Carbon steel pipe diameters

Carbon steel pipes have a wide range of diameters to meet different industrial needs. Below is a detailed breakdown of common diameter specifications based on manufacturing methods, standards, and applications:

Diameter range classified by manufacturing process

1. Seamless Pipe
Standard diameter:

Small caliber: 1/8 inch (about 10.3 mm) to 8 inch (219.1 mm), suitable for high-pressure fluid delivery (such as boiler tubes, hydraulic systems).
Medium diameter: 8 inches (219.1 mm) to 30 inches (762 mm), used in petroleum refining and chemical equipment.

Special specifications:

Ultra-thick wall tubes: up to 26 inches (660 mm) in diameter and up to 100 mm in wall thickness are used in extreme high-pressure environments such as deep sea drilling.

Standard reference:

API 5CT (casing) : 1.9 inches (48.3 mm) to 20 inches (508 mm).
ASTM A106/A53:1/8 "to 30" for high temperature fluid delivery.

2. Welded carbon steel Pipe
ERW (Resistance Welded Pipe) :

Diameter range: 1/2 inch (21.3 mm) to 24 inches (610 mm), commonly found in low-pressure water and gas networks, building structures.

Typical standards: ASTM A53, API 5L Gr.B.

LSAW (Straight seam submerged arc welded pipe) :

Diameter range: 8 inches (219.1 mm) to 72 inches (1,820 mm) for long distance oil/gas lines.

SSAW (Spiral submerged Arc Welded Pipe) :

Diameter range: 8 inches (219.1 mm) to 100 inches (2,540 mm), suitable for large diameter low-pressure transport (such as municipal drainage).

 Typical diameters classified by application scenario
1. Oil and gas industry
Well casing (API 5CT) :

Common diameters: 4.5 in (114.3 mm), 7 in (177.8 mm), 9.625 in (244.5 mm) for different well depths and pressure levels.

Pipeline (API 5L) :

Standard diameters: 2 inches (50.8 mm) to 48 inches (1,219 mm), such as 24 inches (610 mm) for X70 class pipelines.

2. Architectural and Structural engineering
Structural tubes (ASTM A500/A53) :

Common diameters: 1/2 inch (21.3 mm) to 24 inches (610 mm), used for Bridges, scaffolding, etc.

Piling pipe:

Large diameter: 24 inches (610 mm) to 60 inches (1,524 mm), wall thickness up to 40 mm.

Machinery and automobile manufacturing
Precision mechanical tube:

Small diameter: 8 mm (0.315 in) to 150 mm (5.9 in) for hydraulic cylinders and drive shafts.

Exhaust pipe:

Medium diameter: 2 inches (50.8 mm) to 6 inches (152.4 mm), made of heat-resistant carbon steel (e.g. ASTM A179).

Common tube list number:

SCH 10: Thin-walled for low pressure (such as SCH 10S stainless steel pipe).
SCH40: Standard wall thickness, universal type (e.g. DN50 SCH40 outer diameter 60.3mm, wall thickness 3.91mm).
SCH 80/XXH: Ultra-thick wall for high pressure or corrosive environments.

Calculation formula

Wall thickness (mm) = outer diameter (mm) × Schedule value / 1000, for example: SCH40 tube with outer diameter 114.3mm, wall thickness ≈4.5mm.