Precision seamless pipe

Precision seamless pipes are often used in hydraulic components, pneumatic components, cylinders, hydraulic cylinders and other fields that need to withstand high pressure. They have excellent mechanical properties and dimensional accuracy, and are the preferred pipe material in many industries.

What is precision seamless pipe?

Precision Seamless Pipe is a kind of high-precision pipe material made by secondary processing (cold drawing, cold rolling or pickling and straightening) on the basis of ordinary seamless pipe. It is produced by two-high and three-high finishing mills. Compared with traditional hot-rolled or hot-drawn seamless tubes, precision seamless tubes have:
The tolerance for outer diameter and wall thickness is smaller, usually reaching the ± 0.01mm level.
The inner and outer surfaces are smoother, with Ra≤0.8μm.
The mechanical properties are more uniform, and the consistency between ultimate strength and yield strength is better.

Classification: Cold-drawn precision tubes vs. hot-rolled precision pipes

Cold-drawn precision pipes
Process flow: First, hot drawing is carried out, followed by annealing and pickling, then cold drawing and straightening, and finally fixed-length cutting.
Tolerance grade: The tolerance of outer diameter and wall thickness can be controlled within ±0.01-0.05 mm.
Surface roughness: Ra ≤ 0.4 μm.
Typical applications: It is used for automotive hydraulic pipes and pneumatic components with extremely high requirements for size and surface quality.

Hot-rolled precision pipes

Process flow: First, hot drawing, followed by annealing and pickling, then hot rolling (or bright annealing), and finally straightening and fixed-length cutting.
Tolerance grade: The tolerance for outer diameter and wall thickness is generally ±0.05-0.1 mm.
Surface roughness: Ra ≤ 0.8 μm.
Typical applications: Suitable for structural components and building supports, etc., where a smooth surface is required but the tolerance requirements are slightly loose.

The main advantages of precision seamless pipes

1. High dimensional accuracy and consistency: The cold drawing process ensures uniform outer diameter and wall thickness, eliminating the need for secondary cutting or grinding during assembly.
2. Excellent surface quality: The surface is smooth after bright annealing or pickling, free of oxide scale and cracks. With Ra≤0.4 μm, it can be directly used for high-precision assembly.
3. Enhance mechanical properties: The cold working hardening effect results in higher strength, and its fatigue resistance under cyclic loading is superior to that of ordinary seamless pipes.
4. Reduce post-processing costs: Due to high precision and good surface quality, secondary processing steps such as vibration grinding and polishing are reduced, shortening the production cycle.
5. Wide range of application fields: From automotive steering gears and hydraulic cylinders to furniture supports and medical equipment, its high-performance value can be demonstrated.

Industry standard comparison: GB/T 3639, EN 10305-1, ASTM A269

GB/T 3639 (Chinese national standard)

Scope of application: Cold-drawn precision seamless steel tubes for mechanical structures.
Key points: There are strict requirements for dimensional tolerance, surface quality and mechanical properties.

EN  10305-1 (eu standard)

Scope of application: Bright seamless steel pipes for fluid transportation.
Key points: Standardize the bright annealing process, chemical composition and mechanical property testing.

ASTM A269 (American Society for Testing and Materials standard)

Scope of application: Cold-drawn or cold-rolled precision seamless tubes for chemical, petrochemical and general purposes.
Key points: Pay attention to the chemical composition, mechanical properties and pressure resistance test requirements.

The precision of precision seamless tubes mainly depends on the specifications of the finishing mill. The more advanced the finishing mill, the higher the precision of the precision seamless tubes produced. CENTRAL STEEL has a complete precision seamless tube production line, which can achieve fully automatic production. Combined with fully automatic online size detection and straightening equipment, it can achieve ultra-high precision control of the tubes.

Read more : Precision seamless pipes vs ordinary seamless pipes