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Views: 0 Author: Site Editor Publish Time: 2026-04-07 Origin: Site
In modern hydraulic systems, engineering machinery, industrial automation, and heavy-duty equipment, the quality of the inner surface of a steel tube directly affects sealing performance, wear resistance, service life, and overall operating stability. That is why deep hole honing and extrusion processing for precision steel tubes has become increasingly important in high-performance industrial applications.It is widely used for the fine finishing of internal bores.
At Changzhou Fengdie Metal Technology Co., Ltd, we focus on supplying high-quality hydraulic cylinder tube precision steel tubes, honed tubes, and customized inner bore processing solutions for customers who require reliable dimensional accuracy, excellent surface finish, and stable product consistency.
Whether you are sourcing hydraulic cylinder tubes, precision honed pipes, or high-grade steel tubes for demanding industrial projects, understanding the benefits of deep hole honing and extrusion can help you choose the right solution for your business.
What Is Deep Hole Honing for Precision Hydraulic Cylinder Tube Steel Tubes?
Deep hole extrusion is one of the effective methods for surface finishing and strengthening of small inner bores. This process can achieve IT5–IT6 dimensional accuracy and an internal surface roughness of Ra 1.6–0.21 μm. It also offers the advantages of relatively simple tooling and lower machine accuracy requirements. Deep hole extrusion is suitable for bore diameters ranging from Φ2 mm to Φ50 mm, and it features high machining efficiency. Its main functions include sizing the bore accurately, smoothing the inner surface, and strengthening the surface layer.
1. Extrusion Tools
Extrusion tools are usually made of tool steel, alloy tool steel, high-speed steel, or cemented carbide. For the first three materials, the hardness after heat treatment normally reaches HRC 60–66, and the finished tool surface roughness should be less than Ra 0.05 μm. In practical production, commonly used tool structures include conical and spherical extrusion heads. The front taper angle α and rear taper angle α′ are generally 4°–5°. The land width b is usually 1.5–2 mm, or it can be calculated by the formula b = 1/13d + 0.3, where d is the bore diameter. For spherical extrusion heads, the ball diameter is typically D = d + interference allowance.
2. Interference Allowance
The difference between the diameter of the extrusion head and the original bore diameter is called the interference allowance. If the interference is too small, the bore surface cannot be fully smoothed. If it is too large, it may cause surface tearing or scratching. The appropriate allowance depends on the workpiece material, bore diameter, and wall thickness, and it is generally controlled within 0.05–0.1 mm. For smaller bores or thinner wall sections, a smaller value is recommended.
3. Extrusion Methods
When the bore is relatively short and the diameter is large, push extrusion is commonly used. For longer bores or smaller diameters, pull extrusion is generally more suitable. Pull extrusion can also be carried out on a broaching machine or other suitable pulling equipment.
4. Extrusion Speed
For plastic materials, the recommended cutting speed is generally Vc = 2–5 m/min. For brittle materials, such as cast iron or brass, the recommended speed is Vc = 5–7 m/min. Selecting the correct speed helps achieve better surface quality and reduces the risk of defects during processing.
5. Lubricants for Extrusion
Lubrication plays an important role in deep hole extrusion. For plastic materials, suitable lubricants include grease, MoS₂ paste, or mechanical oil mixed with graphite. For brittle materials, a mixture of mechanical oil and soybean oil is often used. When processing aluminum, a high-concentration emulsion is recommended, while for cast iron, kerosene is commonly applied. Among these options, mechanical oil mixed with graphite often delivers the best overall performance.
Extrusion processing is a method for surface finishing and strengthening small-diameter bores. It is capable of achieving an accuracy grade of IT5–IT6 and a surface roughness of Ra 1.6–0.21 μm; furthermore, it requires only simple tooling and places minimal demands on the precision of the machine tool. This process is suitable for bores with diameters ranging from Φ2 mm to Φ50 mm and offers high machining efficiency. Its key characteristics include dimensional refinement, surface burnishing, and surface layer strengthening.
Compared to traditional processes that rely solely on cutting operations, this type of finishing process offers the following advantages:
Reduces surface roughness
Enhances wear resistance
Increases the fatigue strength of the surface layer
Improves sealing reliability
Extends the service life of pressure-bearing systems
Professional experience in precision steel tube manufacturing Focus on hydraulic cylinder tube applications Attention to inner bore quality and surface finish Flexible production for custom dimensions Stable quality control from raw material to final inspection Export-oriented service for international customers Fast response for technical and commercial inquiries
At Changzhou Fengdie Metal Technology Co., Ltd, we are committed to helping customers source the right precision steel tube deep hole honing and extrusion solution for their business.
Quality Control for Better Tube Performance
Reliable tube performance starts with reliable manufacturing control. We understand that for industrial buyers, consistency is as important as the sample itself.
Our production and inspection focus includes:
Raw material selection
Dimension control
Inner bore quality inspection
Surface finish evaluation
Straightness verification
Final packaging protection for export
Customization Service
Different customers have different project requirements. That is why we support customized production based on your drawings, specifications, and application needs.
Custom options may include:
Outer diameter
Inner diameter
Tube length
Tolerance range
Surface finish requirement
Material grade
Application-specific processing
1.What is the advantage of deep hole honing in precision steel tubes?
Deep hole honing improves internal bore accuracy, straightness, roundness, and surface finish, making the tube more suitable for hydraulic sealing and precision mechanical applications.
2.Are honed tubes suitable for hydraulic cylinders?
Yes. Honed tubes are widely used in hydraulic cylinders because they provide a smoother and more accurate internal surface, which helps reduce friction and improve seal life.
3.Can Changzhou Fengdie Metal Technology Co., Ltd provide customized precision steel tubes?
Yes. We can support customized dimensions, lengths, and processing requirements based on customer needs.
4.What industries use precision steel tubes with honing and extrusion processing?
These tubes are commonly used in hydraulic systems, engineering machinery, automation equipment, construction machinery, mining equipment, and other industrial applications.
