ERW Steel Pipes

A: ERW steel pipe, full name Electric Resistance Welding, is a steel pipe produced by using the skin effect and proximity effect of high-frequency current to heat and melt the edge of the tube blank, and pressure welding is performed under the action of the extrusion roller.

A: ERW steel pipes are mainly divided into two forms: ERW AC welded steel pipes and ERW DC welded steel pipes. According to the frequency, they are divided into low-frequency welding, medium-frequency welding, ultra-medium-frequency welding and high-frequency welding.

A: ERW steel pipes are widely used in oil and gas storage and transportation, power industry, tap water engineering, petrochemical industry, chemical industry, agricultural irrigation, urban construction and other fields. They can be used as wire casings, liquid conveying pipes, gas conveying pipes, structural pipes, etc.

A: The production process of ERW steel pipe includes longitudinal shearing, uncoiling, strip leveling, head and tail shearing, strip butt welding, loop storage, forming, welding, burr removal, sizing, flaw detection, fly cutting, initial inspection, steel pipe straightening, pipe section processing, hydraulic pressure test, flaw detection, printing and coating.

A: The welding method of ERW steel pipe has the characteristics of high production efficiency, low cost, material saving and easy automation.

A: The quality of ERW steel pipe weld is guaranteed by strict flaw detection, including ultrasonic flaw detection, magnetic leakage flaw detection, etc., to ensure that the weld is defect-free.

A: The wall thickness and diameter specifications of ERW steel pipe are diverse, depending on the production standards and customer needs. Generally speaking, the nominal diameter of the welded pipe is 6150mm and the nominal wall thickness is 2.06.0mm.

A: The length of ERW steel pipe is usually 4~10 meters, and it can be shipped in fixed length or multiple lengths.

A: The surface of ERW steel pipe should be smooth, and no defects such as folding, cracks, delamination, and lap welding are allowed. Minor defects such as scratches, scrapes, weld dislocation, burns and scarring that do not exceed the negative deviation of the wall thickness are allowed.

A: The hardness test of ERW steel pipe can be carried out by Vickers hardness tester, Rockwell hardness tester or surface Rockwell hardness tester. The test needs to be carried out in the designated area to ensure the accuracy of the test results.

A: The quenching and tempering heat treatment of ERW steel pipe is usually carried out by induction heating or flame heating. The main technical parameters are surface hardness, local hardness and effective hardened layer depth.

A: Lack of fusion is one of the common defects of ERW steel pipes, which has a great impact on the strength and performance of steel pipes. According to its characteristics, it can be divided into three categories: complete lack of fusion, partial lack of fusion and incomplete fusion (such as cold welding).

A: The causes of the lack of fusion defects in ERW steel pipes mainly include insufficient welding heat input, poor edge shape of strip steel, excessive bending deformation of the edge of the formed tube, and excessive pressure on the upper roller.

A: To avoid the lack of fusion defects in ERW steel pipes, it is necessary to optimize the welding process parameters to ensure sufficient welding heat input; at the same time, the edge of the strip steel should be well machined and pretreated to reduce the influence of impurities such as oxides.

A: The flaw detection of ERW steel pipes mainly includes ultrasonic flaw detection, magnetic flux leakage flaw detection, X-ray flaw detection and other methods. These methods can effectively detect defects and cracks inside the steel pipe.

A: The anti-corrosion treatment of ERW steel pipes mainly includes coating anti-corrosion, hot-dip galvanizing, inner wall lining and other methods. These methods can effectively extend the service life of steel pipes and improve their corrosion resistance.

A: The implementation standards of ERW steel pipes include international and domestic standards such as API 5L, API 5CT, ASTM, EN10219-2, GB/T9711, etc. These standards specify the requirements for the material, size, performance, etc. of steel pipes.

A: ERW steel pipes are steel pipes connected by welding, which have the advantages of high production efficiency and low cost; while seamless steel pipes are steel pipes directly drawn or extruded from a whole piece of metal material, which have the advantages of high strength and good pressure bearing capacity. There are differences between the two in production process, performance and application areas.

A: The production process of ERW steel pipes generates less waste, and the impact on the environment can be reduced through recycling and reuse. At the same time, ERW steel pipes also have good corrosion resistance and wear resistance during use, which is conducive to reducing environmental pollution.

A: Choosing a suitable ERW steel pipe requires considering factors such as usage scenarios, working pressure, medium properties, and temperature range. At the same time, it is also necessary to pay attention to the requirements of the steel pipe's material, size, performance, etc. to ensure that the selected steel pipe can meet the use requirements.