In construction, metalworking, and industrial manufacturing, the choice of fasteners directly affects efficiency, safety, and durability. Bi metal self drilling screws, with their unique composite structure and outstanding performance, have become an ideal solution for global engineering projects. This article provides a full overview—from definition and features to applications, installation, and purchasing standards—to help you make informed decisions.
1. Challenges of Standard Screws vs. Bi-Metal Advantages
Common issues with carbon steel screws:
- Prone to rust → require coatings or frequent replacement.
- Difficult to penetrate thick steel plates → high torque demand, frequent seizing, or drill point wear.
- Limited durability → higher long-term maintenance costs.
Bi-metal self drilling screw solutions:
- High-strength drill point: Hardened alloy or carbon steel drill tips easily penetrate 0.5–6mm steel plates.
- Stainless steel shank: SUS304 or SUS316, with salt spray resistance of 1,000–5,000 hours.
- One-step fastening: Combines drilling and fastening in a single process, improving efficiency by 30%–50% and reducing labor costs.
For example, Ningbo Sunlong manufactures bi metal self drilling screws using advanced composite processes that combine drilling strength with corrosion resistance. Their products have been used in coastal solar mounting projects for years without rusting or loosening.
2. Key Performance Parameters
| Parameter | Description | Buyer’s Focus |
|---|---|---|
| Diameter | 3.5–10mm | Match to material thickness |
| Length | 12–200mm | Ensure thread engagement ≥ 3 pitches |
| Drilling Capacity | 0.5–6mm steel plate | Match substrate thickness |
| Tensile Strength | 650–1050MPa | Ensure structural reliability |
| Shank Material | SUS304 / SUS316 | Salt spray ≥ 1000h |
| Surface Treatment | Zinc plating, Ruspert coating | Improved corrosion resistance |
| Head Types | Hex, countersunk, pan | Match different tool requirements |
It is recommended to obtain full datasheets and test reports from qualified suppliers such as Ningbo Sunlong to compare models and brands.
3. Applications
- Steel roofing and wall systems: Ensure secure fastening and prevent leakage.
- Solar power stations: Withstand outdoor heat, wind, rain, and salt spray.
- Cold storage and chemical facilities: Resist low temperatures, high humidity, and corrosive media.
- Metal curtain walls and bridge projects: Balance aesthetics with structural safety.
Bi metal self drilling screws are widely applied in solar racking and metal construction projects. Their corrosion resistance and drilling performance make them highly trusted by global contractors and distributors.
4. Technical Selection Guide
When selecting bi metal self drilling screws, focus on:
- Diameter & Length: Common diameters are 4.8mm and 6.3mm, with lengths suited to substrate thickness.
- Drilling Capacity: Choose drill point design according to steel thickness.
- Head Types: Hex, pan, or countersunk heads for different installation requirements.
- Material Standards: Carbon steel drill point + SUS304/316 shank, compliant with DIN, ISO, ASTM.
Professional suppliers such as Ningbo Sunlong provide full specifications and test reports to make selection easier for engineers.
5. Proper Installation Practices
- Tools: Variable-speed drill (800–1500 RPM) with magnetic driver bit.
- Positioning: Drill vertically; start at low speed, then increase gradually.
- Torque Control: Slow down when the screw head nears the surface to prevent over-tightening or breakage.
- Final Check: Ensure the screw head sits flush with the surface and threads fully penetrate.
Proper installation ensures reliable fastening and extends the service life of both screws and structures. Ningbo Sunlong also provides instructional videos and installation guides on their official website.
6. Purchasing and Wholesale Recommendations
When sourcing bi metal self drilling screws in bulk, buyers should carefully review:
- Factory Certification: ISO9001 (quality management system)
- Product Standards: ASTM, DIN
- Salt Spray Test Reports: ≥ 1000h recommended
- Supply Capacity & Lead Time
- OEM / Customization Support
As a professional manufacturer, Ningbo Sunlong not only offers bulk purchasing but also supports custom specifications and OEM services, making them a reliable partner for large construction projects and distributors.
By combining strong drilling capability with long-lasting corrosion resistance, bi metal self drilling screws have become a preferred fastening solution in construction, solar, and metal engineering projects.
Contact Ningbo Sunlong today for wholesale quotes, free samples, and detailed specifications to support your next project.
