LSAW Steel Pipe Forming: UOE VS. JCOE

In the manufacturing process of the LSAW steel pipe（Longitudinal Submerged Arc Welded Steel Pipe）, the forming process directly determines the dimensional accuracy, mechanical properties, production efficiency, and cost structure of the steel pipe.

Currently, the most mature and representative forming methods in industrial applications mainly include UOE, JCOE, and HME, among which UOE and JCOE are the mainstream choices in international pipeline projects. This article will systematically compare and analyze UOE and JCOE LSAW steel pipes from multiple dimensions, including forming principles, process flow, technical characteristics, specification range, application scenarios, and selection.

LSAW Steel Pipe Forming Methods

LSAW steel pipes can be classified into the following types according to different forming methods:

1. UOE

After pre-bending the edges of a single steel plate, it undergoes U-forming, O-forming, internal welding, external welding, and mechanical cold expansion processes in sequence.

2. JCOE

Pre-welded and formed in the sequence "J-C-O-E," followed by cold expansion after welding.

3. HME

Formed using a mandrel rolling method in the sequence "C-C-O," followed by cold expansion after welding.

UOE Forming

The UOE steel pipe forming process is completed in three steps: pre-bending the edges, U-shaped press forming, and O-shaped press forming, with cold expansion of the entire pipe at the end.

1. UOE Forming Steps

U-forming: The steel plate is bent into a "U" shape using a hydraulic press.

O-forming: The "U" shape is further pressed into a circular "O" shape.

Diameter Expansion: The pipe diameter is expanded to the final diameter using mechanical or hydraulic methods, ensuring uniform dimensions and eliminating residual stress.

This forming unit is large and expensive. Each forming unit requires multiple sets of internal and external welding machines, resulting in high production efficiency.

2. Main Characteristics of the UOE Process

The forming and welding processes are separated, making it a non-continuous, single-piece production process.

It can produce thick-walled LSAW steel pipes, with a maximum wall thickness of approximately 40mm.

The weld length of LSAW steel pipes is only half that of spiral welded pipes for the same length, reducing the probability of weld defects.

High output; the output of one UOE unit is generally equivalent to the total output of 2-4 spiral welded pipe units.

The diameter expansion process improves the strength and dimensional accuracy of the steel pipe.

UOE steel pipes have straight seams, making pipeline laying and maintenance easier.

The equipment is larger than spiral welded pipe units, resulting in higher investment costs.

JCOE Forming

JCOE forming has three stages: first, the steel plate is pressed into a J-shape, then successively into a C-shape and an O-shape, where E represents diameter expansion.

1. JCOE Forming Steps

J-Shaping: The steel plate is bent into a "J" shape using a hydraulic press;

C-Shaping: The "J" shape is further bent into a "C" shape under pressure;

O-Shaping: The "C" shape is bent into a circular "O" shape, forming the basic shape of the pipe body;

Flanging: The O-shaped blank is welded internally and externally to form a complete weld seam.

The JCOE forming pipe-making unit is developed based on the UOE forming process. It borrows the working principle of the U-shape and implements the UOE forming process, significantly reducing the tonnage of the forming machine and thus saving on equipment investment.

The produced steel pipes are of the same quality as UOE welded pipes, but the output is lower than that of UOE welded pipe units. This process easily achieves automated control during forming, resulting in better product forming quality. JCOE forming equipment can be broadly divided into two types: bending forming and compression molding.

2. Main Characteristics of the JCOE Process

Each forming step in JCOE is completed on a large press. LSAW steel pipe shaping requires high technical skills, and the forming unit has a long occupancy time.

Due to the multiple forming processes, the processing efficiency is lower compared to the UOE process, but fewer molds are needed, resulting in lower equipment investment.

Because JCOE involves multi-step pressing, the dimensional accuracy of LSAW steel pipes is lower than that of UOE. Therefore, UOE steel pipes are more commonly used in marine pipelines.

LSAW Steel Pipe Forming: UOE vs JCOE

1. UOE LSAW Steel Pipe

Advantages

Extremely high production efficiency and output per unit time; stable product dimensions and excellent quality; perfectly meets the urgent needs of large-scale pipeline projects for standardized LSAW steel pipes.

Limitations

Significant equipment investment leads to higher production costs for small-batch orders; inflexible production size switching, unsuitable for small-batch, multi-specification orders.

Specifications

UOE LSAW Pipe

Outside Diameter：Φ508mm - 1118mm (20"- 44")

Wall Thickness: 6.0 - 25.4mm 1/4"-1"

Quality Standards: API、DNV、ISO、DEP、EN、ASTM、DIN、BS、JIS、GB、CSA

Length: 9 - 12.3m (30'- 40')

Grades: API 5L A-X90, GB/T9711 L190-L625

Typical Applications

Long-distance Oil and Gas Pipelines: Major domestic and international projects (e.g., transnational natural gas pipelines).

Subsea Pipelines: Offshore projects with stringent requirements for quality consistency and delivery speed.

Large mud pipelines.

2. JCOE LSAW Steel Pipe

Advantages

Flexible manufacturing process, easily producing non-standard sizes and large-diameter LSAW steel pipes; low mold cost and setup cost, suitable for small-batch orders; best suited for customized specifications.

Limitations

Lower production efficiency, not suitable for urgent large-scale projects; high product precision requirements necessitate the use of advanced equipment.

Specifications

JCOE LSAW Pipe

Outside Diameter：Φ406mm - 1626mm (16" - 64" )

Wall Thickness：6.0 - 75mm (1/4" - 3" )

Quality Standards：API、DNV、ISO、DEP、EN、ASTM、DIN、BS、JIS、GB、CSA

Length：3 - 12.5m ( 10'- 41' )

Grades：API 5L A-X100, GB/T9711 L190-L690

Typical Applications

Structural Piping: Airports, stadiums, bridges, and high-rise building foundations.

Process Piping: Used in power plants and petrochemical facilities. Water and heating networks (urban infrastructure).

Offshore platform structures.

How to Choose

When choosing an LSAW steel pipe manufacturing process, engineers or purchasing managers should consider the following factors:

1. Project Scale Determines Everything

If you need tens or hundreds of thousands of tons of piping of a single specification, the UOE process is more economical. If you only need a few thousand tons or a small number of different specifications of piping, the JCOE process is more ideal.

2. Standard Sizes vs. Custom Sizes

While they can indeed produce piping that meets standards and well-known grade standards (such as API 5L), JCOE is often the only option for a single diameter or wall thickness specification designed for a specific structure.

3. Project Type, Timeline, and Budget

An attractive feature of UOE is its ability to be mass-produced, thus reducing unit costs and speeding up delivery. JCOE is characterized by lower investment and is more suitable for customers with limited cost budgets or order volumes.