Welding Steel Tube | ERW Carbon Steel Tube Manufacturer China

Buyers who import tube in volume need three things: stable quality, clear specifications and a supplier who answers questions fast. Welding steel tube meets many of these needs at a sensible price, which is why importers, distributors, OEM buyers and project contractors use it every day.
This guide explains what welding steel tube is, how ERW production works, which sizes and grades are available, and where the product performs best. It also compares ERW and seamless tube and lists what to include in your inquiry. Zhangjiagang Chewit International Co., Ltd. wrote it to help you compare suppliers and prepare a clear request for quotation.

What Is Welding Steel Tube? ERW Process Explained

 
Welding steel tube is made from flat steel strip. A tube mill rolls the strip into a round shape, and electric resistance welding (ERW) joins the two edges. The process uses heat from electric current and pressure, so it needs no filler metal. The result is a straight, uniform tube with a smooth surface and accurate dimensions.
Zhangjiagang Chewit International Co., Ltd. produces ERW carbon steel tube for international buyers. Our ERW tube offers high weld strength, precise dimensions and a smooth surface. It performs steadily and costs less than many other tube types, so importers, distributors and factory buyers use it across many industries.
Buyers choose this product for several practical reasons:
  • Consistent wall thickness and outer diameter from coil to coil
  • Smooth surface that suits bending, cutting, painting and plating
  • Cost-effective supply for medium and high volume orders
  • Wide choice of sizes, steel grades and finishes
  • Good fit for both structural and light fluid applications

Welding Steel Tube Specifications: OD 6–150mm, Length 3–12m

The table below shows the standard range of our welding steel tube. If your project needs a different size, we can discuss custom options.

Parameter	Details
Product type	Welded carbon steel tube
Manufacturing process	ERW (Electric Resistance Welded)
Material grade	Q195, Q235, Q345, ST37, ST52, or as required
Outer diameter (OD)	6 mm – 150 mm (custom sizes available)
Wall thickness	0.1 mm – 5 mm
Length	3 m – 12 m, or as requested
Tolerance class	EN 10305-2 / GB/T 13793, or custom
Surface finish	Annealed, zinc-plated

Other specifications are available on request. Not every OD and wall thickness combination suits every mill setup, so send your drawing or size list early. Our team will confirm what we can supply and suggest the closest practical option if needed.

Common Material Grades: Q195, Q235, Q345, ST37, ST52

Grade selection affects strength, formability and cost. Here is a simple guide to the grades we list for our welding steel tube:
  • Q195: low-carbon grade with easy forming. It suits general use and light structural parts.
  • Q235: a common general-purpose grade for frames, fences and machinery parts.
  • Q345: a higher-strength grade for parts that carry more load.
  • ST37: a European-style designation, roughly in the S235 class.
  • ST52: a higher-strength European-style designation, roughly in the S355 class.
We can also discuss other carbon steel grades, such as Q215, Q235B, 10# and 20#. Please confirm exact equivalents against the standard your market requires. If your project needs alloy or corrosion-resistant material, we also supply alloy steel tube and stainless steel tube. Please tell us the application, and we will help you choose a suitable grade.

ERW Carbon Steel Tube Manufacturing Process

A typical ERW production line follows these steps:
1. Material selection: the mill selects carbon steel strip in the required grade and thickness.
2. Slitting and uncoiling: the strip is cut to the correct width and fed into the tube mill.
3. Forming: rollers shape the strip gradually into a round tube.
4. ERW welding: electric resistance heating and pressure join the seam.
5. Sizing and straightening: the tube passes through rollers to reach the target OD and straightness.
6. Heat treatment or finishing: the tube may be annealed or zinc-plated, depending on the order.
7. Cutting and inspection: the tube is cut to length and checked before packing.

Quality checks buyers should request

Quality should never rely on a verbal promise. Before you place an order, ask your supplier to confirm:
  • Material test certificate for the steel grade
  • Outer diameter, wall thickness and length inspection
  • Weld seam condition and surface appearance
  • Straightness and end finish
  • Any third-party inspection you need before shipment
Clear inspection requirements in the purchase order protect both sides and reduce disputes later.

Welding Steel Tube Dimensional Tolerance (EN 10305-2 / GB/T 13793)

Tolerance matters most for OEM buyers who cut, bend or assemble tube in volume. Tight dimensions reduce scrap and keep assembly lines running. We supply tube to EN 10305-2 or GB/T 13793, or to a custom tolerance agreed with the buyer.
The table gives an example based on EN 10305-2:

OD (mm)	Tolerance (mm)	Wall thickness (mm)	Tolerance (mm)
10	± 0.05	1.0	± 0.05
16	± 0.05	1.5	± 0.05
20	± 0.05	2.0	± 0.05
25	± 0.05	2.5	± 0.05
32	± 0.05	3.0	± 0.05
40	± 0.05	3.5	± 0.05
50	± 0.08	4.0	± 0.05

Final tolerance depends on the standard, size and finish of your order. Please state your required standard in the inquiry so we can quote correctly. For projects with very tight tolerances, our Cold Drawn Steel Tube range may also be worth reviewing.

Surface Finish Options: Annealed and Zinc-Plated

 
Surface finish changes how the tube performs in storage, processing and service. We offer two finishes for this product:
  • Annealed: heat treatment relieves stress and improves formability. It helps when you bend, flare or form the tube.
  • Zinc-plated: a zinc layer adds corrosion protection for storage, transport and outdoor or humid use.
If you need a heavier protective coating, visit our Galvanized Steel Tube page to compare options. Tell us how the tube will be used and stored, and we will recommend the most suitable finish.

Welding Steel Tube Applications by Industry

Our welding steel tube serves fluid transmission, construction, automotive, machinery manufacturing and agricultural equipment. It carries water, natural gas and oil in light-duty lines. It also forms scaffolding, guardrails, exhaust pipes and frame parts.
These are the main industries our buyers work in:
  • Automotive: exhaust systems, chassis components, seat frames and structural parts
  • Furniture: chair frames, tables, shelving and display racks
  • HVAC: air conditioning lines, heating system pipes and ventilation ducts
  • General engineering: roll cages, conveyor rollers, fencing and sign posts
  • Hydraulic (low to medium pressure): return lines, drain lines and non-critical fluid transfer
The next three sections look at the most common uses in more detail.

Welded Steel Tube for Automotive: Exhaust Pipes and Frame Components

Automotive parts need stable size and a clean surface. Exhaust pipes, chassis parts and seat frames are cut, bent and welded in large numbers. Any variation in OD or wall thickness slows production.
When you source tube for automotive parts, check these points:
  • OD and wall thickness tolerance for your bending or fitting process
  • Steel grade and delivery condition (for example, annealed for easier forming)
  • Surface cleanliness before coating or plating
  • Length tolerance and end quality for automatic cutting lines
Share your drawing, annual volume and bending radius. These details help us judge whether standard ERW carbon steel tube fits your part.

Welding Steel Tube for Construction: Scaffolding and Guardrails

Construction buyers use welding steel tube for scaffolding, guardrails, fencing and sign posts. These products need reliable strength, straight length and a surface that resists corrosion outdoors.
For these projects, buyers usually focus on three things. First, they choose a grade such as Q235 or Q345 that matches the load requirement. Second, they select zinc-plated tube when the product will stand outside. Third, they specify standard lengths, often between 3 m and 12 m, to reduce cutting waste on site.
Contractors and distributors in markets such as the Middle East, Southeast Asia, Africa and South America often order mixed sizes in one shipment. Send us your full size list, and we will quote it together.

Welding Steel Tube for Furniture, HVAC and Machinery

 

Furniture and display products

Chair frames, tables, shelving and display racks need a smooth surface and consistent diameter. Good surface quality supports painting, powder coating and plating. Small and medium ODs are most common in this field.

HVAC systems

HVAC makers use the tube in air conditioning lines, heating system pipes and ventilation ducts. Clean ends and stable dimensions help with flaring, joining and assembly.

Machinery and hydraulic return lines

Machine builders use the tube for roll cages, conveyor rollers and equipment frames. It also works in low to medium pressure hydraulic return lines, drain lines and other non-critical fluid transfer. For demanding hydraulic circuits, review our Hydraulic Pipe/Tube range instead, which is better matched to higher pressure needs.

ERW Welded Tube vs Seamless Steel Tube: Which Should You Choose?

This is one of the most common questions from importers. Both products have a place. The right choice depends on pressure, budget and how the tube will be used.

Factor	ERW welded tube	Seamless steel tube
Production	Formed from strip and welded with ERW	Made without a weld seam
Cost	Usually lower, good for volume	Usually higher
Dimensional consistency	Stable OD and wall thickness	Good, but wall can vary more by process
Surface	Smooth and uniform	Depends on finishing method
Pressure use	Light to medium pressure	Better for high pressure and critical service
Typical uses	Automotive, furniture, HVAC, construction, machinery	Hydraulic, boiler, oil and gas, high-pressure lines

Choose ERW welded tube when you need good dimensional consistency, a smooth surface and competitive pricing for volume orders. It suits furniture, automotive parts, construction, HVAC and general machinery.
Choose seamless steel tube or seamless steel pipe when the application involves high pressure, high temperature or safety-critical service. Zhangjiagang Chewit also supplies precision seamless products, so you can compare both options with one supplier. If you are unsure, tell us the working pressure and medium, and we will give an honest recommendation.

Custom Sizes and Lengths Available on Request

Many buyers need sizes that are not in a standard catalogue. We offer custom sizes and lengths on request. To receive an accurate quotation quickly, please include:
  • Outer diameter and wall thickness
  • Required length and length tolerance
  • Steel grade and applicable standard
  • Surface finish (annealed or zinc-plated)
  • Order quantity and target delivery port
  • Application and any special requirement, such as end finish or marking
A complete inquiry saves time. It also helps us avoid wrong assumptions about your welding steel tube order.

Why Choose Us as Your Welding Steel Tube Manufacturer in China

 
Zhangjiagang Chewit International Co., Ltd. is a professional supplier of precision steel tube, forging products and aluminum products. Our office and factory base is in Jingang Town, Zhangjiagang City, Jiangsu Province, China.
Besides welding steel tube, our product range includes seamless steel tube, stainless steel pipe, stainless steel tube, hydraulic steel tube, CNG tube and alloy steel tube. We also supply aluminum tube, aluminum telescopic pole, aluminum tent pole, open die forging parts, closed die forging parts and forging small parts. This range lets distributors and project buyers combine several products in one sourcing plan.
Use this checklist when you compare any welding steel tube manufacturer:
  • Ask for a clear specification sheet and written confirmation of grade, size and standard
  • Request copies of the certificates relevant to your project. You can view the certificates displayed on our website and ask us for details.
  • Confirm inspection methods and what documents come with each shipment
  • Check how the supplier handles packing, loading and export documents
  • Judge response speed and technical clarity before you order
A reliable supplier answers technical questions directly and puts the answers in writing.

Welding Steel Tube FAQ: MOQ, Lead Time, Samples and Packing

What is welding steel tube used for?
It is used in automotive parts, scaffolding, guardrails, furniture frames, HVAC lines, conveyor rollers, fencing and low to medium pressure fluid lines. The right size and grade depend on your application.
What sizes can you supply?
Our standard range covers an outer diameter of 6 mm to 150 mm, wall thickness of 0.1 mm to 5 mm, and length of 3 m to 12 m. Custom sizes are available on request.
What is the MOQ and lead time?
MOQ and lead time depend on size, grade, finish and order quantity. Send us your specification, and we will confirm both in your quotation.
Can I get a sample before placing a bulk order?
Please contact us with your required size and grade to discuss sample options. We will explain what we can arrange for your item.
How do you pack welding steel tube for export?
Steel tube is commonly packed in bundles with protection for the surface and ends, then loaded in containers or other agreed transport. Packing can be adjusted to your market and handling needs. Please share your requirements when you inquire.
Which standards and grades do you offer?
We offer tube to EN 10305-2 and GB/T 13793 or custom tolerance. Common grades are Q195, Q235, Q345, ST37 and ST52, and other grades can be discussed as required.

Get a Welding Steel Tube Quote from Zhangjiagang Chewit

Good welding steel tube supply starts with clear specifications and an open supplier relationship. Know your size, grade, finish and standard, then compare suppliers on technical clarity and service. This approach protects quality and reduces the cost of mistakes.
Zhangjiagang Chewit International Co., Ltd. is ready to support your ERW carbon steel tube project, from size selection to export shipment. Visit our CONTACT page, or send your drawing and size list to sale@chewit.cn. You can also reach us on WhatsApp at +86 18962244644. Tell us what you need for product details, quotation, customization, samples or technical support, and our team will reply with practical advice.