ERW Pipe OD and Wall Thickness Chart and Specifications

　　ERW pipes are widely used in construction, oil & gas, water transmission, and structural applications. One of the most critical factors when selecting ERW pipes is understanding outer diameter (OD) and wall thickness, as these directly affect pressure capacity, strength, weight, and compliance with international standards.

　　Shengtian Group provides a comprehensive overview of ERW pipe OD and wall thickness, including standards, size ranges, schedules, and selection tips.

　　ERW Pipe Outer Diameter and Wall Thickness Specifications Table

　　The following is a table showing common outer diameter and wall thickness specifications for ERW pipes, compiled based on standards such as API 5L and GB/T 3091.  It should be noted that actual specifications may vary slightly depending on the manufacturer, steel grade, and standard system used. For specific applications, the product standard or purchase contract should be consulted.

　　Table 1: Small Diameter ERW Pipe Outer Diameter and Wall Thickness Specifications (Outer Diameter ≤ 114mm)

　　Table 2: Specifications of Medium and Large Diameter ERW Pipes (Outer Diameter 114-508mm)

　　The wall thickness values above are for common specifications; non-standard wall thicknesses can be customized according to requirements during actual production. For large-diameter ERW pipes (outer diameter > 508mm), LSAW (longitudinal submerged arc welding) is often used, while the ERW process mainly covers small and medium-diameter ranges.

　　Specifications System Description

　　1. Relationship between Nominal Diameter and Outer Diameter

　　The nominal diameter of ERW pipes is usually expressed in inches, but the actual outer diameter is measured in millimeters. This "inch-based naming, metric dimensions" system stems from the common practice of international standards (such as API standards). For example, an ERW pipe with a nominal diameter of 6 inches has an actual outer diameter of 168.3 mm, not 152.4 mm (6 × 25.4), because the standard takes into account factors such as pipe end processing and fitting connections.

　　2. Wall Thickness Series

　　The wall thickness of ERW pipes is usually divided into the following series:

　　SCH series: such as SCH40, SCH80, SCH160, etc., where a larger number indicates a thicker wall and stronger pressure bearing capacity.

　　Standard Wall Thickness (STD): Regular pressure rating

　　Extra Heavy Wall Thickness (XS/XH): Used for high pressure or special working conditions

　　Non-standard Wall Thickness: Customized according to engineering requirements

　　For different nominal diameters, the actual wall thickness corresponding to the same SCH number is different. For example, the wall thickness of SCH40 is 3.91 mm in a 2-inch pipe and 8.18 mm in an 8-inch pipe.

　　3. Steel Grade and Wall Thickness Limitations

　　The selection of ERW pipe wall thickness needs to consider the steel grade (material strength):

　　Low steel grades (such as Q235, L245): Wider wall thickness range, up to 25 mm or more

　　High steel grades (such as X70, X80): Due to welding process limitations, the maximum wall thickness usually does not exceed 16 mm (small diameter) or 22 mm (large diameter)

　　Special steel grades: Such as low-temperature steel, corrosion-resistant steel, etc., the wall thickness specifications need to be determined according to specific standards.

　　ERW Pipe Standards and Size Tolerances

　　Different standards define OD and wall thickness tolerances:

　　ASTM A53 / A500-Used for structural and pressure applications

　　API 5L ERW Pipe-Common in oil and gas pipelines (Grades B, X42–X70)

　　EN 10219 / EN 10217-European standards for structural and pressure pipes

　　Typical tolerances:

　　OD: ±0.5% to ±1.0%

　　Wall thickness: ±10% (depending on standard)

　　The outer diameter and wall thickness specifications of ERW pipes are fundamental for engineering design and selection. In practical applications, these specifications should be determined comprehensively considering factors such as the conveyed medium, working pressure, environmental conditions, and economic feasibility. For specific projects, relevant standards and specifications should be followed, and customized solutions can be obtained from manufacturers Email : pipe@stpipefitting.cn.