Flange Bolts – Flange Screws – Hex Flange Bolts M5->M16

19/04/2022 | Views: 1606

A flange bolt is a type of threaded fastener that combines a bolt with a built-in washer-like flange under the bolt head. This flange serves several purposes, making flange bolts particularly useful in certain applications.


Here are the key characteristics and functions of flange bolts:

1. Flange Design: The most distinctive feature of a flange bolt is the integrated flange, which is a flat, washer-like surface beneath the bolt head. This flange is wider than the bolt’s diameter.

2. Distribution of Load: The flange serves to distribute the load over a larger surface area. This can help prevent the bolt from sinking into soft materials or damaging the surface it’s fastened to.

3. Reduced Risk of Over-Tightening: The flange also acts as a built-in washer, reducing the risk of over-tightening the bolt, which can occur with standard bolts and separate washers.

4. Vibration Resistance: Flange bolts are often used in applications where vibration is a concern. The flange helps to lock the bolt securely in place and prevents it from loosening due to vibration.

5. Serrated Flanges: Some flange bolts have serrations (small, raised ridges or teeth) on the underside of the flange. These serrations create additional grip when the bolt is tightened and can enhance the bolt’s resistance to loosening.

Other names: flange screws, hex flange bolts, frame bolts, flanged hex head bolts, serrated flange bolts, hex washer head bolts



A flange bolt consists of two main components: the bolt and the integrated flange. Here’s a breakdown of the structure of a typical flange bolt:

1. Bolt Head: The bolt head is the top part of the bolt. It can be various shapes, including hexagonal (hex head) or socket head (for use with Allen wrenches or hex keys). The choice of head shape depends on the specific design and application requirements.

2. Flange: The flange is an integral part of the bolt, located just below the bolt head. It has a flat, washer-like shape and is wider than the bolt’s shank. The purpose of the flange is to distribute the load over a larger surface area when the bolt is tightened.

3. Shank: The shank is the straight, cylindrical portion of the bolt that extends from the flange to the threaded end. This section of the bolt goes through the materials being fastened together.

4. Threaded End: The threaded end of the bolt is the portion with screw threads. This is the part that engages with a nut or threaded hole in the material to create a secure connection.

5. Thread Length: The length of the threaded portion can vary depending on the bolt’s size and purpose. It determines how deep the bolt can penetrate into the material or how many threads will engage with a nut or threaded hole.

6. Serrations (Optional): Some flange bolts have serrations or raised ridges on the underside of the flange. These serrations enhance grip and help prevent loosening due to vibration or movement.

7. Material and Finish: Flange bolts can be made from various materials, such as steel, stainless steel, or other alloys, depending on the application’s requirements. They may also have different surface finishes, such as zinc plating or galvanization, to enhance corrosion resistance.


  • Diameter (M): M5-> M20 mm
  • Length (L): 10 ~ 240 mm
  • ISO Grade: 4.8 / 5.6 / 8.8/ 10.9 /12.9 / Gr5, Gr8
  • Material: Carbon steel; Stainless steel 316/304/201
  • Lace type: Mezzanine lace, transparent lace.
  • Surface Finish: Black (plain/black); Electro-zinc-plated, Hot dip galvanized, Dacromet plated, Stainless steel 316/304/201
  • Standard: DIN 6921, GB5787, GB 5789, ASTM, IFI1111





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