Large-diameter thin-walled steel pipe mill line
Large diameter tube mill is used to produce straight seam welded steel pipes with outer diameters from 114 mm to over 500 mm, widely applied in structural, fluid transport, and construction piping.
Greatwall specializes in high-frequency welded pipe production lines for large-diameter, thin-walled steel pipes. The lines feature advanced control systems, reliable forming technology, and high efficiency, serving the construction, infrastructure, and petrochemical industries.
Each line is customized to customer needs. The pipes have a smooth appearance, high pressure resistance, and reduced weight, helping lower installation and material costs.
Process: loading → unwinding → straightening → clamping and leveling → shearing and welding →Accumulator→ forming, high-frequency extrusion welding, removing external (internal) burrs, weld polishing, weld flaw detection, water cooling, sizing, rough straightening → Saw cutting → conveyor rollers → automatic packaging → marking → inspection and collection → storage
High-Frequency Welding Technology: Stable and precise straight seam welding.
Adjustable Roll Forming: Accommodates a wide range of pipe diameters and thicknesses.
Servo-Controlled Flying Saw: Ensures high-accuracy cutting at full line speed.
Human-Machine Interface (HMI): Intuitive PLC control system for easy operation.
Thin-Wall Compatibility: Suitable for 1–6.0 mm wall thickness, optimizing material use.
High Production Speed: Up to 50 m/min depending on configuration.
| Model | Round tube | Tube Thickness | Production Speed | Welding Type |
|---|---|---|---|---|
| ERW180 | 50–180 mm | 1.2–3.0 mm | 15–50 m/min | High Frequency Welding |
| ERW230 | 76–230 mm | 1.8–5.0 mm | 15–50 m/min | High Frequency Welding |
| ERW325 | 114–325 mm | 1.6–5.0 mm | 15–50 m/min | High Frequency Welding |
The ERW180 line is suitable for manufacturers mainly producing Φ50–180 mm thin-wall steel pipes. Its relatively wide small-to-medium size range makes it suitable for structural tubing, mechanical applications and general industrial pipe production.
Choose the ERW230 when your production range needs to extend to approximately Φ230 mm, especially when thicker specifications up to around 5 mm are required. It provides a balance between production flexibility and large-diameter capability.
The ERW325 is designed for manufacturers focusing on large-diameter pipes up to Φ325 mm. It is suitable for steel structures, industrial frameworks, infrastructure and other applications requiring larger pipe sections.
If your required OD, wall thickness or steel grade falls outside these ranges, Great Wall can evaluate a customized ERW pipe mill solution.
| Application Area | Common Challenges | Greatwall Solutions |
|---|---|---|
| Construction & Building | Long-length pipe demand, consistent diameter | Continuous forming and HF welding stability |
| Infrastructure Projects | Pressure resistance, installation precision | Stronger weld seams, accurate sizing |
| Fluid Transport | Internal surface smoothness, corrosion risk | Thin-walled precision pipe forming |
| Steel Structure Fabrication | Load-bearing capacity | Thick-wall pipe forming with tight tolerance |
| Piling/Foundations | Pipe strength under heavy load | Uniform welding and OD consistency |
Target Pipe Size Range: Choose a model (e.g., ERW180 / ERW230 / ERW325) based on required OD and wall thickness.
Material Type: Compatible with carbon steel, low-alloy steel, and galvanized strip.
Production Speed: Consider speed requirements for daily output targets.
Factory Space: Greatwall offers layout design assistance based on space constraints.
Automation Level: All models support PLC + touch screen automation with optional remote monitoring.
Founded in 1999, specializes in ERW welded pipe equipment (HG, DLW, LW series)
Top 3 manufacturer in photovoltaic zinc-aluminum-magnesium bracket equipment in China
Serves 20+ provinces in China; partners with leading domestic and international companies
Exports to Saudi Arabia, Russia, USA, India, Egypt, Southeast Asia, and more
30,000+ m² factory with advanced CNC and assembly lines
CE certified with strict quality control
Offers turnkey services: design, manufacturing, installation, training, after-sales
Provides on-site installation, remote support, spare parts, and technical assistance
Parameter Display
Product Disaplay
The performance of a large diameter steel pipe mill should not be evaluated by maximum line speed alone.
Production efficiency is mainly affected by:
Finished pipe outside diameter
Wall thickness
Steel grade and yield strength
Strip width and coil condition
HF welding power
Required dimensional tolerance
Cut length
Finished pipe standard
Generally, larger pipe diameters, thicker walls and higher-strength materials require greater forming force and welding energy and may therefore operate at a lower production speed.
For accurate line selection, customers should provide the complete OD and wall thickness range instead of only the maximum pipe diameter.
Great Wall ERW tube mills can be configured for different steel materials according to forming strength, weldability and final pipe application.
Common materials include:
| Material | Typical Application |
| Low Carbon Steel | General structural and mechanical pipes |
| Q195 / Q235 or Equivalent | Construction, frameworks and general-purpose tubing |
| Q355 or Equivalent Low-Alloy Steel | Higher-strength structural applications |
| Hot-Rolled Steel | Structural and industrial pipe production |
| Cold-Rolled Steel | Applications requiring improved surface quality |
| Pre-Galvanized Steel | Outdoor and corrosion-resistant applications |
| High-Strength Steel | Engineering and lightweight structural applications |
Material yield strength should be confirmed before final machine design because it directly affects roll design, drive power, forming load and achievable production speed.
For coated strip, optional weld seam treatment or zinc-repair equipment can also be considered according to the production process.
The welding section is one of the key systems in an ERW pipe production line.
Great Wall can configure a solid-state high frequency welding system according to pipe diameter, wall thickness, material grade and target production speed.
The HF welding process continuously heats the strip edges and joins them under controlled squeeze pressure to form a longitudinal weld seam.
A complete welding section can include:
Solid-state HF welder
Induction coil
Impeder system
Squeeze roll unit
Welding power control
Cooling system
External bead removal
Optional internal bead removal
Weld seam monitoring equipment
HF welder power should not be selected according to pipe diameter alone.
The required power depends on:
Pipe OD + Wall Thickness + Steel Grade + Production Speed
For this reason, HF welder rated power should be confirmed individually for ERW180, ERW230 and ERW325 projects based on the customer's main production specifications.
For applications requiring higher weld quality control, the tube mill line can be equipped with online non-destructive testing systems.
Online eddy current testing can be used for continuous monitoring of surface and near-surface weld defects during production.
It is particularly useful for high-speed ERW tube production where continuous weld quality monitoring is required.
For higher pipe quality requirements, an online ultrasonic testing system can be added to inspect the longitudinal weld seam.
UT is suitable for detecting internal weld imperfections that may not be identified through visual inspection alone.
Depending on the finished pipe standard and application, the production line can also integrate or work with:
Weld seam inspection
OD measurement
Ovality inspection
Wall thickness inspection
Straightness inspection
Cut-length inspection
Hydrostatic testing
Offline ultrasonic testing
Full-body pipe inspection
NDT configuration should be selected according to the required finished pipe standard rather than treated as a fixed configuration for every tube mill line.
Stable forming, welding and sizing are essential for producing consistent large-diameter thin-wall steel pipes.
Important finished pipe quality factors include:
| Inspection Item | Quality Requirement |
| Outside Diameter | Stable OD throughout continuous production |
| Ovality | Controlled pipe roundness |
| Wall Thickness | Consistent thickness within material tolerance |
| Straightness | Reduced longitudinal bending |
| Weld Seam | Continuous and stable longitudinal weld |
| Surface Quality | Controlled scratches and roll marks |
| Cut Length | Accurate finished pipe length |
| Cut End | Clean and consistent pipe ends |
The final tolerance depends on pipe size, steel grade, production speed and applicable finished pipe standard.
Large-diameter thin-wall ERW pipes are mainly used where a relatively large pipe section is required without the weight and material consumption of heavy-wall pipe.
Typical applications include:
Large-diameter welded pipes are used for structural frames, warehouses, workshops, support structures and fabricated steel components.
Suitable for structural tubing, columns, supports and other general infrastructure applications.
Large pipe sections can be used for machinery structures, equipment frames and industrial support systems.
Large pipe diameters provide higher flow capacity for irrigation and general water transportation applications where the selected pipe specification is suitable.
ERW thin-wall pipes can be used for non-critical industrial conveying and fabrication applications according to applicable material and pipe standards.
Galvanized or coated steel pipes can be used for outdoor structural systems where improved corrosion resistance is required.
For high-pressure oil & gas pipelines, heavy-duty piling or thick-wall API pipe production, a heavier-duty ERW/API pipe mill configuration is normally required.
