The Difference Between ERW and EFW Pipe

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Two of the most common methods to produce pipe are Electric Resistance Welding (ERW), and Electric Fusion Welding (EFW). Both processes involve a coil of steel being continuously fed through a series of rollers/dies which shape the flat steel into the desired shape of the pipe. 

How the edges of the steel plate are joined together are what makes the ERW and EFW processes different. 

Over the course of this Blog, we will discuss both processes, the benefits each have, and why you would use ERW or EFW pipe.

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ERW vs EFW Pipe

Forming Process

As stated above, once the flat steel plate has been formed into the pipe shape the two edges need to be joined together.

In an ERW process, a high frequency electrical current is used to heat the edges of the steel plate just before the final shaping rollers/dies join them together to create the circular pipe shape. 

A high frequency Is prevalent in modern piping because the low frequency current had several deformities including: seam corrosion, hook cracks and the seam bonding was inadequate.  

ERW pipe has a weld seam that runs along the length of the pipe. ERW pipe will either clean/trim the weld seam, or just use a roller/die to smooth out the seam to match the outside diameter; leaving a visible weld seam on the inside diameter.

For EFW (also known as electron beam welding), an electron beam (laser) is used to heat the edges prior to the rollers/dies joining them together. 

EFW pipe also has a weld seam that runs along the length of the pipe.  This seam is cleaned/trimmed on the outside, and inside, diameter for EFW pipe.

EFW pipe is a cost effective solution for environments that require high pressure and are corrosive. This type of pipe has better strength and durability. This pipe is stronger, denser and more uniform as compared to ERW because of its fusion method.

Finally, the pipe continues to go through another few sets of rollers/dies to ensure its final shape before each section of pipe is cut to length.

Benefits of ERW

The ERW manufacturing process is highly efficient and cost-effective. Machinery required for ERW pipe is very common, and with proper care and maintenance can run for decades. As a result, it is the predominant method for producing pipe in the PVF industry. 

Benefits of EFW

The fusion process in EFW manufacturing produces a much narrower &#;heat affected zone&#; in the pipe than the ERW process. This translates to a better uniformity of the metal in the pipe, and a higher pressure rating than ERW. 

Combining the higher pressure, with a still cost-effective end product (the initial tooling investment is greater for EFW pipe), means that EFW pipe can be looked at as a substitute for seamless pipe in certain applications.

What is ERW Pipe

Used For?

Just as ERW is the predominant pipe manufacturing process, ERW pipe can be found in just about every industry where fluid/media needs to be moved from one location to another. 

Common industries where you would find ERW pipe include: plumbing, HVAC, fire suppression, commercial, aviation, aerospace, automotive, rail, electronics, energy, oil & gas, and industrial.

What is EFW Pipe

Used For?

Being viewed as a cost-effective alternative to seamless pipe means that EFW can be used in higher pressure, more corrosive applications where ERW could not be considered. Industries such as petrochemical, textile, food & processing and chemical processing can utilize EFW in areas of their pipelines.

ERW Pipe Specification

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• ERW pipe sizes range from ½&#; &#; 48&#;

• Manufactured in several schedulesranging from schedule 5 to schedule 160 as well as schedule XXS and XS. The schedule used is dependent upon the application and pressure of the piping system.  

• most common alloys ERW pipe is manufactured from are

  TheERW pipe is manufactured from are stainless steel and carbon steel

• Ends: plain, bevelled, threaded

• Industry Standards & Specifications:

• ASTM A178: Standard Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes

EFW Pipe Specifications

• EFW pipe sizes

  range from 1/8&#; through 100&#;.   The availability of these diameters depends on the ASTM specification.  

• Manufactured in several schedules including schedule 10, schedule 40 and schedule 80, etc. These schedules are used in different applications based on the pressure requirements of the system they will be used in.  

• Available in several alloys such as stainless steel, high nickel alloy and carbon steel. This gives flexibility to those installing piping systems. 

• Surface finishes: HF pickled, matt polish, sandblast

• Ends: plain, bevelled, threaded

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• Industry Standards & Specifications:

• ASTM A672: Standard Specification for Electric-Fusion-Welded Steel Pipe for High-Pressure Service at Moderate Temperatures

• ASTM A691: Standard Specification for Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures

Other pipe standards, such as ASTM A53, ASTM A252, and ASTM A312 would apply to both ERW and EFW pipe.

It is important to understand the differences between ERW and EFW pipe to ensure that you are using the correct pipe for your system&#;s application. Pressure, corrosive environment and budget are just some of the considerations when determining which type of pipe to use. 

Always consult your project and engineering firm prior to installing any pipe into your system to ensure a safe and proper installation. 

STILL HAVE QUESTIONS?

Author:  Kimberly Wallingford, Director of Marketing - Merit Brass and Marcus Estrella, Director of Product Line Management - Merit Brass

Sources:

https://www.nucorskyline.com/globalnav/products/pipe/erw#:~:text=Electric%20resistance%20welded%20(ERW)%20pipe,are%20limited%20to%%20inches.

SAW vs ERW and EFW Welded Steel Pipe (hu-steel.com)

https://www.oshwin.com/stainless-steel-efw-pipe.html

https://www.husteel.com/news355_146.html#:~:text=EFW%20steel%20pipe%20(Electric%20Fusion,the%20formation%20of%20the%20weld.

Stainless Steel EFW Pipe | SS 304/316 EFW Pipe (oshwin.com)

PHMSA: Stakeholder Communications - Manufacturing Process (dot.gov)

What are the main equipment in the erw pipe production line? (eastern-steels.com)

Everything You Need to Know About ERW Pipes By Santosh Steels

ERW (Electric Resistance Welding) Stainless Steel Pipes: Features and Applications

Electric Resistance Welding ERW Stainless Steel pipes are pipes manufactured from strips or coils. They are formed from the ribbon of steel pulled through a series of rollers and are formed into a tube, which is then fused through an electric charge. The ERW pipe is electric-resistant and welded from either strips or coils in a longitudinal direction to add strength to the pipe.

ERW pipe is a welding process where metal parts in contact are permanently joined by heating them with an electric current, melting the metal at the joint. Electric resistance welding is widely used for example, in the manufacture of steel pipe and in the assembly of bodies for automobiles

ERW pipe is widely used in a variety of industries, such as engineering, fencing, line pipes, scaffolding, and so on. Some of the most common uses for ERW pipes are in agriculture and irrigation, particularly in sewerage systems, water mains, industrial water lines, deep tube wells, plant piping, and so on. They are also widely used in gas pipelines, particularly in the manufacture of natural gas, LPG, and other non-toxic gas pipelines.

Methods of Manufacturing ERW Pipe

There are different dimensions and standards for those pipes. The ERW Pipe Schedule 40 Pipe is one of the medium-range schedules that allow medium-range pressure containment of the pipes. The schedules govern the wall thickness for various outer diameter sizes of the pipes. 316-grade steel pipe is one of the most used pipes in this segment

ERW chrome steel tubes and stainless steel electrical resistance welding pipes in other material grades than the 304 stainless steel tubes. These pipes are mostly used in water, oil, and other low-pressure transportation of liquids.

Special features of ERW Pipe

• High-Strength Corrosion Resistance

• High Malleability

• Superior Strength

• Durable and Sturdy

ERW Pipe Applications

The main advantage is the strength along the length of the pipes. For higher strength, the chrome steel ERW Square Pipe is employed in some important applications.

ERW pipes are passed through numerous tests to ensure high-quality products. ERW pipes are cost-effective with good tolerance and less weight. These pipes have their usage in distinct fields. Some of the popular applications of ERW Pipe are as follows:

 Oil and Gas Industry

This industry is one of the biggest contributors to development and the economy. The end products are fuel oil and gasoline. The 3 processes involved are as follows:

1. Upstream: This process involves the survey and study of natural gas and crude oil and drilling.

2. Midstream: The crude oil is shifted, stored, and prepared in a cleanser. In shifting or transportation processes, pipelines and oil tankers can be used.

3. Downstream: This process includes purifying crude oil filters and cleansing natural gas.

 Automotive Industry of ERW Pipe

In the Automotive industry, stainless steel is most likely to be used in the exhaust systems of vehicles

The durability of a stainless steel exhaust is its key selling feature. These exhausts are sturdy and long-lasting due to the substance; consider them an investment. Absolute steel is rust and corrosion-resistant in addition to being strong and durable, so that's one less thing to worry about. Due to their high cost, stainless steel exhausts normally come with a warranty. Any issues can be promptly solved, so it's no surprise that these stainless

Thermal Powers

Basically, in thermal power plants, stainless steel is found in every part of the system, irrespective of the size of the department. For instance, pressure tubes are a necessity for ensuring safe functions at the plant. The main function is to circulate coolant in the reactor.

1. Containment vessels 

The containment vessel is one of the biggest components in a nuclear plant and is made of stainless steel. The primary function of this component is to protect the reactor from outside factors and to save the workers from the side effects of radiation

2. Fuel and Coolants 

Uranium oxide balls are stored in tubes to power the plant, while coolant circulates continuously around the core to prevent it from overheating.

3. Pressure tubes 

These can hold fuel or coolants (see above). Larger vessels are used by some plants to contain their moderator or coolant. In either case, these tubes or vessels are typically made of stainless steel

4. Steam generators 

When the reactor generates heat, a pressurized coolant converts it to steam, which powers the turbines. Most reactors have multiple steam generators.

5.  Moderators 

The moderator (graphite or water) sits within the reactor's core and slows the neutrons produced by fission.

6. Engineering purposes

  Fencing, Line Pipes, and Scaffolding

  ERW pipe and tubes are also used for various engineering purposes, including fencing, scaffolding, line pipes, etc. Stainless steel ERW pipe for applications in the petrochemical, pharmaceutical, oil and gas, chemical, and food processing industries.

Why Choose Santosh Steels For your ERW Pipe Needs

You wish to purchase a stainless steel ERW pipe in bulk to fulfill a variety of engineering and industrial application needs. So why not contact Santosh Steels? We can provide you with a profitable deal. Professionals in the industry are engaged in providing the best possible service and product quality to their clients. There is a broad range of products available to meet all applications effectively. We manufacture stainless steel ERW pipe using high-quality raw materials sourced from reputed companies in the country. We adhere to ASTM and other international standards. Feel free to contact us for any kind of stainless steel pipe or tube you need.

The company is the world’s best Erw Steel Pipe supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.