Structural steel pipes include hot-rolled seamless steel pipes and welded steel pipes. Welded steel pipes are manufactured by coiling and welding steel strips. Depending on the pipe diameter, they can be divided into straight seam welded pipes and spiral welded pipes.
Seamless steel pipes for structural use are classified into hot-rolled and cold-drawn types according to the national standard Seamless Steel Pipes for Structural Purposes (GB/T 8162-2018). Cold-drawn pipes are limited to small diameters. Hot-rolled seamless steel pipes have outer diameters ranging from 32 mm to 630 mm and wall thicknesses from 2.5 mm to 75 mm. The main steel grades used are high-quality carbon structural steels, designated as 10, 20, etc.
Straight seam steel pipes, spiral steel pipes, and seamless steel pipes are common pipe materials used in industrial, civil, and municipal engineering construction. So what are the differences between straight seam steel pipes, spiral steel pipes, and seamless steel pipes? And how should they be selected for engineering applications?
Zhejiang Qibin Steel Pipe Technology Co., Ltd. Explains: What is a Spiral Steel Pipe?
A spiral steel pipe is a spiral seam steel pipe manufactured using hot-rolled steel strip coils as raw material. The strip is extruded into shape at ambient temperature and welded using an automatic double-wire, double-sided submerged arc welding process. To produce a spiral steel pipe, the steel strip is fed into a pipe welding unit, where it is gradually coiled through a series of rolling rollers, forming a round tube with an open gap. The compression of the squeezing rollers is adjusted to control the weld gap to 1–3 mm, ensuring that both sides of the weld are flat.
Spiral steel pipes are commonly used as fluid transmission pipelines for rainwater, sewage, petroleum, etc., and are often referred to as fluid pipes.
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