I. Steel Design In the fastener manufacturing, it is an important link to correctly select the fastener material, because the performance of the fastener is closely related to its material.
Second, during spheroidizing (softening) annealing, countersunk head screws and hexagon socket head bolts are produced by cold heading process, and the original structure of steel will directly affect the formability during cold heading.
Third, peeling and derusting, the process of removing scale from cold heading steel wire rod is peeling and derusting, and there are two methods: mechanical derusting and chemical pickling.
Fourth, drawing, the drawing process has two purposes, one is to change the size of raw materials; Secondly, fasteners can obtain basic mechanical properties through deformation and strengthening.
5. Cold forging. Usually, the bolt head is formed by cold upsetting plastic processing. Compared with cutting processing, the metal fiber (metal wire) is continuous along the shape of the product without cutting in the middle, thus improving the strength of the product, especially the excellent mechanical properties.
Six, thread processing, bolt thread generally adopts cold working, so that the thread blank within a certain diameter range passes through the rubbing (rolling) wire plate (die), and the thread is formed by the pressure of the wire plate (rolling die).
Seven, heat treatment, high strength fasteners should be tempered according to technical requirements.
Extended information: 1. When manufacturing fasteners in steel structure design, the correct selection of fastener materials is an important link, because the performance of fasteners is closely related to their materials. Improper or incorrect material selection may lead to unsatisfactory performance, shortened service life, even accidents or processing difficulties, and high manufacturing costs, so the selection of fastener materials is a very important link.
Second, during spheroidizing (softening) annealing, countersunk head screws and hexagon socket head bolts are produced by cold heading process, and the original structure of steel will directly affect the formability during cold heading. In the process of cold heading, the plastic deformation of local area can reach 60%-80%, so the steel must have good plasticity.
Third, peeling and derusting, the process of removing scale from cold heading steel wire rod is peeling and derusting, and there are two methods: mechanical derusting and chemical pickling. Using mechanical descaling instead of chemical pickling process of wire rod not only improves productivity, but also reduces environmental pollution.
Fourth, drawing, the drawing process has two purposes, one is to change the size of raw materials; Secondly, fasteners can obtain basic mechanical properties through deformation and strengthening.
5. Cold forging. Usually, the bolt head is formed by cold upsetting plastic processing. Compared with cutting processing, the metal fiber (metal wire) is continuous along the shape of the product without cutting in the middle, thus improving the strength of the product, especially the excellent mechanical properties. The cold heading forming process includes cutting forming, single-click and double-click cold heading and multi-station automatic cold heading.
Six, thread processing, bolt thread generally adopts cold working, so that the thread blank within a certain diameter range passes through the rubbing (rolling) wire plate (die), and the thread is formed by the pressure of the wire plate (rolling die). The plastic streamline of the threaded part will not be cut off, and products with increased strength, high precision and uniform quality can be obtained, so it is widely used.
Seven, heat treatment, high strength fasteners should be tempered according to technical requirements. The purpose of heat treatment and tempering is to improve the comprehensive mechanical properties of fasteners to meet the specified tensile strength and yield ratio of products.
Reference source Bolt- Baidu Encyclopedia