27.12.2021

What is a spiral steel pipe?

Spiral Welded Pipe Line is made by steel coil, extrusion forming under the normal temperature, then taken the technology of double wire and double-faced submerged-arc welded. Spiral steel pipe, also known as spiral or helix spiral steel pipe, is a low-carbon steel or low-alloy structural steel strip at a certain helix angle (called molding angle) rolled into a tube, and the tube is made of welded joints It can be produced with a narrow strip of large diameter pipe.

During molding process of spiral welded steel pipe, steel plate has uniform deformation and light residual stress, thus the surface has no scratches. Spiral steel pipe has more flexible thicknesses and diameters, especially in making high-grade thick pipes with small or medium aperture, these techniques has incomparable advantages in satisfying your needs.


Production process of spiral steel pipe

1. unwinding board probe: After entering the unwinding plate production line, the first full-board ultrasonic testing.

2. Leveling Milling: The flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.

3. shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.

4. butt cut: double-sided submerged arc welding using advanced technology to pre-welding, internal welding, outside welding. Ion foot cut to specification length Spiral Welded Pipe Mill use and so on.

5. visual inspection: by professional and technical personnel to some of the basic parameters to be checked.

6. The ultrasonic flaw detection: internal and external weld and weld on both sides of the base material 100% inspection.

7. X-ray detection: internal and external welds 100% X-ray industrial TV check image processing system to ensure that the use of detection sensitivity.


The first is to know the difference between ERW and HFW welding processes. High-Frequency Welded (ERW) Pipe Line welding process refers to the heat generated by the resistance of the current flowing through the connecting metal. Therefore, a large current is required to charge the entire surface of the steel plate or coil to the welding length. During ERW welding, the current flowing through the entire conductor is 50/60 Hz. ERW is the general term for electric resistance welded steel pipe. It can be divided into two types: alternating current welding (AC) and direct current welding (DC). According to the different frequency, AC welding can be divided into low frequency welding, intermediate frequency welding, ultra high frequency welding and high frequency welding. High frequency welding (HFW) is mainly used for ordinary or thin-walled steel pipes. It includes contact welding and induction welding. DC welding is usually used for small diameter steel pipes. Generally, HFW is one of ERW production methods, which uses high-frequency welding technology. Therefore, ERW steel pipe includes HFW steel pipe.


Cold Roll Forming Line consists of gradually and continuously forming a steel profile. The method consists initially unrolling the strip of a steel coil, whose width corresponds to the developed of the finished profile. This band, also called strip, is then engaged flat in a succession of several rolls called rollers whose shapes and numbers are variable depending on the complexity of the desired steel profile.

The forming of the profile is performed very gradually, we do not have to fear the cracks or even the breaks that occur in the cold bending to the press or stamping. Finally, although it is not a rolling, the operation produces a certain surface hardening known as the "skin effect". The manufacturing, initially limited to hot and cold rolled steel strip sections, has gradually expanded to include stainless steel and aluminum and copper alloy profiles.


Steel is an alloy of iron that is mixed with carbon which improves its strength and durability. Combine these properties with its low cost and you have a perfectly-suited alloy for a multitude of uses in various end applications, including (but not limited to) automotive, infrastructure, and appliance/HVAC.

Enter the role of steel processors. Steel processing companies like National Material Company provide manufacturers with the right steel material for their industry. This article will focus on the topic of steel Slitting Line and how the slitting process works.

Steel slitting is a steel manufacturing process wherein a coil of steel is slit into the lengths and widths specified by the end application. This process requires machinery lines equipped with a decoiler, slitter, and a recoiler — to achieve the end product: slit steel coils, or “mults.”


Pipe Endfacing and Beveling Machines are suitable for pipe applications to meet any internationally known standards, including those of API and AWWA. End Facing and Beveling Machines can be used with pipes produced by the electric resistance welding (ERW) process as well as pipes produced by the submerged arc welding (SAW) process.


Edge Miller machines can operate on both flat or rolled shapes with ranges up to 18000mm in length and 3 milling heads. Hydraulically retractable backstops assist plate alignment and reduce machine set-up time. Tight straightness tolerances meet automatic welding requirement for high productivity.

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