Precautions for purchasing hydraulic tubes

With the development of science and technology, hydraulic technology has been widely used in various fields. As an important component of hydraulic systems, the quality and performance of hydraulic tubes have a great impact on the stability and safety of the system. Therefore, in the design and maintenance of hydraulic systems, the purchase of hydraulic tubes is a crucial step. This article will introduce the relevant knowledge and precautions for purchasing hydraulic tubes.

Types of hydraulic tubes:

There are many types of hydraulic tubes, including carbon steel tubes (seamless tubes and welded tubes), stainless steel tubes (such as 304, 316), copper tubes, etc. Among them, carbon steel seamless tubes are one of the commonly used pipes in hydraulic systems. They have smooth inner walls, high tensile strength, and strong pressure bearing capacity. They are suitable for high-pressure and large-flow hydraulic systems.

Stainless steel tubes have good corrosion resistance and are suitable for precision machinery and high-temperature and high-pressure environments.
Copper tubes have good thermal conductivity and plasticity, and are suitable for low-temperature environments and systems with high precision requirements.

Specifications of hydraulic pipes:

Specifications of hydraulic pipes include pipe diameter (inner diameter and outer diameter), wall thickness, length, etc. Common pipe diameters are 6mm, 8mm, 10mm, 12mm, etc. The wall thickness is generally about 1mm, and the length is generally 4m. When selecting the specifications of hydraulic pipes, it is necessary to comprehensively consider factors such as the working pressure, flow, medium (oil/water/chemicals) and working temperature of the hydraulic system.

Key points for purchasing hydraulic tubes:

1. Material requirements
The quality of hydraulic pipes is directly related to the stability and safety of the system. Therefore, reliable pipes of suitable materials must be selected when purchasing.
Commonly used carbon steel seamless steel pipes and welded steel pipes should be selected from pipes that meet standards (such as ASTM A53, ASTM A106), stainless steel pipes should be selected from 316L ss pipes, and copper pipes should be selected from T2 pipes. Corrosion-resistant and pressure-resistant materials need to be selected according to the pressure of the hydraulic system and the medium (oil/water/chemicals).

2. Specifications and dimensional accuracy
The selection of pipe diameter and wall thickness of hydraulic pipes should be determined according to the working pressure and flow of the system. The dimensional accuracy also has a great impact on the stability and safety of the system. Therefore, the inner diameter, outer diameter and wall thickness of the hydraulic pipe must meet the standards (such as ISO 3304, DIN 2391) to ensure compatibility with the joints and ensure the normal operation and safety of the system.

3. Surface quality
The surface of the hydraulic pipe should be flat and smooth, without obvious scratches, bumps, cracks, rust and other defects. The galvanized pipe needs a uniform zinc layer without shedding, otherwise it is easy to cause pipeline leakage and failure.

4. Process standards
Preferably choose cold-drawn or precision-rolled seamless steel pipes to avoid weld defects (welded steel pipes are only suitable for low-pressure scenarios).

5. Quality inspection
Sampling is carried out for hydrostatic testing, eddy current testing or ultrasonic testing to verify the sealing and pressure resistance.

6. Supplier reputation
The quality and performance of hydraulic pipes are not only related to the pipe itself, but also to the reputation and service of the supplier.

Industry reputation: give priority to manufacturers with experience in supporting hydraulic systems, and refer to past customer reviews.

Production capacity: confirm whether the supplier has a complete production line (such as cold drawing and heat treatment equipment) to avoid resale traders.

After-sales service: clarify the return and exchange policy for quality issues and the technical support response time.

Manufacturers should provide qualification documents: require suppliers to provide material reports (such as MTC), third-party inspection certificates (such as SGS), and production should comply with standards (such as ASTM A106, EN 10305), etc.

Others:

Special needs:
Customization requirements: non-standard sizes or special coatings (such as phosphating, chrome plating) require technical details to be communicated in advance.

Environmental compliance: Exports to the EU must comply with the RoHS directive, and food machinery requires FDA certification.

Cost and delivery:
Price comparison: comprehensively compare FOB/CIF quotations, and pay attention to additional costs (such as tariffs, transportation insurance).
Delivery cycle: confirm that the production cycle matches the project schedule to avoid the increase in costs of emergency air transportation.
Bulk discounts: bulk purchases can negotiate ladder prices, but inventory costs need to be balanced.

Contract terms:
Clear acceptance criteria: specify sampling ratios and methods for handling defective products.
Breach of contract terms: compensation for delayed delivery or substandard quality.

Installation and maintenance of hydraulic tubes:

1. Installation
The installation of hydraulic pipes should be carried out strictly in accordance with design requirements. Appropriate joints should be used at pipe joints. The pipes should be kept clean and smooth, and there should be no defects such as deformation and cracks.

2. Maintenance
The maintenance of hydraulic pipes includes regular inspection, cleaning and replacement.

Extended information:

What is the difference between hydraulic tubes and mechanical tubes?

Hydraulic tubes and mechanical tubes have their own focuses in industrial applications, but they may be used interchangeably in some scenarios. Hydraulic pipes are designed specifically for hydraulic systems and are used to transmit high-pressure liquids (such as hydraulic oil and emulsions). They are subject to periodic pressure fluctuations and require strong resistance to high pressure and sealing. Mechanical pipes are mainly used in non-fluid transmission scenarios such as support, transmission, and protection, requiring high strength and dimensional accuracy.

Read more: Cold Drawn Seamless Tube for Mechanical & Hydraulic