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Yellow Zinc Plated Hex Flange Bolt DIN6921 - High-Quality Chinese Suppliers and Factory Direct Prices
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Yellow Zinc Plated Hex Flange Bolt DIN6921 - High-Quality Chinese Suppliers and Factory Direct Prices

Discover high-quality fasteners from our China factory, offering competitive FOB prices ranging from US $0.6 to $9.99 per piece. With a minimum order quantity of just 100 pieces and a robust supply ability of 10,000 pieces per month, we cater to various industrial needs. Our products undergo multiple surface treatments, including plain, zinc plated (ZP), galvanized, hot dip galvanized, and Dacromet, ensuring durability and performance. Made from premium materials such as carbon steel, alloy steel, stainless steel, brass, and copper, our fasteners meet international standards such as DIN, GB, UNC, BSW, and JIS. All products are certified with ISO9001, ISO14001, ISO45001, and SGS, guaranteeing quality and reliability. Choose from various grades including 4.8, 8.8, 10.9, 12.9, A2-70, A4-70, and A4-80. Partner with leading suppliers in China for your fastener solutions today!

    Flange bolt, also known as flange bolt, is a special type of bolt with a flange surface (flange), widely used in situations that require high preload, anti-loosening, and sealing. Here is a detailed introduction:

    Structural Characteristics
    Flange Surface Design

    There is an integral flange (circular gasket) below the bolt head, which increases the contact area, disperses pressure, and reduces damage to the connection surface.

    Hexagonal or Twelve-Pointed Head

    Commonly designed as a hexagonal head, easy to tighten with standard tools; some high-strength models use twelve corner heads.

    Anti-Slip Tooth Pattern

    The flange surface of some flange bolts has radial tooth patterns to enhance friction and prevent loosening.

    Main Advantages
    No Need for Additional Gaskets

    The integrated flange replaces traditional gaskets, simplifies installation steps, and reduces costs.

    Anti-Vibration and Anti-Loosening

    The flange surface increases friction, and the tooth pattern design further prevents bolts from loosening in vibration environments.

    Uniform Force Distribution

    The flange disperses the load, protects the surface of the connected parts, and avoids crushing or deformation.

    Sealing Enhancement

    When combined with flange surfaces and soft materials such as rubber gaskets, the sealing performance can be improved.

    Common Application Areas
    🚗 Automotive Industry

    Key parts such as the engine, gearbox, and wheel hub are adapted to high vibration environments.

    ⚙️ Machinery Manufacturing

    Heavy equipment, machine tools, pumps, valves, and other connections that require high preload force.

    🏗️ Architecture & Steel Structures

    Wind and earthquake resistant structures such as bridges, steel frames, curtain walls, etc.

    🚆 Rail Transit

    Scenarios with high requirements for safety and reliability, such as rail vehicles and signal equipment.

    Material & Surface Treatment
    🔩 Common Materials
    • Carbon steel (e.g., Grade 4.8, 8.8, 10.9)
    • Stainless steel (A2-304, A4-316, corrosion-resistant)
    • Alloy steel (high-strength or high-temperature resistant)
    🛡️ Surface Treatment
    • Galvanized (conventional anti-corrosion)
    • Dacromet (high corrosion resistance)
    • Hot dip galvanizing (heavy-duty anti-corrosion, suitable for outdoor use)
    • Phosphating (enhancing wear resistance)
    Frequently Asked Questions
    Q What is the main difference between a flange bolt and a standard hex bolt?
    A flange bolt features an integrated flange (wide washer-like base) beneath the head, which distributes clamping load over a larger surface area. A standard hex bolt requires a separate washer to achieve a similar effect. This makes flange bolts faster to install and more reliable in vibration-prone environments.
    Q Do flange bolts require a separate washer or nut?
    No. The integrated flange acts as a built-in washer, eliminating the need for a separate flat washer in most applications. This simplifies assembly, reduces part count, and lowers overall installation costs.
    Q What grade of flange bolt should I use for high-strength applications?
    For high-strength applications such as automotive drivetrains or heavy machinery, Grade 10.9 alloy steel flange bolts are commonly recommended. Grade 8.8 is suitable for general structural use, while Grade 4.8 is adequate for light-duty applications.
    Q Which surface treatment is best for outdoor or corrosive environments?
    Hot-dip galvanizing provides the thickest zinc coating and is best suited for heavy-duty outdoor or corrosive environments. Dacromet treatment offers excellent corrosion resistance without hydrogen embrittlement, making it ideal for high-strength bolts. Standard electroplated zinc galvanizing is suitable for general indoor or mild outdoor use.
    Q Are serrated flange bolts better than smooth flange bolts for vibration resistance?
    Yes. Serrated (toothed) flange bolts have radial tooth patterns on the flange surface that bite into the mating material, significantly increasing friction and resistance to loosening under vibration. Smooth flange bolts rely solely on clamping force, making them less effective in high-vibration environments such as engines or rail equipment.
    Q Can stainless steel flange bolts be used in high-temperature environments?
    Standard stainless steel grades such as A2-304 and A4-316 offer good corrosion resistance but have limited high-temperature strength. For elevated temperature applications, alloy steel or special high-temperature resistant grades should be selected. Always verify the temperature rating of the specific bolt material before use in heat-intensive environments.