black bolt in steel structure

A hex washer head bolt is essentially a threaded rod with a hexagonal head, providing a larger surface area than a standard hex bolt. The integrated washer portion of the bolt serves two primary functions. Firstly, it distributes the clamping force over a wider area, preventing damage to the material being fastened and reducing the risk of loosening due to uneven pressure. Secondly, it increases the friction between the bolt and the surface, enhancing the holding power and ensuring a secure connection.

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Metal expansion nuts, often referred to as expansion anchors or expansion inserts, are specialized fasteners that expand when a bolt or screw is threaded into them. They typically consist of a cylindrical body with slits along its length or an expandable design that facilitates outward expansion. The main purpose of these nuts is to create a secure grip within a substrate, such as concrete, wood, or metal, thereby preventing loosening due to vibrational forces, temperature fluctuations, or stress.


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