Fasteners, as commonly used parts, should be familiar to everyone. Today, we will introduce them from four aspects: classification of fasteners, identification and inspection of threads, material requirements, heat treatment requirements, and mechanical performance requirements of bolts, screws, and studs, as well as types and structures of steel structure bolts. It is full of practical knowledge and worth collecting.

1、 Classification of fasteners

1. What is a fastener?

Fasteners are a general term for a type of mechanical component used to securely connect two or more parts (or components) into a whole. Also known as standard parts in the market.

2. It usually includes the following 12 types of parts

Bolts, studs, screws, nuts, self tapping screws, wood screws, washers, retaining rings, pins, rivets, assemblies and connecting pairs, welding nails.

(1) Bolt: A type of fastener consisting of a head and a screw (a cylindrical body with external threads), which needs to be matched with a nut to securely connect two parts with through holes. This type of connection is called bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

As shown in the following figure: