Steel connectors are used for metal parts connecting steel components, wood components, and steel and wood components. Steel connectors mainly include rivets, bolts, high-strength bolts, welding rods, pivots (pins) and various nails.
Rivet refers to a cylindrical short rod with a semi-circular nail head at one end. It is inserted into each steel plate or section steel nail hole to be connected, and the protruding end is pressed or hammered into a second nail head. According to the shape of the rivet, it is divided into four types: semi-round head, high head, countersunk head, and half countersunk head. Round head rivets are commonly used in bridges and building structures. The rivets are made of steel No. 2 (ML2) and No. 3 (ML3) with better plasticity. The rivet connection has been gradually replaced by welding and high-strength bolts due to the labor-consuming, material-consuming, complicated riveting process, and easy loosening under dynamic loads.
Bolt is usually a cylindrical metal rod with a square or hexagonal head at one end and a thread at the other end, equipped with nuts and washers, which can fasten steel or steel-wood components together. The material is No. 3 steel or riveted No. 3 steel, which can be divided into two types: rough and refined bolts. The manufacture and installation requirements of refined bolts are relatively high, and they are rarely used at present. The surface of rough bolts does not require special processing and is mainly used for tension connection and installation connection.
High-strength bolts Using high-quality carbon structural steel or alloy structural steel, a special bolt with higher strength and a certain degree of plasticity and toughness obtained through heat treatment. A strong pre-tension must be applied during use. At present, China has two types of large hexagon head and torsion shear type. The commonly used models in civil engineering are M16, M20, M22, and M24. The maximum specifications can reach M30, and the performance level is divided into 10.9S and 8.8S. The materials are mainly 20MnTiB steel, 40B steel, 35VB steel, 45# steel and 35# steel. High-strength bolts are used for the connection of steel structures in industrial and civil buildings, highway and railway bridges, tower mast structures, pipeline supports, hoisting machinery, etc.
Welding Rod A rod-shaped metal strip that melts and fills the joints of welded parts during electric welding. It is coated with anti-oxidation (alloying, etc.) flux. According to the mechanical properties and chemical composition of the metal material to be welded, as well as the welding seam requirements and equipment process conditions, choose different types and models of electrodes. Commonly used structural steel electrodes are divided into four categories according to the deposited metal mechanical properties, welding power source, purpose and welding conditions: T42-0～T42-7; T50-0～T50-7; T55-X; T60-X. Electrode coatings are divided into titanium oxide type, titanium calcium oxide type, ilmenite type, iron oxide type, cellulose type, low hydrogen type and so on. Welding has been widely used in the production and installation of steel structures such as industrial and civil buildings, bridges, tower mast structures, and container equipment.
Pivot , also known as a pin, is a metal cylindrical connector used to connect two components that can rotate freely at the joint without pretensioning. One joint only needs one pivot, so the diameter is larger. Generally used on steel structures such as crane booms, arch hinges, and disassembly bridges.