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What are the classifications of hot-dip galvanized bolts? Bolts: mechanical parts that are threaded cylindrical fasteners used in conjunction with nuts. A type of fastener consisting of a head and a screw (a cylinder with external threads), which must be used in conjunction with a nut to tighten and connect two parts that have holes. Classified by the way force is applied in the connection: there are ordinary types and those with hinge holes. Classified by head shape: there are hexagonal heads, round heads, square heads, countersunk heads, and so on. Among them, the hex head is commonly used. Blind heads are generally used in areas where a connection is required. The English name for a riding bolt is U-bolt; it is a non-standard component. Due to its U-shaped design, it is also known as a U-shaped bolt. It has threads at both ends that allow it to be connected to nuts. It is primarily used to secure tubular objects such as water pipes, or sheet-like components such as the leaf springs in cars. It is called a riding bolt because the way it secures objects resembles a person riding on a horse. Based on thread length, they are divided into full-thread and non-full-thread types. Based on the thread profile, they are divided into coarse-thread and fine-thread types; the coarse-thread type is not indicated in the bolt markings. Bolts are classified into eight grade categories based on their performance level: 3.6, 4.8, 5.6, 5.8, 8.8, 9.8, 10.9, and 12.9. Bolts of grade 8.8 or higher (including grade 8.8) are made of low-carbon alloy steel or medium-carbon steel and have undergone heat treatment (quenching + tempering); they are commonly referred to as high-strength bolts. Bolts of grades lower than 8.8 (excluding grade 8.8) are generally known as ordinary bolts. According to their manufacturing precision, ordinary bolts can be divided into three grades: A, B, and C. Grades A and B are precision bolts, while grade C is a coarse-grained bolt. For connection bolts used in steel structures, unless otherwise specified, they are generally ordinary rough-finished Class C bolts. The methods for processing bolts at different grades vary, and the corresponding processing techniques are as follows: ① The shanks of bolts of grades A and B are manufactured using lathes, resulting in a smooth surface and precise dimensions; their material strength grade is 8.8. These bolts require complex manufacturing and installation processes, and they are relatively expensive, which is why they are rarely used; ② Bolts of grade C are made from untreated round steel, with less precise dimensions, and their material strength grade is either 4.6 or 4.8. Shear connections experience significant deformation, but they are easy to install and have low production costs; they are often used for tensile connections or as temporary fixations during installation.