Longitudinal seam steel pipes can be divided into electric resistance welded straight seam steel pipes and submerged arc welded straight seam steel pipes in terms of welding process. Among them, electric resistance welded straight seam steel pipes are divided into high frequency welded straight seam steel pipes, medium frequency welded straight seam steel pipes, and low frequency welded straight seam steel pipes. The submerged arc welded straight seam steel pipe is also called the double-sided submerged arc welded straight seam steel pipe or LSAW straight seam steel pipe, where LSAW is (Longitudinally Submerged Arc Welding abbreviated as LSAW). Resistance welded straight seam steel pipe is also called ERW straight seam steel pipe. ERW is (Electric Resistance Welding, abbreviated as ERW).The following is the production method of each welding process:
1. High frequency welded straight seam steel pipe is also called ERW straight seam steel pipe
ERW pipe is a general term for electric resistance welded steel pipe. ERW (Electric Resistance Welding) corresponds to the first letter of the English word. Electric resistance welded steel pipes are divided into two types: AC welded steel pipe and DC welded steel pipe.
AC welding is divided into low frequency welding, intermediate frequency welding, super intermediate frequency welding and high frequency welding according to the different frequency. High-frequency welding is mainly used for the production of thin-walled steel pipes or ordinary thick-walled steel pipes. High-frequency welding is divided into contact welding and induction welding. DC welding is generally used for steel pipes with small diameters.
Therefore, comprehensively speaking, the high-frequency welded pipe is included in the ERW welded pipe, which is a kind of ERW welded pipe produced by the high-frequency welding process. ERW longitudinally welded pipe is a steel pipe with advanced performance, leading quality and relatively economical product in the field of oil and gas storage and transportation.
The probability of defects in ERW straight seam steel pipes is small; it can transport wet sour natural gas conditionally; after the diameter is expanded, the geometrical dimensional accuracy of the steel pipe is high; the welding is carried out in a straight line in the horizontal position after the forming is completed. Therefore, the wrong side, The slits, pipe diameter and circumference are well controlled, and the welding quality is excellent. Products are widely used in petroleum, natural gas, coal gas, coal mines, machinery, electricity, piling and other purposes.
2. Submerged arc welding straight seam steel pipe is also called double-sided submerged arc welding straight seam steel pipe or LSAW straight seam steel pipe
LSAW steel pipe (Longitudinally Submerged Arc Welding) is a professional expression term for LSAW steel pipe. LSAW steel pipe is produced by using a single medium-thick plate as raw material, pressing (rolling) the steel plate in a mold or forming machine into a tube blank, using double-sided submerged arc welding and expanding the diameter. The finished product has a wide range of specifications, and the weld has good toughness, plasticity, uniformity and compactness. It has the advantages of large pipe diameter, pipe wall thickness, high pressure resistance, low temperature resistance and strong corrosion resistance. In the construction of high-strength, high-quality long-distance oil and gas pipelines, most of the steel pipes required are large-diameter thick-walled LSAW pipes. According to API standards, in large-scale oil and gas pipelines, when passing through Class 1 and Class 2 areas such as alpine regions, seabeds, and densely populated urban areas, LSAW pipe is the only designated applicable pipe type.
Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.
ASTM A53 Grade B is the material under the American steel pipe standard, API 5L Gr.B is also the American standard material, A53 GR.B ERW refers to the electric resistance welded steel pipe of A53 GR.B; API 5L GR.B Welded refers to the material Welded steel pipe of API 5L GR.B.https://www.permanentsteel.com/productshow/erw-steel-pipe.html