Segment bolt introduction

Segment bolts are divided into ring direction and longitudinal direction. In some designs, the circumferential and longitudinal specifications are the same. In some designs, two specifications are used in the circumferential and longitudinal directions, and even two strength levels. Generally speaking, the length of the circumferential segment bolts is longer than that of the longitudinal segment bolts.

In the construction of tunnels, there is a machine called shield machine that is engaged in starting and tunneling equipment. It has the functions of excavating and cutting soil, conveying soil ballast, and assembling tunnel lining. However, when the shield machine is used for tunnel lining, it is Assembled by several pieces of pipe, there is a kind of screw that plays the role of connection and fastening, and assembles to form a cylindrical pipe. The pipe piece is a cylindrical wall; during excavation, it can effectively control ground settlement and reduce the impact on ground buildings. It affects and does not affect water surface traffic when excavating underwater. The segments are combined to form a pipeline. This design is a linear or a certain arc-shaped fastening connector, which is a segment bolt. Segment bolts are divided into ring direction and longitudinal direction. In some designs, the circumferential and longitudinal specifications are the same. In some designs, two specifications are used in the circumferential and longitudinal directions, and even two strength levels. Generally speaking, the length of the circumferential segment bolts is longer than that of the longitudinal segment bolts.

Grade and material (Guide: The thread rolling process of high-strength bolts)

According to the application environment and different forces, the segment bolts, like other bolts and fasteners, are designed with different strength levels.

The commonly used ones are: 5.8, 6.8, and 8.8.

The corresponding production materials are: Q235, 45# steel, 40Cr and other materials.

Surface treatment of segment bolts

Surface treatment

The common surface treatments of segment bolts include: hot-dip galvanizing (hot-dip galvanizing), Dacromet (commonly known as zinc-based chromate), powder sherardizing, multiple composite powder sherardizing, etc. The quality of the surface treatment of segment bolts is very important. Because the segment bolts are installed underground, they play a role in connecting the segments. It is in a humid environment, which can easily cause corrosion of bolts and cause rust. Therefore, if the surface treatment of the bolt fails to meet the design requirements, causing the bolt to rust during use, the corrosion to the inside of the bolt will affect the mechanical properties and tensile strength of the bolt.

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