ERW pipe vs Seamless pipe cost

Date:2024-09-12Tags:ERW pipe, ERW steel pipe, Seamless pipe
Seamless steel pipes have hollow cross-sections and are widely used as pipelines for conveying fluids, such as oil, natural gas, coal gas, water and some solid materials. Compared with solid steel such as round steel, steel pipes are lighter in weight under the same bending and torsion strength, and are an economical cross-section steel.

" ERW steel pipe" is electric resistance welded pipe, referred to as ERW, which is used to convey vapor and liquid objects such as oil and natural gas. It can meet various requirements of high and low pressures and currently occupies a pivotal position in the world's transportation pipeline field.

What is the difference between erw pipe and seamless pipe?

As the name suggests, a pipe that is not constructed using welds is called a seamless pipe. The surface of the welded pipe has a longitudinal weld. In addition to the construction method, the pressure capacity, cost and application of each pipe are also different.

Different quality requirements

Seamless steel pipes have high quality requirements, and must be free of internal defects, smooth appearance and burrs. However, due to the limitations of the production method, defects such as cracks and pores in the welding parts of ERW welded steel pipes are difficult to avoid. High-quality seamless steel pipes require high costs for raw materials and precision processing, and the price is correspondingly higher.

Price Differences

Seamless steel pipes are more expensive than ERW steel pipes and have better quality. The price of seamless steel pipes of the same specification is generally about 30% higher than that of welded pipes, and the price difference is even greater for large diameters. The stress required for seamless steel pipes can be much higher, while welded steel pipes are generally around 10Mpa, so seamless steel pipes are more expensive.

Cost Differences Between Seamless and ERW Pipes

Since the manufacturing process of seamless pipes is longer and there are more steps, the cost of seamless pipes is always higher than that of welded pipes. ERW pipes are made of cold-formed sheets and then joined together by high-frequency welding, which is a relatively simple process and costs only a fraction of that of seamless pipes.


Aspect Seamless Pipe ERW Pipe
Manufacturing Extruded from a solid billet Formed and welded from a steel coil
Strength Higher due to lack of seam Slightly lower, but sufficient for many uses
Pressure Rating Can handle higher pressure Suitable for moderate pressure applications
Temperature Suitable for high-temperature environments Generally used in lower temperature environments
Cost More expensive due to complex manufacturing More cost-effective
Applications Oil and gas, power generation, high-pressure systems Water pipelines, structural applications, automotive
Uniformity Consistent structure throughout Consistent dimensions but with a welded seam

Different Manufacturing Processes for Seamless and ERW Pipes

Electric resistance welded pipes, or ERW pipes for short, are produced by cold-forming steel sheets into cylindrical shapes. After cold forming, an electric current is passed through the two edges of the steel sheet. The current heats the cold-formed steel sheet to a certain temperature, causing the edges to form a bond synchronously. The bond formed in this welding process does not require the use of welding filler materials. To achieve the highest quality welds, the high frequency ERW process is considered the most commercially viable option.

Unlike welded pipes, the process of manufacturing seamless pipes is longer and more intensive. The process uses heat and several other operations to get the final product. The raw steel is first heated and cast into solid billets. These solid billets mold the original steel alloy into a cylindrical shape. After the cylindrical shape is achieved, the original steel pipe is rolled until a stretched and hollow product is formed. The center of this newly manufactured product is irregularly shaped. To achieve a more uniform surface and uniformly shaped hollow, a bullet-shaped perforator tip is driven into the center of the billet while rolling the billet.
ERW pipe


Why use seamless pipes instead of ERW pipes?

There are two benefits of using seamless pipes. First, the working pressure capacity of seamless pipes is 20% higher than that of ERW pipes because, unlike ERW pipes, applying higher pressures will not cause pipe failure or rupture. Another more popular reason to choose seamless pipes is that they are not susceptible to intergranular corrosion. The seam lines on welded pipes, especially the HAZ or heat affected weld zone, can be affected at the grain boundaries due to sensitization compared to seamless pipes. This can intensify intergranular corrosion, which can weaken the ERW tube.

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