Roll tube

“Coiled pipe” is not a standard product name for steel pipes; rather, it’s a colloquial term used to describe either a manufacturing process or a specific product form. It carries two main meanings: As a raw material: It refers to steel coils—steel plates or strips that have been rolled and then coiled into cylindrical shapes. These coils serve as the raw material for manufacturing welded pipes. As a finished product: It refers to steel pipes that are produced by rolling and shaping steel plates or strips into cylindrical forms and then welding them together. In this context, “coiled pipe” typically refers specifically to spiral-welded pipes.

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Roll tube

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Product Description

I. What is a coil tube?

“Coiled tubing” is not a standard name for a steel pipe product; rather, it’s a colloquial term used to describe either a specific manufacturing process or a particular product form. It carries two main meanings:

As a production raw material, we’re referring to steel coils—steel plates or strips that have been rolled and then wound into coil form. These serve as the raw material for manufacturing welded pipes.

As a finished product: refers to steel pipes manufactured by rolling and shaping steel plates or steel strips and then welding them together. In this context, “rolled pipe” typically refers specifically to spiral-welded pipes.

II. Detailed Analysis of “Coiled Pipe” as a Finished Product (Spirally Welded Pipe)

This is the meaning often referred to by “scrolling,” especially in communication among non-professionals.

Key feature: The weld seam has a spiral shape—this is its distinctive visual characteristic.

Flexible material usage: Using steel strips of the same width, by adjusting the forming angle, it’s possible to produce steel pipes of various diameters.

Large caliber: It can produce pipes with very large diameters (up to several meters in diameter).

Lower costs: Compared to straight-seam welded pipes and seamless pipes, it has an advantage in production costs.

Main manufacturing process:

Uncoiling and Straightening: The steel coil, used as raw material, is uncoiled and straightened.

Edge trimming and butt joining: The edges of the steel strip are processed, and the ends of the front and rear steel strips are welded together to ensure continuous production.

Spiral forming: The steel strip is continuously rolled into a spiral shape by passing through a complex forming device.

Internal and external welding: During the steel pipe forming process, submerged arc welding technology is used to simultaneously weld both the internal and external seams.

Cutting and Inspection: Continuous steel pipes are cut into specified lengths, followed by subsequent processing and non-destructive testing.

III. Main Application Areas

Coiled pipes (helically welded pipes) are widely used in the following fields due to their large diameters and cost advantages:

1. Fluid transport:

Water conveyance: urban water supply and drainage networks, hydraulic engineering projects.

Oil and gas transportation: While early and some low-pressure oil and gas pipelines still use this method, today high-pressure main pipelines increasingly rely on straight-seam submerged arc welded pipes.

2. Structural support:

Pile-driving pipes: used for foundation pile driving in construction, bridges, and docks.

Support columns for large-scale structural elements such as bridge piers and utility tunnels.

3. Other uses:

Ventilation ducts: A factory ventilation system with large diameters is required.

IV. Differentiation from Other Steel Pipes

To better understand “coiled tubing,” let’s compare it with related steel pipes:

Feature	Coiled pipe (spiral welded pipe SSAW)	Longitudinal Seam Welded Pipe (LSAW/ERW)	Seamless pipe (SMLS)
Weld seam morphology	Spiral shape	A straight line	Seamless
Ingredients	Steel belt	Steel plate (LSAW) or steel strip (ERW)	Round steel billet
Main advantages	Large caliber, flexible material usage, low cost	Short weld seams, stable quality, and strong pressure-bearing capacity (especially for LSAW).	Good integrity, strong pressure-bearing capacity, and high safety.
Main disadvantage	The weld seam is long, residual stresses are relatively high, and the pressure-bearing capacity is relatively weak.	Limited diameter (especially for ERW), higher cost than spiral pipes.	High costs and limited caliber (large calibers are difficult to produce).
Typical applications	Water conveyance, piling, structural support, low-pressure delivery	High-pressure oil and gas transmission pipelines (LSAW), fluid conveyance (ERW)	High-pressure boilers, oil drilling and extraction, and critical components for mechanical structures