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You landed here after typing erw tube mill into a search box, and every page looks the same: one long machine and a table of models nobody will confirm. Will this line make the tube you sell, at the wall thickness your customers ask for, with a weld that survives the first hydrostatic test? We are the sales engineers who walk buyers through that, and we start with your strip data, not a price.
This guide follows the strip from coil to finished pipe. We show you where the weld is made, how to read a model table without over-buying, and which figures we need in writing before we quote. When a number is not published on our site, we write to be confirmed in writing instead of guessing.
A flat steel coil goes in and a welded tube comes out. Buyers often picture one machine doing it all. An ERW tube mill is a sequence of stations. We load the coil, flatten the strip, join strip ends, and hold a loop in an accumulator so the line keeps running during a coil change.
Forming rolls bend the strip into an open tube. High frequency current heats the two edges, squeeze rolls press them together, and the weld is made without filler metal. Everything downstream protects that joint. Our reference sequence runs from strip joining through forming, H.F. welding, scarfing, cooling, eddy current testing, sizing, straightening, ultrasonic testing, cutting and hydrostatic testing.
Read that as a sequence, not a shopping list. We say up front the process is for reference and can be customised. Our primer on how the line works covers it in fewer words.
The weld is the whole game. High frequency current concentrates at the strip edges through the skin effect and the proximity effect, heating them to welding temperature while the rest of the strip stays cooler. Squeeze rolls then forge the edges together. A common mistake is blaming the welder for a seam problem that actually started with bad strip edges or the wrong forming setup.
Our high frequency induction welder runs on a PLC with interlock control and fault diagnosis. The solid state series uses a modular design and electronic load matching. We do not publish power in kW, frequency in kHz, or efficiency figures, so we will not quote them.
The impeder and ferrite core sit inside the tube and shape where current flows. Our technical articles note a ferrite core length allowance of 15 to 40 mm for the diverging magnetic field. We confirm the setup during commissioning with your coil.
Forming turns flat strip into a round shell; sizing brings it back to the outside diameter you promised a customer. Scarfing removes the inner and external bead left by the weld, and seam ironing smooths the joint. Forming sets the shape, sizing corrects it after the heat of welding moves things around.
We publish three forming technologies: W forming, FFX flexible forming, and linear cage or direct forming. Each changes how the strip is bent and how often you change rolls when switching size. Which one fits depends on your product mix, not on which sounds more modern.
Straightening comes late, after cutting, because a welded tube carries stress from forming and cooling. Rough straightening precedes fine straightening. A tube that is straight out of the mill but banana shaped a week later is usually a stress problem, not a sizing problem.
Published model ranges - we quote only cells the source table attaches clearly to a row | |||||
Model | Round O.D (mm) | Round wall (mm) | Square/rect (mm) | Square wall (mm) | Max speed (m/min) |
|---|---|---|---|---|---|
ERW32 | Φ8–Φ38 | 0.3–2 | 10×10–30×30 | 0.3–1.5 | Max.120/150 |
ERW89 | Φ32–Φ89 | 1.5–4.5 | 25×25–70×70 | 1.5–4 | Max.90 |
ERW254 | Φ114–Φ254 | 3–8 | 90×90–200×200 | 3–6 | Max.50 |
ERW508 | Φ165–Φ508 | 6–16 | 130×130–400×400 | to be confirmed in writing | Max.25 |
ERW630 | Φ325–Φ630 | 6–20 | 300×300–500×500 | to be confirmed in writing | Max.20 |
The model number roughly tracks the largest round tube the line is built around, so ERW89 covers Φ32–Φ89 and ERW254 covers Φ114–Φ254. If your order book sits at Φ60, the ERW254 wastes capital on capacity you will not use.
Speed is the number buyers ask for first and the one we trust least. Max speed in metres per minute is published against some models, but it means nothing until you attach a wall thickness and a strip grade. Model values are for reference and can be customised. Our ERW carbon steel tube mills page holds that table.
Cells that are blank or ambiguous in the source are marked to be confirmed in writing. Some rows share cells because of merged HTML, and guessing there is how a buyer ends up with a line that cannot reach the wall thickness on their order. Send us the tube list and we will map each item in writing.
Our quote form on the product page asks for detailed technical requirements because we design and quote an ERW tube mill against those, not against a model name. The first thing we want is your strip data: grade, width, thickness range, and coil weight. Cold rolled, hot rolled, galvanized, stainless, aluminium and copper all behave differently at the weld. Without the grade, a speed or a wall figure is just a guess.
Next we need the tube list: outside diameter, wall thickness, length, shape, and the standard the buyer will inspect against. We list EN, ASTM, JIS, DIN, GB and API as tube standards a line can be specified against. We are not claiming certification to any of them. Say which one appears on your order, because that decides where inspection equipment sits.
Then we need the plant facts. Available power, cooling water, air supply, bay height and crane capacity all change the layout and the scope. We ask for these in writing early, because they are cheap to confirm and expensive to discover after the foundation is poured. None are numbers we publish about ourselves, so we will not invent them for you.
The first is buying on maximum speed. The second is treating the standards list as a certificate. When a buyer tells us API and expects a stamped approval, we slow the conversation down and talk about what the tube itself has to pass. The standard drives the inspection stations, not a badge on the machine.
The third mistake is skipping the product mix conversation. A line set up for round water pipe and a line set up for square structural tube share a weld station but not much else. Buyers who ask for one universal line end up changing rolls constantly. We would rather scope two honest configurations than one vague one.
We also see buyers forget to ask what is outside the scope. The site lists crane, cooling water, air source, hydraulic and dust removal as part of an integral solution, but each is a decision with a boundary. If you assume everything is in the price and we assume you supply the civils, the argument happens at installation. Put the split in writing.
Customisation is a structural fact of the line, not a marketing word. The published process is for reference, and we say on the page that it can be customised to requirements. You can add online heat treatment, reorder inspection stations, or leave out stations your product never needs.
Component choices are where this gets concrete. We publish a range that includes coil tilters, decoilers, horizontal and vertical accumulators, shear and end welders, forming rolls, impeders, induction coils, scarfing inserts, cold saws, end facing and threading machines, NDT equipment, and automatic packing. Each is a slot, not a default. The ERW tube mill machine overview gives the component level view for comparing two quotes.
We also offer equipment modification and upgrade services, so a line does not have to be frozen on day one. The honest limit is that customisation changes the layout, the foundation and the utilities, which is why we ask for those facts before we quote. Anything we cannot confirm from published data we mark to be confirmed in writing. That is the reason a commissioned line matches the drawing.
An ERW tube mill is a sequence built around one welded joint, and most buying mistakes come from treating it as a single machine with a speed figure. Start with the strip, the tube list and the standard on the order. Let the model table narrow the range, then let your product mix decide the configuration. Ask for every unpublished number in writing.
We are Shijiazhuang FAITH Machinery Co., Ltd., and we build tube mill machines, steel pipe making machines and ERW tube mill lines for buyers specifying against EN, ASTM, JIS, DIN, GB or API. We publish models for reference and design against your technical requirements. Send us your strip data and tube list, and we will come back with a line you can check.
ERW means electric resistance welding. High frequency current heats the strip edges through the skin and proximity effects, then squeeze rolls forge them together with no filler metal. The seam is a forged joint, not added material. Buyers often expect a separate welding wire.
Yes, within a published size range, but not with the same roll setup. Round tube is formed and sized first; square and rectangular sections need their own passes. The model table lists both ranges where the source is clear. Confirm your mix before fixing the tooling, because changeover time is a real cost.
No. We do not publish power in kW, frequency in kHz, efficiency percentages, scrap rates or power consumption. Those depend on strip grade, wall thickness and target speed, and a figure without that context misleads. When a value is not published we write to be confirmed in writing.
No. The site lists those as tube standards a buyer may specify a line against, not certifications we hold. They describe the tube you have to deliver and the acceptance test it must pass. We will not claim a certification we have not published.
Send your strip grade, width and thickness range, coil weight, tube outside diameter, wall thickness, cut length, shape, and the standard on the order. We design and quote against that technical requirement form, not a model name. Unknown figures stay to be confirmed in writing.
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