Honing Tube

Quilting and Grinding tube is a mechanical processing technology that uses oil stones on the grinding head to perform reciprocating high-speed grinding and finishing on the inner hole of the cold drawn tube, so as to achieve the required tolerance size and surface roughness requirements for the inner hole. According to customer requirements for grinding and processing, the tolerance range can be achieved (such as H7, H8, H9, etc.), the roughness can reach Ra0.4, the ellipticity can reach 3-5 threads, and the longest length can reach 8m.

Honed tubes, also known as honed pipes or hydraulic cylinder tubes, are precision seamless steel tubes that have undergone an internal honing process. This finishing technique is critical for applications requiring exceptionally smooth internal surfaces, superior dimensional accuracy, and high-pressure resistance. They are the fundamental component in the manufacturing of hydraulic and pneumatic cylinders, serving as the barrel in which the piston reciprocates.

The defining characteristic of these tubes is the honing process. After initial drawing or extrusion, the tube's inner diameter (ID) is subjected to honing. This is an abrasive machining process that uses a honing tool with expanding abrasive stones to remove a minimal amount of material. The tool rotates and reciprocates simultaneously within the tube, creating a precise cross-hatch surface pattern.

This process achieves two primary goals:

Extreme Surface Finish: It produces an incredibly smooth internal surface with a very low roughness average (Ra). Typical values range from Ra 0.2 µm to Ra 0.4 µm, minimizing friction and wear on seals and pistons.

Precise Geometrical Accuracy: It ensures excellent straightness, roundness, and dimensional consistency along the entire length of the tube. This eliminates deviations that could cause leaks, inefficiency, or premature failure.

Characteristics and Advantages

• Low Friction Surface: The mirror-like finish significantly reduces friction between the piston seals and the tube wall, enhancing efficiency and service life.
• Excellent Wear Resistance: The smooth surface is less prone to abrasion, protecting both the tube and the sealing elements.
• High Pressure Resistance: The consistent wall thickness and absence of internal imperfections allow them to withstand high operating pressures without deformation or failure.
• Reliable Seal Performance: The precise geometry and fine surface finish ensure perfect sealing, preventing fluid leakage and maintaining system pressure.
• Optimized Oil Retention: The characteristic cross-hatch pattern helps retain lubrication oil, further reducing wear and ensuring smooth operation.

Common Materials

Honed tubes are typically manufactured from:

• Carbon Steel: The most common choice, such as ST52 (E355), AISI 1020, AISI 1045. Offers a great balance of strength, hardness, and cost-effectiveness.
• Alloy Steel: Used for higher strength requirements, e.g., ST52.3, 4130, 4140.
• Stainless Steel: For applications requiring corrosion resistance, such as 304/304L or 316/316L grades.

Applications

Honed tubes are indispensable in industries where reliable linear motion and force transmission are paramount. Key applications include:

• hydraulic cylinders: (e.g., in construction equipment, excavators, bulldozers, and forklifts)
• Pneumatic Cylinders: (e.g., in manufacturing automation and packaging machinery)
• Automotive Shock Absorbers
• Plastic Injection Molding Machines
• Agricultural Machinery
• Material Handling Equipment