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What is the difference between straight steel pipe and spiral steel pipe?

What is straight steel pipe?

Straight seam steel pipe encompasses various types such as high-frequency straight seam, submerged arc straight seam, electric welded straight seam, and pipeline straight seam. High-frequency straight seam steel pipe harnesses the skin effect of high-frequency current to swiftly induce high temperature and external force at both ends of the steel plate. This results in a true electrode-less metal butt joint. Utilizing hot-rolled coil as its primary material, ERW steel pipe maintains precise control over wall thickness, typically within ±0.2mm.
Pipe ends are trimmed according to either American APL or GB/T9711.1 standards, with fixed conveying lengths. In recent times, ERW steel pipe has gained widespread adoption in urban pipeline network projects and within the natural gas industry, serving as the primary steel pipe for urban pipeline networks. Presently, ERW high-frequency straight seam steel pipe constitutes approximately 60% of the global steel pipe consumption.

What is spiral steel pipe?

Spiral steel pipe (SSAW) is manufactured using strip steel coils as the primary raw material, which are extruded at room temperature and welded using an automatic double-wire double-sided submerged arc welding process. The process involves feeding the strip steel into a welded pipe unit, where it passes through multiple rollers, gradually forming a round tube billet with an opening gap. By adjusting the reduction of the extrusion roller, the weld gap is controlled within the range of 1~3mm, ensuring both ends of the welding seam are flush. The distinctive appearance of spiral pipes includes spiral welding ribs, a characteristic resulting from its unique manufacturing process.

Difference between straight steel pipe and spiral steel pipe

What is the difference between straight steel pipe and spiral steel pipe
Straight steel pipe and spiral steel pipe are all kinds of welded steel pipes. They are widely used in national production and construction. Straight steel pipes and spiral steel pipes have many differences due to different production processes. The difference between seam steel pipe and spiral steel pipe. The production process of straight steel welded pipe is relatively simple. The main production processes include high-frequency welding straight seam steel pipe and submerged arc welding straight seam steel pipe. The straight steel pipe has high production efficiency, low cost and rapid development. The strength of spiral welded pipe is generally higher than that of straight welded pipe. The main production process is submerged arc welding. Spiral steel pipe can produce welded pipe with different pipe diameter with blank of the same width, and can also produce welded pipe with larger diameter with narrower blank. However, compared with the straight pipe of the same length, the weld length is increased by 30 to 100%, and the production speed is low. Therefore, most of the smaller diameter welded pipes are straight seam welded, and the large diameter welded pipes are mostly spiral welded. In the industry to produce larger diameter straight seam steel pipe will use T-welding technology, that is, a short length of straight seam steel pipe will be butt jointed to meet the length of the project, the probability of T-weld straight seam steel pipe defects is greatly improved, and T-welding The welding residual stress at the joint is large, and the weld metal tends to be in a three-direction stress state, increasing the possibility of cracking.
 

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