ST52 Bored Tube

Material Properties of ST52 Steel

ST52 steel (DIN 2391 / EN 1.0570 S355) is a high-quality structural steel with an excellent balance of strength and ductility. It offers outstanding machinability, weldability, and impact resistance, making it ideal for hydraulic components.

Chemical Composition (Typical %):

Mechanical Properties:

The combination of high yield strength and excellent ductility allows the ST52 bored tube to withstand high pressure, vibration, and dynamic loads without cracking or deformation.

Manufacturing Process of ST52 Bored Tube

Producing an ST52 bored tube requires precision machining and strict quality control to achieve both strength and surface accuracy.

Step 1: Raw Material Preparation

High-quality ST52 seamless steel pipes are selected as the base material. The tubes are inspected for surface defects, dimensional uniformity, and chemical composition before processing.

Step 2: Boring Process

The inner bore is processed using deep-hole boring machines that remove excess material from the tube’s inner wall. This process ensures accurate inner diameters, high roundness, and precise wall thickness.

Step 3: Heat Treatment (Optional)

Depending on customer requirements, the tubes can undergo quenching and tempering (Q+T) to improve hardness, tensile strength, and fatigue resistance for high-pressure hydraulic systems.

Step 4: Surface Finishing

After boring, the inner surface is finished to a fine surface roughness of Ra ≤ 0.8 μm, which reduces friction and improves seal life in hydraulic applications.

Step 5: Inspection and Testing

Each ST52 bored tube is subjected to rigorous inspection, including:

Ultrasonic flaw detection

Dimensional and straightness testing

Mechanical property verification

Surface roughness and hardness measurement

This ensures that every tube meets strict quality standards before delivery.

Dimensional Range and Technical Specifications

Custom dimensions and machining (such as grooving, porting, or flange welding) are available according to specific engineering needs.

Key Advantages of ST52 Bored Tube

5.1. High Strength and Load Capacity

ST52 steel has superior mechanical strength, allowing bored tubes to perform reliably under high internal pressure and heavy load conditions. It ensures structural stability in large hydraulic systems.

5.2. Excellent Inner Surface Quality

The precision boring process achieves a highly smooth bore, minimizing piston wear and improving hydraulic cylinder sealing performance.

5.3. Dimensional Accuracy and Straightness

The tight tolerance and controlled machining ensure consistent straightness and roundness across the entire tube length, essential for precise hydraulic cylinder assembly.

5.4. Enhanced Machinability

ST52 material is easily machinable and weldable, making it suitable for secondary processing like port machining, thread cutting, or custom cylinder design.

5.5. Long Service Life

Due to its excellent fatigue resistance and anti-corrosion performance (after protective coating or plating), the tube maintains stable operation over long service cycles.

5.6. Cost Efficiency

Compared to honed tubes or skived & roller burnished tubes, bored tubes are more economical for large-diameter or heavy-duty cylinders that require structural strength rather than ultra-fine precision.

Applications of ST52 Bored Tube

ST52 bored tubes are widely used in industries requiring high-pressure fluid power systems. Their strength and machinability make them ideal for both industrial and mobile hydraulic equipment.

Primary Application Areas:

Mining Machinery: Dump trucks, drilling rigs, and loaders

Construction Equipment: Excavators, bulldozers, and cranes

These applications demand a robust material capable of withstanding high stress, vibration, and long working cycles, which ST52 bored tubes fully meet.

Quality Control and Testing

EASTAI applies strict inspection and testing procedures to guarantee product reliability and consistency.

Quality Assurance Includes:

100% ultrasonic flaw detection

Dimensional tolerance verification

Hardness and tensile testing

Surface finish inspection

All test results are documented and traceable to ensure transparency and confidence in product quality.

Packaging and Delivery

Each ST52 bored tube is carefully packed to prevent corrosion and mechanical damage during shipment.

Standard Packaging:

Anti-rust oil coating on the inner and outer surfaces

Plastic film and woven fabric wrapping

Wooden or steel-frame crates for export

Fumigation-free packaging and pallet options available

EASTAI maintains a strong stock capability of over 10,000 tons, ensuring fast delivery — typically within 7 to 15 days for standard dimensions.

Why Choose EASTAI as Your Bored Tube Supplier

Since 2002, EASTAI has been a professional manufacturer and supplier of hydraulic cylinder materials, specializing in honed tubes, skived and roller burnished tubes, chrome plated rods, and bored tubes.

Our Core Strengths:

Over 18 years of manufacturing experience

GL (Germanischer Lloyd) Approval of Material Manufacturers (AMM)

Factory area of more than 8,000 m²

Comprehensive inventory and fast delivery

Advanced boring and straightening machines

Full material traceability and inspection reports

Excellent after-sales service and technical support

EASTAI provides one-stop hydraulic tube solutions for global customers in over 50 countries, trusted by OEMs and engineering companies worldwide.