ERW Tube Mill Line | Steel Pipe Mill | Unionindus

Φ8–Φ711mm

Tube Diameter

0.3–22mm

Thickness

10–120m/min

Line Speed

HF ERW

Welding

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What is an ERW tube mill line?

An ERW tube mill line continuously converts flat steel strip into longitudinally welded tube. Forming rolls shape the strip into an open tube, high-frequency current heats the strip edges, and squeeze rolls forge the edges together. The welded tube is then cooled, sized, straightened, cut and collected according to the required product specification.

Configure the complete line, not only the forming mill

A productive ERW project depends on how the entry section, accumulator, forming passes, high-frequency welder, sizing stands, cut-off and handling system work together. Unionindus starts from the complete pipe schedule and production plan so each section is selected for the same material and output window.

How ERW welding works

After the strip has been formed into an open round, high-frequency current concentrates heat at the approaching edges. Squeeze rolls apply pressure at the weld point to create the longitudinal bond. Stable edge presentation, heat input, squeeze pressure, mill speed and cooling are all important to repeatable weld quality.

Technical Specifications

Key ranges for Unionindus ERW tube mill lines. Model selection depends on the full pipe schedule, material strength and output target.

Item	Specification
Finished Shapes	Round, square, rectangular
Material Type	Carbon steel, low alloy steel, galvanized steel (when approved)
Tube Diameter	Φ8–Φ711 mm
Thickness	0.3–22 mm
Typical Speed	10–120 m/min (model and size dependent)
Welding	High-frequency electric resistance welding

Model Specifications

Typical Model Range (Reference)

Model	Tube Diameter (mm)	Thickness (mm)	Speed (m/min)
HG20	Φ8–Φ25	0.3–1.0	20–120
HG32	Φ10–Φ38	0.4–1.5	20–100
HG50	Φ16–Φ50	0.5–2.0	20–90
HG76	Φ25–Φ76	0.8–3.0	20–80
HG127	Φ48–Φ127	1.5–4.5	10–60
HG165	Φ76–Φ165	2.0–6.0	10–50
HG219	Φ89–Φ219	3.0–8.0	10–40

Machine Line Composition

Main equipment in an ERW tube mill line. Continuous entry, inspection and packing modules can be added according to the project.

Machine Unit	Function
Coil car and uncoiler	Load and feed slit steel coil into the line.
Leveler, shear and butt welder	Prepare strip ends and join successive coils when continuous operation is required.
Accumulator	Stores strip so the forming mill can keep running during coil changes.
Forming mill	Uses breakdown and fin passes to create the open tube and prepare the edges for welding.
High-frequency welder and squeeze section	Heats and forges the longitudinal seam.
External bead removal	Removes or controls the outer weld bead while the tube is online.
Cooling section	Stabilizes the welded tube before final sizing.
Sizing and straightening mill	Brings the product to its final round or shaped dimensions.
Flying saw or cold saw	Cuts the moving tube to the specified length.
Run-out and packing	Collects, stacks and optionally straps finished tube.

Key Machine Features

Core advantages of this production line

High efficiency

High-speed production with continuous entry options and minimal downtime during coil changes.

Precision and weld quality

Advanced HF welding technology for strong, uniform longitudinal seams.

Versatility

Capable of producing round, square and rectangular tubes across a wide size window.

Durable construction

Robust mill design for long-term reliable operation in industrial environments.

Automated control

Integrated PLC control for precise management of the production process.

Custom engineering

Line layout, tooling, inspection and packing can be tailored to your pipe schedule.

Application Scenarios

Typical use cases for this equipment

Construction

Structural pipes, scaffolding, fencing and general building applications.

Automotive

Exhaust pipes, chassis components, seat frames and related tubular parts.

Furniture

Table legs, chair frames and decorative tubing.

Infrastructure

Water pipes, gas pipes and electrical conduits within approved product standards.

Production Process

Typical high-frequency ERW tube mill flow: Coil loading → Uncoiling → Leveling → Strip-end shearing and joining → Accumulation → Breakdown forming → Fin-pass forming and seam guidance → High-frequency welding and squeezing → External bead removal → Cooling → Sizing and straightening → Online inspection when specified → Flying cut-off → Run-out, stacking and packing.

A simpler or more automated line can be proposed depending on coil-change requirements, product mix, quality plan, labor target and factory layout.

Why Choose Our ERW Tube Mill

Proven performance with complete-line engineering for carbon-steel and low-alloy welded tube.
Custom solutions tailored to pipe size, thickness, material strength and changeover needs.
Comprehensive support from installation and training through after-sales service.

Forming options

Conventional round-to-shape forming — welds in the round and sizes into square or rectangular sections downstream.
Direct forming to square or rectangular tube — may reduce tooling and changeover for suitable product ranges.
Flexible or shared-roll concepts — evaluated when frequent size changes justify added system complexity.

Buying Process

From pipe schedule to technical agreement:

Define the products: send the full size, thickness, material and annual-volume schedule.
Set acceptance: confirm tolerances, tests, cut quality and applicable product standard.
Select the process: review forming method, HF welding, cut-off, inspection and handling.
Review the plant plan: confirm utilities, line layout, foundations, access and operator requirements.
Finalize delivery: agree tooling, acceptance test, installation, training, documents and spare parts.

Frequently Asked Questions

What materials can an ERW tube mill process?+

ERW lines commonly process hot-rolled or cold-rolled carbon-steel strip. Low-alloy, higher-strength or coated materials may also be possible when the forming, drive, tooling and welding system are designed for their properties.

Can one ERW line produce round, square and rectangular tube?+

Yes, with suitable forming and sizing equipment. The size range, corner geometry, tooling strategy and changeover method must be selected from the complete product schedule.

What is the difference between an ERW tube mill and a stainless steel tube mill?+

An ERW page usually refers to high-frequency welded carbon-steel or low-alloy tube production. Stainless tube lines often use TIG, laser or plasma welding and may require different shielding, bead treatment, annealing and finishing.

Can the line produce galvanized steel pipe?+

It can be evaluated for pre-galvanized strip when coating protection and weld-seam restoration are included. A separate post-galvanizing plant is a different project scope.

How is the ERW mill model selected?+

Selection depends on the largest and smallest pipe, wall thickness, material strength, shape, output, forming method, welding power, cut-off and acceptance requirements rather than diameter alone.

What is the purpose of an accumulator?+

An accumulator stores strip between the entry section and the forming mill so production can continue while the next coil is prepared and joined. Its capacity is selected from line speed and coil-change time.

Which inspection systems can be included?+

Dimensional inspection, process monitoring, eddy-current, ultrasonic, hydrostatic or leak testing may be considered. The applicable product standard and quality plan determine the correct equipment.

What information is needed for a quotation?+

Provide the complete pipe schedule, material grade and strength, annual quantity, line-speed target, cut length, tolerances, testing standard, plant utilities and required automation.

Need a Quote for ERW Tube Mill Line?

Send us your profile drawing, material thickness and target output. Our team will recommend a suitable configuration.