1 SST:72H |
| Class2 | General use in outdoor aplications with low levels of pollution.AS2331.3.1 SST:240H.DIN50018 Kesternich test5 Cycles |
| Class 3 | Outdoor use in mild industrial or marine environment.AS2331.3.1 SST:1000H.DIN50018 Kesternich test:15 Cycles |
| Class 4 | Outdoor use in severe marine environmentAS2331.3.1 SST:1500H.DIN50018 Kesternich test:25 Cycles |
| Class 5 | utbor usein highy severe marine environment.The use of SUS 304/316 Bl-metal screws are highly recommended |
Why Choose Sunlong Bi-Metal Screws?
With over a decade of experience in advanced fastening technology, Sunlong Screw delivers high-reliability solutions backed by international certifications and robust quality control. Our bi-metal screws are tested to withstand extreme corrosion, ensuring long-lasting performance in mission-critical applications.
Need a Custom Solution?
Our engineering team can assist with customization, technical consultation, and testing reports to meet your unique project needs.
📧 Email: sales@nbsunlong.com
🌐 Website: www.nbsunlong.com
