Steel pipes can be categorized based on welding methods, including arc-welded pipes, high-frequency or low-frequency resistance-welded pipes, gas-welded pipes, furnace-welded pipes, Bundy tubes, etc. Furthermore, they can be divided into longitudinally welded pipes and spiral steel pipes according to the shape of the weld seam. Electrically welded steel pipes are utilized in the oil drilling and machinery manufacturing industries.
Specifications for steel pipes range from Φ219 to Φ2032, with wall thicknesses varying from 5mm to 18mm, and materials including Q235, Q345, and grades X42-70.
A spiral welded steel pipe is produced by bending steel strips or plates into circular, square, or other shapes and then welding them together, resulting in a steel pipe with a visible seam on its surface.
Classification of Welded Steel Pipes:
By welding method: arc-welded pipes, high-frequency or low-frequency resistance-welded pipes, gas-welded pipes, furnace-welded pipes, Bundy tubes, etc.
By weld seam shape: longitudinally welded pipes and spiral welded pipes.
Electrically welded steel pipes are employed in oil drilling, machinery manufacturing, etc. Furnace-welded pipes can serve as water and gas pipes, while large-diameter longitudinally welded pipes are used for high-pressure oil and gas transportation. Spiral welded pipes are suitable for oil and gas transmission, pipe piles, bridge piers, etc.
Welded steel pipes are generally cheaper and more productive than seamless steel pipes. Longitudinally welded pipes boast simple production processes, high efficiency, low costs, and rapid development. On the other hand, spiral welded pipes typically exhibit higher strength than their longitudinal counterparts, enabling the production of larger-diameter pipes from narrower strips. They also allow for the creation of pipes with varying diameters from the same strip width.
However, compared to longitudinal pipes of the same length, spiral welded pipes have a 30~100% longer weld seam, resulting in a slower production speed. Therefore, smaller-diameter pipes mostly adopt longitudinal welding, while larger-diameter pipes prefer spiral welding. Spiral submerged arc welded steel pipes are manufactured by spirally bending hot-rolled steel strips and welding the inner and outer seams using the submerged arc automatic welding method.
Reasons for the Widespread Application of Spiral Steel Pipes in Large-Diameter Production:
By altering the forming angle, various diameters of steel pipes can be produced from the same strip width.
Due to continuous bending formation, the cut-to-length of steel pipes is not limited.
The spiral weld seam is evenly distributed across the entire circumference of the pipe, leading to high dimensional accuracy and strength.
Easily adjustable dimensions make them suitable for the production of small-batch, multi-variety steel pipes.
