ERW Pipe Specifications and Models

ERW piping specifications and models are an essential part of many industrial systems and processes. They are made of steel and are critical components in the transport of fluids and gases. ERW pipe comes in a variety of sizes, shapes and materials, each with its own set of technical specifications. Knowing these specifications is critical to choosing the right pipe for the right job.

Types of ERW pipes

ERW pipe comes in many shapes and sizes. The most common type is round pipe, which is often used to transport liquids and gases in residential and commercial applications. Square and rectangular ducts are used in architectural applications as well as furniture and decorations. Special shaped tubing such as U-bends and can also be produced by ERW Tube Fabrication. ERW pipes are versatile and come in a variety of different sizes, shapes, models and specifications.

First, it is important to understand the basic types of ERW pipes available in the market today. ERW pipe is generally classified by its two main categories, including: straight welded pipe and spiral welded pipe.

 

1. Straight Seam Electric Resistance Welded Pipe

Straight welded pipe is made by passing a continuous strip of steel through sets of rollers that bend, shape and flatten the strip before forming a welded joint along its length. This process creates a seamless, leak-proof pipe with excellent mechanical properties.

Features: Uniform weld seam, smooth inner and outer surfaces, and consistent wall thickness.

Typical Applications: Structural steel pipe, water pipe, oil and gas pipeline, and automotive manufacturing.

 

2. Spiral Electric Resistance Welded Pipe

Spiral welded pipe, is made by rolling flat metal strip into a tube shape and welding the edges together. This process produces stronger, more reliable pipe with a higher pressure rating.

Features: Can produce larger diameter pipes (>600mm) with improved pressure resistance.

Typical Applications: Large-scale oil and gas transmission projects, submarine pipelines, and steel structure supports.

Material Specification

ERW pipe is typically made from mild steel grades A53 to A106. The most commonly used grade is A53B, which has a minimum yield strength of 30,000 psi. Other materials, such as stainless steel, copper, and aluminum, can also be used to manufacture ERW pipe, depending on application requirements.

Standard	Common Material	Minimum Yield Strength
ASTM A53 Grade B	Carbon Steel	≥ 240 MPa
ASTM A252 Grade 2 / 3	Carbon Steel	≥ 310 MPa
API 5L Grade B / X42 / X52	Pipeline Steel	≥ 245–360 MPa
EN 10219 S235 / S355	Structural Steel	≥ 235–355 MPa

Dimensions

ERW pipe comes in a variety of sizes, ranging from ½ inch to 16 inches. Each size has its own technical specifications, including outer diameter, wall thickness, and tolerances. Wall thickness must meet certain standards, such as ASTM A53, which stipulates a maximum wall thickness of 12.5% of the pipe's outer diameter. Tolerances for outer diameter and wall thickness vary by manufacturer.

Form Factor

ERW pipe can be bent into a variety of shapes depending on the application. Common shapes include round, square, and rectangular. Other shapes, such as U-bends and swept elbows, can also be created by adjusting the internal shape of the pipe. Bend specifications depend on the material used and the required bend radius.

Round pipe: The most common, suitable for fluid transport;

Square pipe: Used in building frames and mechanical structures;

Rectangular pipe: Used in bridges and steel structure supports;

Special shapes (U-bends, elbows, swept elbows): Customizable to accommodate complex piping.

Weight Specification

ERW pipe is typically sold by weight, so it is important to understand its weight specifications. Weight calculations depend on the pipe's material composition, dimensions, and wall thickness. Pipe with thicker walls is generally heavier than thinner, smaller walls. 

The weight of ERW pipe (per unit length) can be calculated using the following formula:

W = 0.02466 × (D − t) × t

Where:

W = Weight (kg/m)

D = Outside Diameter (mm)

t = Wall Thickness (mm)

For example, a 6" (DN150) Sch40 ERW pipe has:

Outer Diameter 168.3mm, Wall Thickness 7.11mm → Weight approximately 22.85 kg/m

Parameters to Consider When Selecting ERW Pipe

When selecting ERW pipe for a specific application, certain parameters should be considered. These include Nominal Pipe Size (NPS), Wall Thickness (WT), Material Grade, Coating Type, and Hydrostatic Test Pressure.

 

1. Nominal Size and Wall Thickness

Nominal pipe size and wall thickness are the two most important parameters when selecting ERW pipe, as they determine the pipe's maximum capacity and pressure rating.

 

2. Materials and Coatings

The pipe material grade should be selected based on the application and expected operating conditions. The coating type should also be selected based on the pipe installation environment.

 

3. Inner Diameter

The inner diameter size of ERW pipe depends on the number of times the pipe is rolled into a tubular shape and will affect the overall strength and pressure rating of the pipe.

 

4. Hydrostatic Test Pressure

Manufacturers establish hydrostatic test pressure specifications to ensure ERW pipe complies with relevant standards.

 

5. Other Variables

There are several other variables that should be considered when specifying ERW piping. These include face type, thread type and bore diameter.

The end face type can be from plain end to beveled end or pipe  flange, and the thread type should be selected according to the intended use of the pipe. 

It is also important to consider the pressure, temperature and chemical resistance of the pipe, as well as its load carrying capacity.

Conclusion

ERW piping specifications and models are an essential part of many industrial systems and processes. Knowing the different types of plumbing available and their technical specifications is critical to choosing the right plumbing for the job. ERW piping comes in a variety of materials, sizes, shapes, and weights, and it is important to consider material, size, shape, weight, and design considerations when selecting piping.

Read more: The difference between erw and seamless black steel pipe