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DIN 6921 Flange Bolts - High-Quality Bolts from China Suppliers & Factory for Optimal Performance and Durability
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DIN 6921 Flange Bolts - High-Quality Bolts from China Suppliers & Factory for Optimal Performance and Durability

Explore our high-quality flange bolts, available in various grades including 4.8, 8.8, 10.9, and 12.9. These bolts are manufactured from durable materials such as Q235, 35K, 45K, 40Cr, 20Mn TiB, 35CrMo, and 42CrMo. Our surface treatments include options like blackened, electrogalvanized, Dacromet, hot-dip galvanized, and traditional galvanized finishes. As a leading factory and supplier in China, we provide integrated flange bolts that feature a hexagonal head combined with a flange plate, ensuring a sturdy connection for any application. These bolts require a nut for secure fastening and are ideal for joining parts through two aligned holes. Trust our China factory for the best in quality and reliability!

    Surface treatment process PRODUCTS

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    Flange bolt: A flange bolt is an integral bolt composed of a hexagonal head and a flange plate (the gasket below the hexagon and the hexagon are fixed together) and a screw (a cylindrical body with external threads). It needs to be matched with a nut and used to tighten the parts connecting two through holes. Therefore, bolt connection is a detachable connection.

    Classification PRODUCTS

    • Hexagonal head type: One is flat headed, and the other is concave headed.
    • Surface color category: According to different needs, the surface is coated with white, military green, colored yellow, and corrosion-resistant Dacromet.
    • Category of flange: Depending on the location of the flange bolts used, the size requirements for the flange vary. There are also flat bottomed and toothed types, with toothed ones providing anti slip function.
    • According to force distribution: There are ordinary and hinged holes. The flange bolts used for hinged holes should match the size of the holes and be used when subjected to lateral forces.

    In addition, to meet the need for locking after installation, there are holes in the rod, which can prevent the bolt from loosening when subjected to vibration.

    Some flange bolts need to be made on the bare rod part without threads, called thin rod flange bolts. This type of flange bolt is beneficial for connecting under variable forces.

    Note: Commonly used national standard numbers in the market, GB5789 (large head) and GB16674 replace GB5787 (small head).

    Purpose PRODUCTS

    The flange bolt is composed of a hexagonal head and a flange plate, and its "support area to stress area ratio" is greater than that of ordinary bolts. Therefore, this type of bolt can withstand higher pre tightening force and has good anti loosening performance. Therefore, it is widely used in automotive engines, heavy machinery and other products.

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    Frequently Asked Questions (FAQ)

    What is a flange bolt?
    A flange bolt is an integral fastener consisting of a hexagonal head, a flange plate (which functions as a fixed gasket below the head), and a threaded screw. It is paired with a nut to secure components through two aligned holes.
    What surface treatments are available for flange bolts?
    Depending on the specific requirements, flange bolts can be coated in white, military green, colored yellow, or treated with corrosion-resistant Dacromet.
    Why do some flange bolts have teeth?
    Flange plates come in flat-bottomed and toothed types. Toothed flange bolts are designed to provide an anti-slip function, helping to prevent loosening under vibration.
    When should hinged hole flange bolts be used?
    Hinged hole flange bolts are designed to match the exact size of the joint holes and are used specifically when the connection needs to withstand lateral forces.
    Why are flange bolts preferred in automotive engines and heavy machinery?
    Because the ratio of their support area to stress area is greater than that of ordinary bolts, flange bolts can withstand higher pre-tightening force and offer superior anti-loosening performance.