Cold drawn seamless steel pipe size chart

Cold drawn seamless steel pipes are widely used in applications where high dimensional accuracy, smooth surface finish, and tight tolerances are required. Compared with hot rolled pipes, cold drawn tubes offer better precision and consistency, making them ideal for hydraulic systems, automotive parts, and precision engineering.

This guide provides an overview of size ranges, application categories, selection principles, and standards of cold drawn seamless steel pipe.

Quick Answer

Outer Diameter (OD): 5 mm – 200 mm

Wall Thickness (WT): 0.5 mm – 20 mm

Most Common Range:

OD: 10 – 120 mm

WT: 0.5 – 12 mm

Cold drawn pipes are preferred when tight tolerances and superior surface quality are critical.

1. Cold Drawn Seamless Steel Pipe Size Classification

To simplify engineering selection, cold drawn seamless pipes are typically grouped by outer diameter:

1.1 Small Precision Tubes (OD 5–50 mm)

Applications:

Instrumentation tubing

Automotive components

Precision machinery

Hydraulic and pneumatic systems

Typical Size Range:

OD: 5 – 50 mm

WT: 0.5 – 5.0 mm

Key Features:

Extremely tight tolerances

Uniform wall thickness

Thin-wall tubes (<2 mm) are almost exclusively cold drawn

Typical Tolerance:

OD: ±0.05 mm

WT: ±5%
(Compliant with GB/T 3639 / DIN 2391)

1.2 Medium Precision Tubes (OD 50–120 mm)

This is the mainstream application range for cold drawn pipes.

Applications:

Hydraulic cylinders

Construction machinery

Industrial lifting systems

Typical Size Range:

OD: 50 – 120 mm

WT: 2.0 – 12.0 mm

Key Features:

Mature production process

Stable supply and cost

Widely used in engineering projects

Typical Tolerance:

OD: ±0.08 mm

WT: ±5%–8%

1.3 Large Diameter Tubes (OD 120–200 mm)

Applications:

Heavy-duty hydraulic cylinders

Mining equipment

Tunnel boring machines (TBM)

Large industrial systems

Typical Size Range:

OD: 120 – 200 mm

WT: 5.0 – 20.0 mm

Important Notes:

Production depends on manufacturer capability

Longer lead time and higher cost (≈30%–50% more)

For loose tolerance requirements, hot rolled + honing may be more economical

2. Representative Size Chart of Cold Drawn Seamless Steel Pipe

Note: Detailed combinations depend on standards and supplier capabilities.

3. How to Choose the Right Size

3.1 Start with Outer Diameter (OD)

≤ 50 mm → Precision small tubes

50–120 mm → Optimal engineering range

> 120 mm → Confirm production feasibility

3.2 Match Wall Thickness (WT) to Pressure

Typical engineering guidance:

WT 2–3 mm → Low pressure / structural use

WT 3–5 mm → Standard hydraulic systems

WT ≥ 6 mm → High-pressure applications

Note: Final design should comply with ASME B31.3 or GB/T 20801.

3.3 Consider Tolerance Grade

IT10–IT11 → General applications

IT8–IT9 → Precision systems (hydraulic cylinders, machining parts)

Higher precision increases cost but reduces machining allowance and rejection rates.

4. Wall Thickness vs Pressure of Cold Drawn Seamless Steel Pipe

Example (OD ≈ 50 mm, carbon steel):

WT 2.0 mm → ~12–16 MPa

WT 3.0 mm → ~20–25 MPa

WT 4.0 mm → ~28–35 MPa

WT 5.0 mm → ~35–42 MPa

WT ≥ 6.0 mm → ≥45 MPa

For reference only. Always verify with design codes.

5. Common Standards and Delivery Conditions of Cold Drawn Seamless Steel Pipe

Main Standards

GB/T 3639 → Precision cold drawn tubes

DIN 2391 → European precision standard

ASTM A179 → Heat exchanger tubes (mandatory cold drawn)

ASTM A106 → High-temperature pipes (cold drawn allowed with compliance)

EN 10216-1 → Pressure applications

Delivery Conditions

BK (Cold Drawn) → High strength, high residual stress

BKS (Stress-relieved) → Improved stability

GBK (Annealed) → High ductility

NBK (Normalized) → Balanced mechanical properties

FAQ

Q1: What is a cold drawn seamless steel pipe?

It is a seamless steel pipe processed by cold drawing, resulting in higher precision and better surface finish than hot rolled pipes.

Q2: What is the most common size range?

The most widely used range is OD 10–120 mm and WT 0.5–12 mm.

Q3: Why choose cold drawn over hot rolled pipes?

Cold drawn pipes provide tighter tolerances, smoother surfaces, and better dimensional control.

Q4: Are large diameter cold drawn pipes common?

No, pipes above 120 mm OD are less common and depend on manufacturing capability.

Q5: How do I select the right pipe size?

Follow this workflow:

Confirm OD range

Select WT based on pressure

Choose tolerance grade

Verify standards and processing requirements

Conclusion

Cold drawn seamless steel pipes are essential for applications requiring precision, consistency, and high performance. While size charts provide a reference, real-world selection must consider OD, wall thickness, tolerance, pressure, and manufacturing feasibility.

For critical projects, always verify specifications against relevant standards and supplier capabilities to ensure optimal results.