Copper Coated Tube – Bundy Steel Tube Manufacturer | Chewit

Buyers who search for copper coated tube often find two different products. One is plastic-coated copper pipe for plumbing. The other is copper coated steel tube for precision fluid lines. This article covers the second one: a low-carbon steel Bundy tube with a copper coating, used in cooling, hydraulic and automotive systems.
If you import, distribute or build equipment that needs small-diameter steel tube, this guide helps you compare options before you send an inquiry. It covers sizes, tolerance, mechanical data, testing, surface options, customization and supplier checks. All technical data comes from the product page for our copper coated tube at Chewit.

What Is Copper Coated Tube? (Copper Coated Bundy Tube Explained)

 
A copper coated tube is a steel tube with a thin layer of copper on its surface. The steel base gives strength. The copper layer adds corrosion resistance and a smooth surface. Buyers also call it copper coated steel tube or copper plated steel tube.
In our range, it is a copper coated Bundy tube. A Bundy Tube is a small-diameter precision tube made from rolled steel strip. Industries use it for refrigerant, fuel and hydraulic lines, where the tube must hold its shape, resist vibration and stay leak-free.
It is not solid copper pipe, and it is not PVC-coated copper tube for water systems. Knowing the difference helps you write a clear inquiry and avoid wrong quotations.

Copper Coated Tube Specifications: OD 4–10mm, WT 0.5–0.65mm

Our copper coated tube is listed in the sizes below. OD means outer diameter. WT means wall thickness.

Available Sizes

  • OD 4 mm × WT 0.5 mm
  • OD 4.76 mm × WT 0.6 mm and 0.65 mm
  • OD 6 mm × WT 0.6 mm and 0.65 mm
  • OD 8 mm × WT 0.6 mm

Key Technical Data

  • Outer diameter tolerance: +0.05 mm / -0.05 mm
  • Wall thickness tolerance: +0.05 mm / -0.05 mm
  • Airtight test: 1.6 MPa nitrogen, no leakage
  • Inside surface cleanliness (soluble and insoluble residue): below 50 mg/m²
  • Tensile strength Rm: ≥270 N/mm²; yield strength ReL: ≥180 N/mm²; elongation A: ≥14%
  • Chemical composition: C ≤0.11%, Mn ≤0.4%, S ≤0.03%, P ≤0.03%
The sections below explain what each number means for your project. Need a different size or length? Send your drawing and our team will check if we can make it.

Key Features of Our Copper Coated Bundy Steel Tube

Our copper coated Bundy tube is built for precision systems where small errors cause leaks or assembly problems. Main features include:
  • Steel strength with a copper-coated surface
  • Tight tolerance of ±0.05 mm on outer diameter and wall thickness
  • Smooth surface and precise dimensions for stable connections
  •Clean inside surface, with residue below 50 mg/m²
  •Leak testing at 1.6 MPa with nitrogen
  •Compact sizes from OD 4 mm to OD 8 mm for tight installation space

Why Choose Copper Coated Tube? Strength Plus Corrosion Resistance

Buyers choose copper coated tube when they need more strength than copper tube and better surface protection than bare steel.

Strength from the Steel Base

Low-carbon steel gives a tensile strength of at least 270 N/mm² and a yield strength of at least 180 N/mm². The tube handles pressure and vibration in compressors, hydraulic circuits and vehicle systems.

Corrosion Resistance from the Copper Coating

The copper layer protects the outer surface from moisture and many fluids. This supports a longer service life, although actual life depends on the operating environment.

Cost Control for Volume Orders

Steel usually costs less than solid copper, so a copper coated tube can lower material cost in volume projects. Final price depends on size, quantity and coating requirements.

Copper Coated Tube Applications: AC, Refrigerators, Hydraulic and Automotive

Air Conditioning and Refrigerators

Small-diameter tube carries refrigerant between system parts. A clean inside surface and a leak-free wall matter most here. Our tube is tested at 1.6 MPa with nitrogen, and the inside residue stays below 50 mg/m².

Hydraulic Systems

Precise outer diameter and wall thickness help fittings seal well and keep fluid lines stable. This is important for compact hydraulic circuits.

Automotive Components

Bundy-type tube is common in automotive fluid lines. If you source for vehicle programs, browse our Automotive Steel Tube range for related products.

Industrial Fluid Lines

Machines and industrial equipment use this tube for compact fluid transmission lines that need accurate size and dependable strength.

Single Wall vs Double Wall Copper Coated Tube

 
Wall type affects pressure strength, flexibility and cost. Here is how the two types differ in general:
  • Double wall: the steel strip is rolled into two layers that bond into one tube. This design gives higher burst strength and better vibration resistance. It is the traditional Bundy tube design for refrigeration and automotive lines.
  • Single wall: the tube has one layer. It is simpler and lighter, and suits lines with lower pressure demand.
Our Bundy Tube category lists double wall steel tubes. For welded tube without a second layer, see our Plain Welded Tube page. Tell us your working pressure and bending needs, and we will confirm which wall type we can supply.

Mechanical Properties: Tensile ≥325 N/mm², Yield ≥208 N/mm², Elongation ≥42%

  • Tensile strength Rm ≥325 N/mm²
  • Yield strength ReL ≥208N/mm²
  • Elongation A ≥42%
Tensile strength shows how much load the tube carries before it breaks. Yield strength shows when permanent deformation starts. Elongation shows how well the tube bends or flares without cracking.
An elongation of at least 42% supports normal bending and end forming. If your process uses tight-radius bends or heavy flaring, send us your forming method so we can review it.

Chemical Composition of Low-Carbon Steel Bundy Tube

  • Carbon (C): ≤0.11%
  • Manganese (Mn): ≤0.4%
  • Sulfur (S): ≤0.03%
  • Phosphorus (P): ≤0.03%
Low carbon content improves formability, so the tube bends and flares more easily. Low sulfur and phosphorus reduce the risk of cracking during forming. Ask every supplier to confirm chemical results in writing before you place a bulk order.

Dimensional Tolerance: ±0.05mm on OD and Wall Thickness

Our copper coated tube holds a tolerance of +0.05 mm / -0.05 mm on both outer diameter and wall thickness. Tight tolerance matters for three reasons:
  • Fittings and connectors seal better when the outer diameter is stable.
  • Automatic assembly lines run with fewer stops when tube size is consistent.
  • Pressure performance stays predictable when wall thickness is controlled.
On a 0.6 mm wall, ±0.05 mm is about 8%. Check the tolerance on your drawing and agree with your supplier on how it is measured.

Quality Control: 1.6 MPa Airtight Test and Inside Surface Cleanliness

Airtight Test

Each tube specification lists a seal airtight test of 1.6 MPa with nitrogen, without leaking. This test checks the wall and the joint for leaks before delivery.

Inside Surface Cleanliness

Soluble and insoluble residue inside the tube stays below 50 mg/m². Residue can damage compressors, valves and hydraulic parts, so a clean bore protects your final product.

Inspection and Certification

Our inspection team checks product quality before delivery, using a full set of inspection equipment. Our About Us page lists ISO 9001, IATF 16949 and PED certificates for the company. If your project needs specific test reports or documents, tell us early so we can confirm what we can provide.

How Copper Coated Bundy Tube Is Manufactured

Bundy tube is generally made in the following steps. Exact steps depend on tube type and order.
1. Prepare low-carbon steel strip with a copper coating.
2. Form the strip into a tube. For double wall tube, roll the strip into two layers.
3. Pass the tube through a furnace so the layers join.
4. Size the tube to the final outer diameter and wall thickness.
5. Clean the inside surface to meet the cleanliness limit.
6. Test and inspect the tube before packing.
Ask our team to explain the production route for your size and wall type.

Copper Coated Tube vs Copper Tube vs Galvanized Tube

Buyers often compare three options. The table below shows the main differences in general terms.

Feature	Copper Coated Tube (Bundy Steel Tube)	Solid Copper Tube	Galvanized (Zinc Coated) Tube
Base material	Low-carbon steel with copper coating	Pure copper or copper alloy	Low-carbon steel with zinc coating
Strength	High, from the steel base	Lower, softer metal	High, from the steel base
Corrosion protection	Copper coating protects the surface	Very good, copper throughout the wall	Zinc coating protects the surface
Typical use	AC, refrigerators, hydraulic and automotive lines	Plumbing, HVAC, heat transfer	Automotive and industrial fluid lines
Cost level	Usually lower than solid copper	Higher, follows copper price	Depends on size and coating
Best when	You need strength and a copper surface	You need full copper properties	You need zinc protection at a practical cost

 
To choose the right type, think about your main need:
  • Choose copper coated tube when you need steel strength with a copper surface at a practical cost.
  • Choose solid copper tube when you need full copper properties, such as heat transfer through the whole wall.
  • Choose galvanized tube when zinc protection fits your system. See our Zinc Coated Tube page for details.

Custom Sizes, Surface Treatment and Packing Options

Custom Sizes and Lengths

Our technical team supports customers with their own designs. If you need a size or length outside the list above, send us your drawing and we will check feasibility.

Surface Treatment

Our product page lists copper-plated and zinc-coated surface options. If your application needs another finish, ask us before you order.

Packing and Export

Packing method, bundle length, labeling and shipping documents should be agreed before the order. Tell us your destination port and handling needs, and we will suggest a packing plan.

What to Include in Your Inquiry

  • Outer diameter and wall thickness
  • Tube length and order quantity
  • Single wall or double wall requirement
  • Surface treatment
  • Application and working pressure
  • Drawing, standard or test requirements
  • Destination port

Copper Coated Tube Manufacturer in China: About Chewit

 
Zhangjiagang Chewit International Co., Ltd. supplies precision steel tubes, forging and aluminum products from Jingang Town, Zhangjiagang, Jiangsu, China. According to our About Us page, the company was founded in 2010, covers 10,000 square meters and has around 120 employees.
Our steel tubes serve the automotive, hydraulic, mechanical and precision-device fields. We work with importers, distributors, OEM buyers and project contractors, and we are ready to support buyers in North America, Europe, the Middle East, Asia-Pacific, South America and Africa.

How to Check a Tube Supplier Before You Order

  • Confirm the factory address, company name and certificates match.
  • Compare tolerance, test data and cleanliness limits, not only price.
  • Ask for samples or test results for your size.
  • Agree on packing, lead time and documents in writing.
  • Check how fast and how clearly the supplier answers technical questions.

Frequently Asked Questions About Copper Coated Tube

What is copper coated tube used for?

Copper coated tube is used in air conditioning, refrigerators, hydraulic systems, automotive components and industrial fluid lines. It suits compact lines that need steel strength and a corrosion-resistant surface.

What sizes of copper coated tube are available?

Listed sizes run from OD 4 mm to OD 8 mm, with wall thickness from 0.5 mm to 0.65 mm. Contact us if you need another size.

What airtight test pressure does the tube meet?

The tube specification lists a seal airtight test of 1.6 MPa with nitrogen, without leaking.

Is copper coated tube the same as copper tube?

No. Copper coated tube has a steel base with a copper layer on the surface. Solid copper tube is copper through the whole wall. Copper coated tube offers higher strength, and solid copper tube offers full copper properties.

Can you customize copper coated tube?

Yes, we can review custom requests. Send your drawing, size, length and application, and our team will confirm what is possible.

How do I request a quotation or sample?

Send your size, quantity, wall type, surface requirement and destination port by email or WhatsApp. Our team will reply with details, and we can discuss sample options for your project.

Conclusion

Copper coated tube combines the strength of low-carbon steel with a copper-coated surface. With sizes from OD 4 mm to 8 mm, a tolerance of ±0.05 mm, a 1.6 MPa airtight test and a clean inside surface, it fits AC, refrigerator, hydraulic and automotive lines.
If you want product details, a quotation, customization or technical support for copper coated tube, please Contact our team. You can also write to sale@chewit.cn or message us on WhatsApp at +86 18962244644.