Cold drawn seamless tubes, also known as cold-drawn precision seamless steel tubes, are a type of high-precision steel tube. Compared to commonly used hot-rolled seamless tubes, they differ significantly in both manufacturing processes and final product characteristics.
What is Cold Drawn Seamless Tube?
Cold-drawn seamless tubing is produced using seamless steel tube blanks or finished products as raw materials. At room temperature, the material is drawn through the dies of a cold drawing machine to form the desired shape without heating. The final product features smaller dimensions, thinner walls, and increased length. The core processes include cutting, piercing, rolling, acid washing, and cold drawing. Some products may also require annealing to eliminate internal stresses. Using precision seamless tubes for the manufacture of mechanical structures or hydraulic equipment can significantly reduce machining time, improve material utilization, and enhance product quality.
Advantages of Cold Drawn Seamless Tubes
High Precision: The cold drawing process strictly controls the dimensional tolerances of the tube, including outer diameter and wall thickness.
Surface Quality: After cold drawing, the tube’s inner and outer surfaces are smooth, free of oxide layers, and exhibit excellent surface quality.
Mechanical Properties: The cold drawing process plastically deforms the steel, thereby increasing its hardness, tensile strength, and other mechanical properties.
Diverse dimensions: It enables the production of small-diameter, thin-walled tubes that are difficult to manufacture using hot-rolled processes.
Manufacturing Process
Tube blank preparation: Select suitable steel materials, such as low-carbon steel, medium-carbon steel, or alloy steel, as raw materials. Heat the steel blank to 1100°C–1300°C to facilitate subsequent piercing and drawing processes.
Piercing: The heated steel billet is fed into the piercing machine, where it is drawn through the machine’s internal drawing equipment to form a hollow tube shape. The pierced billet is then water-cooled.
Cold drawing: The hollow steel tube after piercing is sent into the cold drawing machine, where it is drawn through a die at room temperature or near room temperature to achieve the desired dimensions and shape. Common cold drawing methods include single-pass cold drawing and multi-pass cold drawing.
Heat treatment: To enhance the mechanical properties of the steel tube, such as hardness, strength, and toughness, heat treatment processes such as annealing, normalizing, quenching, and tempering are typically performed.
Acid washing: After heat treatment, the surface of the steel tube typically forms scale and other impurities. These are removed by immersing the steel tube in an acid solution to remove the oxide layer and impurities from the surface.
Anti-Rust Oiling: The steel pipe surface is coated with anti-rust oil to prevent rust.
Inspection and Testing: The steel pipe undergoes mechanical property tests such as tensile testing, hardness testing, and bending testing. The outer diameter, inner diameter, and wall thickness are measured, and surface and internal defects are inspected to ensure that the steel pipe meets quality standards.
Packaging and Shipping: The steel pipe is packaged and shipped in bundles, plastic packaging, or wooden crates.
Materials of Cold Drawn Seamless Tubes
| Material Category | GB Grade (China) | ASTM/ASME Grade (USA) | Main Features |
| Carbon Steel | 20# | ASTM A106 Gr.B / ASTM A53 Gr.B | For medium and low-pressure delivery, mechanical structures |
| Alloy Steel | 15CrMo | ASTM A335 P12 | High temperature and high pressure resistance, used in boilers and petrochemical industry |
| 12CrMo | ASTM A335 P1 | For high temperature steam and heat exchanger tubes | |
| 12Cr1MoV | ASTM A335 P11 | High temperature strength, good creep resistance | |
| Stainless Steel | 304 | ASTM A312 TP304 | Corrosion and heat resistant, commonly used in food and chemical industries |
| 304L | ASTM A312 TP304L | Low carbon, excellent intergranular corrosion resistance | |
| 316 | ASTM A312 TP316 | Excellent chloride corrosion resistance | |
| 316L | ASTM A312 TP316L | Low carbon, suitable for welding environments | |
| 321 | ASTM A312 TP321 | Titanium-stabilized, resists high-temperature intergranular corrosion |
Surface Quality
The inner and outer surfaces of steel tubes should be smooth. The depth of local pits, scratches, and fine scratches should not exceed 0.08 mm. At these defective locations, the actual wall thickness of the steel
Tube should not be less than the minimum value allowed by the wall thickness deviation.
Defects on the inner and outer surfaces of steel tubes may be removed using appropriate methods. The actual wall thickness at the cleaned areas shall not be less than the minimum value allowed by the wall thickness deviation.
Steel pipes delivered in a cold-worked state may have residual phosphates produced during the manufacturing process on their surfaces. Steel pipes delivered in a heat-treated state may have an oxide film on their inner and outer surfaces that does not affect surface inspection.
Cold Drawn Seamless Tube Specification Table
| Φ4×0.5 | Φ16×0.5 | Φ26×1.8 | Φ35×9.0 | Φ48×5.0 | Φ70×2.8 |
| Φ4×0.8 | Φ16×0.8 | Φ26×2.0 | Φ35×10 | Φ48×5.5 | Φ70×3.0 |
| Φ4×1.0 | Φ16×1.0 | Φ26×2.2 | Φ38×0.5 | Φ48×6.0 | Φ70×3.5 |
| Φ4×1.2 | Φ16×1.2 | Φ26×2.5 | Φ38×0.8 | Φ48×7.0 | Φ70×4.0 |
| Φ5×0.5 | Φ16×1.5 | Φ26×2.8 | Φ38×1.0 | Φ48×8.0 | Φ70×4.5 |
| Φ5×0.8 | Φ16×1.8 | Φ26×3.0 | Φ38×1.2 | Φ48×9.0 | Φ70×5.0 |
| Φ5×1.0 | Φ16×2.0 | Φ26×3.5 | Φ38×1.5 | Φ48×10 | Φ70×5.5 |
| Φ5×1.2 | Φ16×2.2 | Φ26×4.0 | Φ38×1.8 | Φ50×1.0 | Φ70×6.0 |
| Φ6×0.5 | Φ16×2.5 | Φ26×4.5 | Φ38×2.0 | Φ50×1.2 | Φ70×7.0 |
| Φ6×0.8 | Φ16×2.8 | Φ26×5.0 | Φ38×2.2 | Φ50×1.5 | Φ70×8.0 |
| Φ6×1.0 | Φ16×3.0 | Φ26×5.5 | Φ38×2.5 | Φ50×1.8 | Φ70×9.0 |
| Φ6×1.2 | Φ16×3.5 | Φ26×6.0 | Φ38×2.8 | Φ50×2.0 | Φ70×10 |
| Φ6×1.5 | Φ16×4.0 | Φ26×7.0 | Φ38×3.0 | Φ50×2.2 | Φ70×12 |
| Φ6×1.8 | Φ16×4.5 | Φ26×8.0 | Φ38×3.5 | Φ50×2.5 | Φ70×14 |
| Φ6×2.0 | Φ16×5.0 | Φ28×0.5 | Φ38×4.0 | Φ50×2.8 | Φ75×1.0 |
| Φ7×0.5 | Φ16×5.5 | Φ28×0.8 | Φ38×4.5 | Φ50×3.0 | Φ75×1.2 |
| Φ7×0.8 | Φ16×6.0 | Φ28×1.0 | Φ38×5.0 | Φ50×3.5 | Φ75×1.5 |
| Φ7×1.0 | Φ18×0.5 | Φ28×1.2 | Φ38×5.5 | Φ50×4.0 | Φ75×1.8 |
| Φ7×1.2 | Φ18×0.8 | Φ28×1.5 | Φ38×6.0 | Φ50×4.5 | Φ75×2.0 |
| Φ7×1.5 | Φ18×1.0 | Φ28×1.8 | Φ38×7.0 | Φ50×5.0 | Φ75×2.2 |
| Φ7×1.8 | Φ18×1.2 | Φ28×2.0 | Φ38×8.0 | Φ50×5.5 | Φ75×2.5 |
| Φ7×2.0 | Φ18×1.5 | Φ28×2.2 | Φ38×9.0 | Φ50×6.0 | Φ75×2.8 |
| Φ8×0.5 | Φ18×1.8 | Φ28×2.5 | Φ38×10 | Φ50×7.0 | Φ75×3.0 |
| Φ8×0.8 | Φ18×2.0 | Φ28×2.8 | Φ40×0.5 | Φ50×8.0 | Φ75×3.5 |
| Φ8×1.0 | Φ18×2.2 | Φ28×3.0 | Φ40×0.8 | Φ50×9.0 | Φ75×4.0 |
| Φ8×1.2 | Φ18×2.5 | Φ28×3.5 | Φ40×1.0 | Φ50×10 | Φ75×4.5 |
| Φ8×1.5 | Φ18×2.8 | Φ28×4.0 | Φ40×1.2 | Φ55×1.0 | Φ75×5.0 |
| Φ8×1.8 | Φ18×3.0 | Φ28×4.5 | Φ40×1.5 | Φ55×1.2 | Φ75×5.5 |
| Φ8×2.0 | Φ18×3.5 | Φ28×5.0 | Φ40×1.8 | Φ55×1.5 | Φ75×6.0 |
| Φ8×2.2 | Φ18×4.0 | Φ28×5.5 | Φ40×2.0 | Φ55×1.8 | Φ75×7.0 |
| Φ8×2.5 | Φ18×4.5 | Φ28×6.0 | Φ40×2.2 | Φ55×2.0 | Φ75×8.0 |
| Φ9×0.5 | Φ18×5.0 | Φ28×7.0 | Φ40×2.5 | Φ55×2.2 | Φ75×9.0 |
| Φ9×0.8 | Φ18×5.5 | Φ28×8.0 | Φ40×2.8 | Φ55×2.5 | Φ75×10 |
| Φ9×1.0 | Φ18×6.0 | Φ30×0.5 | Φ40×3.0 | Φ55×2.8 | Φ75×12 |
| Φ9×1.2 | Φ20×0.5 | Φ30×0.8 | Φ40×3.5 | Φ55×3.0 | Φ75×14 |
| Φ9×1.5 | Φ20×0.8 | Φ30×1.0 | Φ40×4.0 | Φ55×3.5 | Φ75×16 |
| Φ9×1.8 | Φ20×1.0 | Φ30×1.2 | Φ40×4.5 | Φ55×4.0 | Φ80×1.0 |
| Φ9×2.0 | Φ20×1.2 | Φ30×1.5 | Φ40×5.0 | Φ55×4.5 | Φ80×1.2 |
| Φ9×2.2 | Φ20×1.5 | Φ30×1.8 | Φ40×5.5 | Φ55×5.0 | Φ80×1.5 |
Cold Drawn Seamless Tube Specification Table
| Φ10×1.8 | Φ20×4.0 | Φ30×4.5 | Φ42×1.5 | Φ60×1.0 | Φ80×4.0 |
| Φ10×2.0 | Φ20×4.5 | Φ30×5.0 | Φ42×1.8 | Φ60×1.2 | Φ80×4.5 |
| Φ10×2.2 | Φ20×5.0 | Φ30×5.5 | Φ42×2.0 | Φ60×1.5 | Φ80×5.0 |
| Φ10×2.5 | Φ20×5.5 | Φ30×6.0 | Φ42×2.2 | Φ60×1.8 | Φ80×5.5 |
| Φ10×2.8 | Φ20×6.0 | Φ30×7.0 | Φ42×2.5 | Φ60×2.0 | Φ80×6.0 |
| Φ10×3.0 | Φ20×7.0 | Φ30×8.0 | Φ42×2.8 | Φ60×2.2 | Φ80×7.0 |
| Φ12×0.5 | Φ22×0.5 | Φ30×9.0 | Φ42×3.0 | Φ60×2.5 | Φ80×8.0 |
| Φ12×0.8 | Φ22×0.8 | Φ30×10 | Φ42×3.5 | Φ60×2.8 | Φ80×9.0 |
| Φ12×1.0 | Φ22×1.0 | Φ32×0.5 | Φ42×4.0 | Φ60×3.0 | Φ80×10 |
| Φ12×1.2 | Φ22×1.2 | Φ32×0.8 | Φ42×4.5 | Φ60×3.5 | Φ80×12 |
| Φ12×1.5 | Φ22×1.5 | Φ32×1.0 | Φ42×5.0 | Φ60×4.0 | Φ80×14 |
| Φ12×1.8 | Φ22×1.8 | Φ32×1.2 | Φ42×5.5 | Φ60×4.5 | Φ80×16 |
| Φ12×2.0 | Φ22×2.0 | Φ32×1.5 | Φ42×6.0 | Φ60×5.0 | Φ85×1.5 |
| Φ12×2.2 | Φ22×2.2 | Φ32×1.8 | Φ42×7.0 | Φ60×5.5 | Φ85×1.8 |
| Φ12×2.5 | Φ22×2.5 | Φ32×2.0 | Φ42×8.0 | Φ60×6.0 | Φ85×2.0 |
| Φ12×2.8 | Φ22×2.8 | Φ32×2.2 | Φ42×9.0 | Φ60×7.0 | Φ85×2.2 |
| Φ12×3.0 | Φ22×3.0 | Φ32×2.5 | Φ42×10 | Φ60×8.0 | Φ85×2.5 |
| Φ12×3.5 | Φ22×3.5 | Φ32×2.8 | Φ45×1.0 | Φ60×9.0 | Φ85×2.8 |
| Φ12×4.0 | Φ22×4.0 | Φ32×3.0 | Φ45×1.2 | Φ60×10 | Φ85×3.0 |
| Φ14×0.5 | Φ22×4.5 | Φ32×3.5 | Φ45×1.5 | Φ60×12 | Φ85×3.5 |
| Φ14×0.8 | Φ22×5.0 | Φ32×4.0 | Φ45×1.8 | Φ65×1.0 | Φ85×4.0 |
| Φ14×1.0 | Φ22×5.5 | Φ32×4.5 | Φ45×2.0 | Φ65×1.2 | Φ85×4.5 |
| Φ14×1.2 | Φ22×6.0 | Φ32×5.0 | Φ45×2.2 | Φ65×1.5 | Φ85×5.0 |
| Φ14×1.5 | Φ22×7.0 | Φ32×5.5 | Φ45×2.5 | Φ65×1.8 | Φ85×5.5 |
| Φ14×1.8 | Φ25×0.5 | Φ32×6.0 | Φ45×2.8 | Φ65×2.0 | Φ85×6.0 |
| Φ14×2.0 | Φ25×0.8 | Φ32×7.0 | Φ45×3.0 | Φ65×2.2 | Φ85×7.0 |
| Φ14×2.2 | Φ25×1.0 | Φ32×8.0 | Φ45×3.5 | Φ65×2.5 | Φ85×8.0 |
| Φ14×2.5 | Φ25×1.2 | Φ32×9.0 | Φ45×4.0 | Φ65×2.8 | Φ85×9.0 |
| Φ14×2.8 | Φ25×1.5 | Φ32×10 | Φ45×4.5 | Φ65×3.0 | Φ85×10 |
| Φ14×3.0 | Φ25×1.8 | Φ35×0.5 | Φ45×5.0 | Φ65×3.5 | Φ85×12 |
| Φ14×3.5 | Φ25×2.0 | Φ35×0.8 | Φ45×5.5 | Φ65×4.0 | Φ85×14 |
| Φ14×4.0 | Φ25×2.2 | Φ35×1.0 | Φ45×6.0 | Φ65×4.5 | Φ85×16 |
| Φ14×4.5 | Φ25×2.5 | Φ35×1.2 | Φ45×7.0 | Φ65×5.0 | Φ90×1.5 |
| Φ15×0.5 | Φ25×2.8 | Φ35×1.5 | Φ45×8.0 | Φ65×5.5 | Φ90×1.8 |
| Φ15×0.8 | Φ25×3.0 | Φ35×1.8 | Φ45×9.0 | Φ65×6.0 | Φ90×2.0 |
| Φ15×1.0 | Φ25×3.5 | Φ35×2.0 | Φ45×10 | Φ65×7.0 | Φ90×2.2 |
| Φ15×1.2 | Φ25×4.0 | Φ35×2.2 | Φ48×1.0 | Φ65×8.0 | Φ90×2.5 |
| Φ15×1.5 | Φ25×4.5 | Φ35×2.5 | Φ48×1.2 | Φ65×9.0 | Φ90×2.8 |
| Φ15×1.8 | Φ25×5.0 | Φ35×2.8 | Φ48×1.5 | Φ65×10 | Φ90×3.0 |
Difference Between Hot Rolled and Cold Drawn Seamless Tubes?
· Process comparison:
Cold drawing: processed at room temperature, high dimensional accuracy, but low production efficiency.
Hot-rolled: High-temperature rolling, high production efficiency, but with oxide scale on the surface and lower precision.
· Appearance and Performance:
Cold-drawn tubes have a smooth surface and high gloss, while hot-rolled tubes have a rough surface and may have a decarburized layer.
The wall thickness deviation of cold-drawn tubes is reduced by 40% compared to hot-rolled tubes, and they have lower surface roughness.
Application Areas
Machinery Manufacturing: Used in the production of various mechanical components, such as hydraulic cylinder piston rods, pneumatic cylinder piston rods, and precision shafts. Its high precision and excellent mechanical properties ensure the assembly accuracy and operational reliability of components.
Automotive Manufacturing: Cold drawn seamless tubes are often used in automotive parts to meet the industry’s demand for high strength, high precision and lightweight design.
Aerospace: Used for manufacturing aircraft hydraulic system tubes, engine fuel supply tubes, etc. Its high quality and performance ensure the safe and reliable operation of aerospace equipment.
Medical Devices: Some medical devices, also use cold-drawn seamless tubes, which require extremely high precision, surface quality, and hygiene performance.
Other Fields: They are also widely used in industries such as electronics, instruments, and architectural decoration. Such as heat sink tubes in electronic devices and stainless steel handrails in architectural decoration.
ZIZI offer both hot-rolled and cold-drawn tubes in a variety of materials, including carbon steel, alloy steel, and stainless steel. Equipped with advanced production lines and comprehensive testing equipment, we can customize steel tubes in various specifications, materials, and lengths to meet customer needs. We provide one-stop services including cutting, beveling, heat treatment, and surface treatment, ensuring that every product meets customer standards.