Hydraulic rigid pipes are indispensable key elements in hydraulic systems.

Hydraulic rigid pipes are indispensable key elements in hydraulic systems, used to transmit hydraulic oil pressure and convey various media. These rigid pipes are mostly made of metal materials such as steel, copper, and aluminum. With their excellent rigidity and pressure resistance, they lay a solid foundation for the stable operation of the system.

In terms of structural composition, hydraulic rigid pipes mainly consist of the pipe body, joints, and crimped joints. The pipe body is generally made of high-strength steel, and its inner wall is polished very smooth, which can effectively reduce pressure loss. The joint part is usually made of copper alloy or stainless steel, which is responsible for connecting the pipe body and hydraulic components. The crimped joint is responsible for firmly fixing the pipe on the hydraulic components.

A large number of connecting rigid pipes are laid in the hydraulic system. Once these pipelines are damaged or leak oil, the consequences are considerable. In mild cases, it will cause environmental pollution and interfere with the normal function of the system. In severe cases, it may even threaten personal safety and equipment stability. Therefore, in the process of hydraulic equipment transformation, the selection, processing, and installation of hydraulic rigid pipes are extremely critical links. Only by mastering scientific and reasonable methods can the long-term and stable operation of the hydraulic system be ensured. So, how to choose the appropriate hydraulic rigid pipes? 1. Material Selection The determination of hydraulic rigid pipe materials depends on specific applications and should be selected according to system pressure, flow rate, and operating conditions.   Steel Pipes: They have the characteristics of high strength, high pressure resistance, and good wear resistance, and are suitable for high-pressure and high-load hydraulic systems. In general, seamless steel pipes are used for piping in medium and high-pressure systems. Due to their high strength, low cost, and easy realization of leak-free connections, they are widely used in hydraulic systems.   Copper Pipes: They feature high thermal conductivity, corrosion resistance, good flexibility, and non-magnetism. The good corrosion resistance of copper pipes can ensure the cleanliness of the oil and prevent impurities generated by corrosion from affecting the system accuracy. Their high thermal conductivity helps to dissipate heat quickly, maintain stable oil temperature, and ensure stable system performance. The non-magnetic feature also avoids magnetic field interference with precision instruments, making them commonly used in systems with high requirements for oil cleanliness and harsh working environments.   Aluminum Pipes: They are characterized by light weight, good corrosion resistance, excellent thermal conductivity, good processing performance, and beautiful appearance. Aluminum has a low density, so aluminum pipes are significantly lighter than steel rigid pipes, making the installation and handling of hydraulic rigid pipe assemblies more convenient and labor-saving. Aluminum easily reacts with oxygen in the air to form a dense aluminum oxide film on the surface, which can effectively prevent further oxidation of the internal aluminum. They are easy to process and form and have good thermal conductivity, so they are often used in systems with high requirements for weight and mobility.  When selecting the material of hydraulic rigid pipes, various factors such as working pressure, corrosiveness of the working environment, temperature, and cost need to be comprehensively considered to select suitable materials and ensure the safe and reliable operation of the hydraulic system. If the rigid pipe needs to be bent, it is necessary to ensure that the selected pipe material has sufficient flexibility to achieve the required bending radius without affecting the performance of the pipe.   2. Size Selection The key dimensions of hydraulic rigid pipes are the outer diameter and wall thickness.   Outer Diameter: It directly determines the internal channel cross-sectional area of the hydraulic rigid pipe, thereby affecting the flow capacity of the hydraulic oil. The larger the outer diameter, the greater the oil flow that can be accommodated in the pipeline, which can meet the needs of large-flow hydraulic systems. Moreover, the outer diameter is a key dimension for matching with various connecting components (such as joints, flanges, etc.). Different connection methods and specifications have specific requirements for the outer diameter of the rigid pipe, which must be precisely matched to ensure the tightness and reliability of the connection.   Wall Thickness: It is an important factor affecting the pressure-bearing capacity of hydraulic rigid pipes. The larger the wall thickness, the higher the hydraulic pressure that the rigid pipe can withstand. In high-pressure hydraulic systems, rigid pipes with larger wall thicknesses are required to withstand extremely high pressures, prevent pipeline rupture or deformation, and ensure the safe operation of the system.  

Appropriate wall thickness can ensure that the hydraulic rigid pipe has sufficient strength and rigidity to resist the impact force, vibration, and external environmental factors (such as mechanical collision, pressure fluctuation, etc.) generated during the flow of hydraulic oil. If the wall thickness is too thin, the rigid pipe may deform, rupture, or suffer fatigue damage under these forces, affecting the stability and service life of the hydraulic system. Excessive wall thickness may lead to material waste, increased costs, and excessive pipeline weight. Therefore, the appropriate outer diameter and wall thickness should be calculated and determined according to the working pressure and strength requirements.   3. Connection Methods Reliable connection methods usually include compression fittings, flared connections, and welding to ensure the tightness and reliability of the pipeline.   Compression Fitting Connection: It uses the compression ring to embed the surface of the pipeline when the nut is tightened to form multiple sealing lines. This connection method is easy to install, has strong sealing performance, and can adapt to a certain vibration environment. It is widely used in industrial equipment and vehicle hydraulic systems.   Flared Connection: It realizes a tight connection by expanding the pipe orifice into a specific shape and matching it with a nut and pipe fitting. It has a simple structure and is easy to disassemble, suitable for medium and low-pressure hydraulic systems. However, it has certain requirements for the material and wall thickness of the pipe, otherwise, cracks are likely to occur during the flaring process.  Welding Connection: It forms an integrated joint by fusing metals at high temperature, capable of withstanding extremely high pressures and harsh working conditions. This method is often used in fields with stringent sealing requirements, such as aerospace and heavy machinery. However, the welding process imposes strict demands on operational techniques. Once issues like insufficient welding or air holes occur, they will lay hidden dangers of leakage. 

The selection of hydraulic rigid pipes needs to be carefully considered from three dimensions: material, size, and connection method.   Material Selection: It is necessary to balance pressure bearing, environmental adaptability, and cost control. For example, seamless steel pipes are preferred for high-pressure and heavy-load working conditions, non-magnetic copper pipes are suitable for precision instruments, and aluminum pipes are inclined to lightweight equipment.   Size Parameters: They need to be based on flow calculation and pressure check. While ensuring efficient oil transmission, the safety and economy should be balanced through reasonable wall thickness design.   Determination of Connection Methods: It should be based on the complexity of working conditions. Compression fitting connections have more advantages in vibration environments, flared connections are suitable for medium and low-pressure systems, and welding processes must be relied on in extreme working conditions.   Only by organically combining these three aspects and establishing a complete selection system from theoretical calculation to practical application can the hydraulic rigid pipes be ensured to play a stable and reliable transmission role in the system and provide a solid guarantee for the efficient operation of industrial equipment.