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China Cross Flange Self Tapping Screw Suppliers - Quality Factory Direct Pricing and Fast Delivery
| FOB Price | US $0.5 – 9,999 / Piece |
| Min. Order Quantity | 100 Piece/Pieces |
| Supply Ability | 10,000 Piece/Pieces per Month |
Materials and Surface Treatment
Common Materials
- Carbon Steel: Low cost, high strength; surface requires rust prevention treatment, such as galvanizing and Dacromet.
- Stainless Steel (304/316): Strong corrosion resistance, suitable for humid or chemical environments.
- Aluminum Alloy / Copper: Lightweight or conductive demand scenarios, but with lower strength.
Surface Treatment
- Galvanization: Divided into electroplating (blue and white zinc, color zinc) and hot-dip galvanizing; generally rust resistant, suitable for indoor environments.
- Dacromet (Zinc Chromium Coating): No risk of hydrogen embrittlement, high temperature resistance, corrosion resistance; used in automobiles and outdoors.
- Phosphating: Increases lubricity and reduces installation friction.
- Nylon Coating: Insulation, anti-loosening; commonly used in electronic devices.
Application Fields
- Automotive Manufacturing: Sheet metal parts, interior panels, and wiring harness fixation — must be shock resistant and anti-loose.
- Electronic Appliances: Circuit board and shell assembly; mainly small size (M2–M4) to avoid conductive interference.
- Architectural Decoration: Installation of color steel plates, aluminum alloy doors and windows, and protection of flange surfaces from scratches.
- Mechanical Equipment: Panels and enclosures fixed to withstand vibration environments.
Specifications and Standards
Common Specifications
- Nominal Diameter: M2 to M12 (commonly M4–M6).
- Length Range: 6mm to 100mm, depending on application requirements.
- Flange Diameter: Usually 2–3 times the diameter of the screw (e.g., M5 flange surface diameter of approx. 10–15mm).
International Standards
- National Standard: GB/T 15856.4 (Pan head cross flange self-tapping screws).
- German Standard: DIN 7500 (Technical standard for self-tapping screws).
- American Standards: ANSI/ASME B18.6.4, SAE J78 (automotive applications).
Frequently Asked Questions
What is the difference between electroplated galvanizing and hot-dip galvanizing on flange screws?
Electroplated galvanizing (blue/white zinc or color zinc) produces a thinner, more uniform coating suitable for indoor and light-duty applications. Hot-dip galvanizing creates a thicker zinc layer, offering superior corrosion protection for outdoor and heavy-duty environments.
Which material is best for flange screws used in humid or chemical environments?
Stainless steel grades 304 or 316 are recommended for humid or chemically aggressive environments due to their strong corrosion resistance. Grade 316 offers even better resistance to chlorides and is ideal for marine or industrial chemical settings.
What size flange screws are most commonly used in automotive manufacturing?
In automotive manufacturing, flange screws in the M4–M8 range are most commonly used. They must meet standards such as SAE J78 or ANSI/ASME B18.6.4 and are typically treated with Dacromet coating for vibration resistance and corrosion protection.
What is Dacromet coating and why is it preferred for outdoor applications?
Dacromet (zinc chromium coating) is a water-based surface treatment that provides excellent corrosion resistance without the risk of hydrogen embrittlement. It also withstands high temperatures, making it ideal for automotive components and outdoor structural applications.
What international standards apply to flange self-tapping screws?
Flange self-tapping screws are governed by several international standards: GB/T 15856.4 (Chinese national standard), DIN 7500 (German standard), and ANSI/ASME B18.6.4 / SAE J78 (American standards, especially for automotive use). Always verify the applicable standard for your specific application.
What is the minimum order quantity and what is the typical lead time?
The minimum order quantity is 100 pieces per order. With a supply ability of 10,000 pieces per month, lead times are generally short for standard specifications. Custom sizes or special surface treatments may require additional production time — please contact us for a specific quote.