U-bolts, also commonly known as U-shaped bolts or saddle bolts, are general-purpose fasteners that are extremely widely used in the industrial and construction sectors. With their distinctive U-shaped bend and threaded ends, they can be used in conjunction with nuts and washers to secure components. Their primary function is to fix components such as pipes, profiles and equipment bases in place, preventing the connected parts from shifting, loosening or coming loose. Thanks to their simple structure, high load-bearing capacity and wide adaptability, they have become an indispensable basic component in various engineering and mechanical assembly applications.
Structure and Principle
The U-shaped wire features a standard U-shaped structure, comprising a curved base formed from a single bend, two vertical wires and a threaded top section. It is manufactured as a single, seamless piece, ensuring exceptional structural stability. Its operating principle is very simple: during use, the U-shaped opening is clipped onto the outer surface of the tubular, bar-shaped or block-shaped component to be secured. Once fitted against the mounting base, washers are fitted at both threaded ends and the nuts are tightened. Utilising the tensile force of the threaded rods and the clamping force of the curved structure, the component is securely locked in place, achieving positional fixation, vibration damping and anti-displacement effects. Furthermore, the bending radius of the U-shaped wire, the length of the threaded rod and the thread specifications can all be customised as required, enabling adaptation to workpieces of various dimensions.

1. Classification by Shape and Structure
   Round U-shaped wires are suitable for curved components such as circular pipes, round steel bars and cables, and are the most commonly used standard type;
   Square U-shaped wires are specifically designed for square components such as square tubes, rectangular sections and steel structural purlins; they offer a better fit and more secure fastening, and are frequently used in photovoltaic mounting systems and steel structure construction projects.
2. Classification by Surface Treatment
   Black annealed U-shaped wires: these are not galvanised and retain the natural colour of the steel; they offer good toughness and are cost-effective, making them suitable for temporary fastening in dry, non-corrosive indoor environments;
   Electro-galvanised U-shaped wire features a uniform zinc coating and a smooth finish, with moderate rust resistance and excellent value for money; it is commonly used for indoor equipment assembly and general pipework fastening;
   Hot-dip galvanised U-shaped wire has a thick zinc coating with extremely strong adhesion; it is resistant to acids and alkalis, corrosion-resistant, and withstands wind, rain and exposure to the sun, making it suitable for harsh outdoor environments, including open-air, damp and highly corrosive conditions;
   Polished stainless steel U-shaped wire: with a smooth, burr-free surface and no need for additional plating, it offers top-tier corrosion resistance.
3. Classification by Material
   Carbon steel U-shaped wire，carbon steel is primarily composed of medium- and low-carbon steel and alloy steel; it offers high hardness and strong tensile strength, providing excellent value for money and meeting the requirements of the vast majority of standard engineering applications;
   Stainless steel U-shaped wire，stainless steel is commonly available in grades 304, 316 and 316L; it offers high toughness, fatigue resistance, corrosion resistance and is rust-free, and is frequently used in specialised applications such as marine vessels, chemical equipment and coastal engineering projects.

U-shaped wire is used across a wide range of sectors, including construction, industry, new energy and transport, and serves as a core fastening component in numerous scenarios. Typical applications are as follows: