Carbon Seamless Steel Pipe Specification Chart

As the basic material in the industrial field, the specification parameters of carbon seamless steel pipe directly affect the engineering selection and performance. The following systematically sorts out the specification and technical points of carbon seamless steel pipe from the aspects of standard system, specification analysis, material performance and application scenarios.

Standard system and classification

The three major standard systems mainly implemented in the world are ASTM (American standard), DIN (German standard) and GB/T (national standard). The national standard GB/T 8163-2018 divides carbon steel seamless pipes into:

Structural pipes (such as 20#, 45# steel): outer diameter 6-630mm, wall thickness 1-50mm

Fluid transport pipes (such as Q345B): outer diameter 10-1220mm, wall thickness 1.5-120mm

High-pressure boiler tubes (such as 20G): need to pass -40℃ low-temperature impact test

American standard ASTM A106 is divided into three grades A/B/C, and the tensile strength is required to be ≥330/415/485MPa respectively.

The German standard DIN 2448 focuses on precision machinery pipes, and the tolerance is controlled within ±0.3mm.

Analysis of the specifications of carbon steel seamless pipes

Carbon steel seamless pipes are a kind of pipes with high strength, toughness and plasticity, which are widely used in petroleum, chemical, aviation, machinery and other fields. The specifications of carbon steel seamless pipes generally include outer diameter, wall thickness, length and material.

1. Outer diameter

The outer diameter of carbon seamless steel pipe generally ranges from 6mm to 1020mm, and the commonly used outer diameters are 57mm and 76mm. The larger the outer diameter, the thicker the pipe wall and the stronger the load-bearing capacity.

Small diameter: 6/10/13/17/21/27 (for precision instruments)

Conventional diameter: 32/38/42/48/57 (mainstream of hydraulic piping system)

Large diameter: ≥159mm (oil and gas trunk pipeline)

2. Wall thickness

The wall thickness of carbon seamless steel pipe generally ranges from 1mm to 100mm, and the commonly used wall thicknesses are 5mm and 6mm. The thicker the wall, the stronger the load-bearing capacity of the pipe.

Series number: Sch5 to Sch160, such as Sch40 means pressure bearing 4MPa

Wall thickness formula: δ=(P×D)/(2σφ+P) (P pressure, D diameter, σ allowable stress, φ weld coefficient)

3. Length

The length of carbon seamless steel pipe generally ranges from 6 meters to 12 meters, and the length can be customized according to needs.

4. Material

The material of carbon seamless steel pipe is generally 20#, 45# and Q345, etc. Different materials are selected according to different application scenarios.

Fixed length: 6m/9m/12m (commonly used in building structures)

Multiple length: 1.5m (maximum 18m)

Rolled pipe: outer diameter ≤114mm can be delivered in rolls

Carbon steel seamless pipe specification list

The following table lists the commonly used carbon steel seamless pipe specifications:

Material mechanical properties comparison

Special working conditions need to be noted:

Low temperature environment: L245NB and other cold-resistant steel grades should be selected below -46℃

Corrosive environment: ST45.8 galvanized pipe (zinc layer ≥80μm) is recommended

Typical application scenario specification matching

1. Engineering machinery hydraulic system

Excavator main oil pipe: Φ42×5mm 27SiMn steel

Crane outrigger: Φ168×14mm Q460C

2. Energy transportation field

Shale gas gathering and transportation pipeline: Φ323.9×7.1mm L360N

Heat network: Φ630×8mm 20# steel + polyurethane insulation layer

3. Special equipment manufacturing

Pressure vessel shell: Φ1020×16mm Q345R

Marine boiler tube: Φ38×3.5mm 20G

Read more: Roughness of carbon steel pipe or Thermal conductivity of carbon steel pipe