What Is ERW Steel Pipe (electric resistance welded)

erw carbon steel pipe

ERW pipe refers to a kind of high-frequency Electric Resistance Welding steel pipe. ERW pipe is divided into two forms of AC welding and DC welding, TUSPIPE’s high frequency welding is mainly used to produce thin-walled and normal wall thickness steel pipe, ERW pipe is an advanced performance, leading quality and cost-effective pipe for oil and gas storage and transportation, and it is ideal for most of the mechanical processing. 

The erw material of erw pipe full form final product is between welded steel pipe and seamless material, and because of this, it is smoother and the surface texture is more consistent, so there are no obvious welds.

The surface of the ERW steel pipe is uncoated, the color is semi-smooth dark gray, and the weld is located inside.

ERW Steel Pipe Process


erw pipe Uncoiler

The incoming coil is peeled and unrolled before being placed in a press roll. Flatten to remove coil groups to produce flat steel strips.

Uncoiler: plate width  200-1600mm, plate thickness 3-13mm, outer diameter: 2000mm, inner diameter: 750mm.


erw pipe Accumulating

The ends of the coil are joined together by a butt weld to form a continuous strip.Slitting blades and milling edges trim strip edges to provide the precise strip width required during molding and ERW seam welding.

Clamping and leveling machine: width of steel plate: 200-1600mm, thickness of steel plate: 3-13mm


ERW PIPE-forming

The forming process begins with the decomposition channel, where the material is gradually bent from a flat steel strip into a round tube to be submitted to the ERW seam welder.

Forming machine: diameterФ89-Ф426mm, thickness3.5-12.7mm

High-frequency Welding


As the material passes through the welding mill frame, a high-frequency current flows into the strip edge through a conductive nozzle, generating the heat needed to bond the strip edge together.

Solid state high frequency welding machine:diameterФ89-Ф426mm,thickness3.5-12.7mm

Dual Heat Treatment


Heat treatment is an important part of pipe processing, pipe after high frequency welding, too fast or too slow cooling will bring damage to the performance of the pipe, heat treatment can keep the pipe performance in the best quality.

Linear induction heating device:diameterФ89-Ф426mm,thickness3.5-12.7mm



The sizing section extrudes the welded pipe to the exact roundness, outside diameter and straightness tolerances specified by the customer.

Flat head chamfering machine: diameterФ89-Ф426mm, thickness3.5-12.7mm

Quality Control


After the welding is complete, quality control (QC) is carried out for visual inspection of the finished pipe, and if necessary, further ultrasonic (UT) testing is performed to ensure that the weld is free of defects.

To watch more tuspipe production food, you can go to our youtube

ERW Pipe Dimensions

ERW steel pipe has the characteristics of using hot rolled coil as raw material, and the wall thickness can be controlled at ±0.2mm. The two ends of the steel pipe are repaired according to the American APl standard or GB/T9711.1 standard, and the delivery size is set.

Outer diameter: 21.3 mm to 660 mm
Thickness: 1.0 mm to 20 mm
Length: 3 m to 12 m, or customized length can be provided according to customer requirements
End: flat end, inclined end, thread.

ERW Steel Pipe Mechanical Property

It is different from the welding process of ordinary welded pipes, and the weld is made of the base material of the steel strip body, and its mechanical strength is better than that of ordinary welding.

Mechanical Information
Ultimate tensile strength 132,000 psi 602 mpa
Yield tensile strength 74,185 psi 512 mpa
Rockwell hardness B75
Brinell Hardness 90

Difference Between ERW and Seamless Pipe

Welds: The main difference between seamless pipe and an ERW pipe is that a seamless pipe is manufactured without welds or joints, whereas an ERW pipe is manufactured from longitudinally welded steel parts, with welds having a higher impact toughness than a seamless pipe and being highly durable with high concentricity and uniform wall thickness.

Cost-effectiveness:Both of these steel pipes can meet the conditions of use in harsh environments, but relatively speaking, erw production costs are lower, and this product allows manufacturers to buy the right steel pipe at a reasonable price.

Characteristics: erw steel pipe is cold rolled after hot rolling process, which has excellent corrosion and oxidation resistance. And after strict heat treatment, the weld properties are consistent with the basic material properties. Welded pipe has normal pipe ends, threaded pipe ends, slant pipe ends and other pipe ends.

High dimensional accuracy: the diameter and wall thickness deviation of welded pipe is much smaller than that of seamless pipe, and the surface is smooth.

These unique properties can be easily customized to different shapes and sizes to meet customer needs in all directions.
In short, the resistance welding process has high production efficiency, relatively low manufacturing costs, and is suitable for large-scale production, saving materials and easy automation.
In addition, erw has the advantages of easy welding, cutting, forming, drilling and machining, which makes erw a very reliable and popular steel pipe in engineering.

Our Advantages

  1. Over 25 years of experience in pipeline production and installation.
  2. Comprehensive inspection equipment.
  3. Independent product serial numbers for traceability.
  4. Advanced production equipment – Seamer high-frequency welding machine from the United States.
  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
  6. Wide range of products – independently developed solar torque tubes, highly favored in the European market.
  7. Customers spread across the globe.
  8. Excellent after-sales service and sense of responsibility.

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