Zinc Coated Tube – Bundy Tube Manufacturer in China | PIPECW

A zinc coated tube gives thin steel lines the corrosion protection they need without adding bulk. In brake systems, air conditioners and refrigerators, that protection matters. Buyers also need tight tolerance, clean inside walls and steady quality from one batch to the next.
PIPECW is a Bundy tube manufacturer in China. We supply zinc coated Bundy tube made with precision welding and strict dimensional control. The tube has a sturdy structure and tight tolerance, and it suits hydraulic brake systems, AC units, refrigerators, heat exchangers and compressors.
This guide explains what a zinc coated tube is, how it differs from copper plated tube, how to read the specifications, and what to check before you order. Importers, distributors, OEM buyers and procurement teams in North America, Europe, the Middle East, Asia-Pacific, South America and Africa can use it as a practical checklist.

What Is a Zinc Coated Tube?

 
A zinc coated tube is a steel tube with a layer of zinc on its surface. The zinc acts as a barrier against moisture and oxygen. It also protects the steel at small scratches, because zinc corrodes first. Buyers may also call it a zinc plated tube or a galvanized steel tube, depending on the coating method.
In precision fluid lines, the coating must be thin, even and clean. A rough or uneven coat can cause problems at fittings, during bending and inside the system. That is why small-diameter tube needs closer control than general structural pipe.

Why Buyers Choose Zinc Coating

  • Corrosion protection for tube exposed to humidity, road splash or condensation
  • A clear surface finish that is easy to identify during inspection and assembly
  • A practical coating for tube that is cut, bent and connected into assemblies

What Is a Zinc Coated Bundy Tube and How Is It Made?

Bundy tube is a precision steel tube made from low-carbon steel strip. The strip is formed into a tube, and the seam is joined to create a strong, leak-tight line. The classic design is double-wall, which gives high rigidity and low volume expansion under pressure. Bundy tube has long been used for automotive brake lines and refrigeration systems.
Our zinc coated Bundy tube belongs to our Bundy Tube range. Together with copper coated tube and plain welded tube, it covers the main surface options for precision fluid lines.

Main Production Steps

1. Strip preparation: low-carbon steel strip is selected and prepared for forming.
2. Forming and precision welding: the strip is formed into a tube and welded under tight process control.
3. Dimensional control: outer diameter and wall thickness are held to a tolerance of ±0.05 mm.
4. Zinc coating: tube below 8 mm OD uses hot-dip galvanizing. Tube from 8 mm OD uses electro zinc coating.
5. Cleaning and testing: inside cleanliness and airtightness are checked before packing.
Exact steps can vary by size and order requirements.

Zinc Coated Tube vs Copper Plated Bundy Tube: What’s the Difference?

 
Both tubes share the same Bundy tube structure, size range and tolerance on our website. The main difference is the surface coating. Buyers choose between them based on the working environment, the connection method and their own specification.

Item	Zinc Coated Tube	Copper Coated Tube
Surface coating	Zinc (hot-dip below 8 mm OD, electro zinc from 8 mm OD)	Copper
Main purpose	Corrosion protection on the outer surface	Combines Bundy tube strength with copper’s conductivity and corrosion resistance
Typical uses	Hydraulic brake systems, AC, refrigerators, heat exchangers, compressors	AC, refrigerators, hydraulic systems, automotive components, industrial fluid lines
Listed OD range	4–8 mm	4–8 mm
OD and WT tolerance	±0.05 mm	±0.05 mm

If your project calls for a copper finish, see our Copper Coated Tube page. If you are not sure which finish suits your assembly, send us your drawing and working conditions. Our team can help you compare options before you order.

Zinc Coated Tube Specifications: OD, Wall Thickness and Tolerance

Check the size range first. Our listed zinc coated tube sizes cover the small-diameter lines used in brake and refrigeration systems.

Outer Diameter (OD, mm)	Wall Thickness (WT, mm)
4	0.5
4.76	0.6
4.76	0.65
6	0.6
6	0.65
8	0.7

Tolerance on both outer diameter and wall thickness is +0.05 mm and -0.05 mm. This tolerance helps the tube fit connectors and bending tools consistently from batch to batch. If you need a size that is not listed, send us your drawing and we will check what is possible.

What to Confirm Before You Order

  • Outer diameter and wall thickness
  • Required cut length
  • Surface treatment: zinc coated or copper coated
  • Order quantity and delivery schedule
  • End use and any customer standard that applies

Hot-Dip Galvanized vs Electro Zinc Coated Tube: Which One Do You Need?

We use two zinc coating methods, and the method follows the tube size. Tube below 8 mm OD uses hot-dip galvanizing. Tube at 8 mm OD and above uses electro zinc coating, also called electro galvanizing.

Item	Hot-Dip Galvanized	Electro Zinc Coated
Our size rule	OD below 8 mm	OD 8 mm and above
How it works	Tube passes through molten zinc	Zinc is deposited from a solution using electric current
General character	Zinc layer bonds to the steel surface	Thin, smooth and even zinc layer

Most buyers do not need to choose the method, because we apply the one that matches the tube size. If your customer specification sets a coating thickness or a salt spray target, tell us at the inquiry stage. We will confirm what is possible before you place the order.

Mechanical Properties and Chemical Composition of Our Zinc Coated Tube

 
The steel under the coating decides how the tube bends, flares and holds pressure. These are the values listed for our tube.

Property	Value
Tensile strength, Rm	≥ 270 N/mm²
Yield strength, ReL	≥ 180 N/mm²
Elongation, A	≥ 14 %
Carbon (C)	≤ 0.11 %
Manganese (Mn)	≤ 0.4 %
Sulfur (S)	≤ 0.03 %
Phosphorus (P)	≤ 0.03 %

The carbon content is low. Low-carbon steel forms easily, which helps in bending operations. The elongation value shows how far the tube can deform before it breaks. Before a large order, test a sample in your own bending and connection process.

Quality Control: Airtight Test, Cleanliness and Dimensional Check

In fluid lines, small defects cause big problems. We focus on three checks that matter most to buyers.

Dimensional Check

Outer diameter and wall thickness are held to ±0.05 mm. Tight control reduces fitting problems on your assembly line.

Airtight Test

The tube is tested with nitrogen at 1.6 MPa, and the result must show no leaking. This test checks that the tube holds pressure without leakage.

Inside Surface Cleanliness

Soluble and insoluble residue on the inside surface stays below 50 mg/m². Clean inner walls help protect valves, compressors and brake components from contamination.
Tell us which inspection records you need with your order, and we will confirm what we can provide.

Key Advantages of Zinc Coated Bundy Tube

  • Tight tolerance: ±0.05 mm on outer diameter and wall thickness supports stable fitting and bending.
  • Sturdy structure: Bundy tube construction gives rigidity for pressure lines.
  • Corrosion protection: the zinc layer protects the outer surface of the steel.
  • Clean interior: residue stays below 50 mg/m².
  • Leak-tested: airtight tested with nitrogen at 1.6 MPa.
  • Small sizes: OD 4–8 mm suits compact assemblies.
  • Related options: copper coated tube and plain welded tube come from the same Bundy tube range.

Zinc Coated Tube for Hydraulic Brake Systems

Brake lines carry fluid under pressure, so they need a strong wall, accurate dimensions and a clean inside surface. Bundy tube is widely used in hydraulic brake lines for this reason. Our zinc coated tube supports precision fluid transmission in hydraulic brake systems.
Typical buyers include brake line assemblers, auto parts makers and distributors who supply the aftermarket. If you also source other tube for vehicle systems, browse our Automotive Steel Tube range.

Points to Confirm for Brake Line Orders

  • Outer diameter, wall thickness and cut length
  • Bending and flaring method used on your line
  • Any standard or approval your market requires

Zinc Coated Tube for Air Conditioners, Refrigerators and Compressors

Air conditioning and refrigeration lines need leak-free joints and clean inner walls. Our tube is airtight tested at 1.6 MPa with nitrogen, and inside residue stays below 50 mg/m². The zinc coating adds protection against moisture and condensation on the outside of the tube.
Typical uses include AC units, refrigerator tubing and compressor connection lines. Before ordering, confirm the refrigerant type, operating pressure and connection method with your engineer. Then send us the tube size and quantity for a quotation.

Zinc Coated Tube for Heat Exchangers and Precision Fluid Transmission

Heat exchangers use many small tubes, so size consistency matters. A tight tolerance of ±0.05 mm helps tubes fit assembly tools and joints in a repeatable way. Thin walls from 0.5 mm to 0.65 mm also suit compact designs.
The same features serve other precision fluid lines in industrial equipment. If your application is not listed here, describe the medium, pressure and temperature range. We will tell you whether our zinc coated Bundy tube is a good match or whether another coating suits you better.

Why Choose PIPECW as Your Zinc Coated Tube Supplier in China?

Zhangjiagang Chewit International Co., Ltd. operates the PIPECW brand from Zhangjiagang, Jiangsu Province. The company supplies precision steel tubes, forging parts and aluminum products, and it has more than a decade of history in steel pipe. Our website shows company certificates, and you can ask for copies that fit your market requirements.
For buyers, the key point is a supplier that answers technical questions clearly. We list our sizes, tolerances, test values and composition openly, so you can compare them with your own specification.

How to Choose a Zinc Coated Tube Supplier

  • Ask for size, tolerance and test data in writing.
  • Confirm which coating method applies to each tube size.
  • Request samples and test them in your own process.
  • Check inside cleanliness and leak test values, not only outside appearance.
  • Compare how fast and how clearly the supplier replies.
  • Confirm packaging, documents and shipping terms before payment.

How to Order Zinc Coated Tube: MOQ, Samples and Lead Time

 
Order terms depend on size, coating and quantity. We confirm MOQ, sample arrangements and lead time in each quotation, so you get figures that match your real order. To receive an accurate quote quickly, send us this information:
  • Outer diameter and wall thickness
  • Coating type: zinc coated or copper coated
  • Cut length and quantity
  • Application, such as brake line, AC, refrigerator or heat exchanger
  • Drawing or customer standard, if available
  • Packaging needs and destination port
If you need samples for testing, mention it in your inquiry. We will confirm the sample arrangement together with your quotation. You can reach us at sale@chewit.cn or on WhatsApp at +86 18962244644.

Packaging and Export Shipping for Zinc Coated Tube

Zinc coated tube must arrive clean, dry and undamaged. We agree packaging and shipping terms for each order. These are the main points to settle before shipment:
  • Bundling and protection against moisture and impact
  • Labels showing size, batch and coating type
  • Carton, pallet or case requirements from your market
  • Trade terms, such as FOB or CIF, and the port of loading
  • Documents your customs office needs for clearance
Tell us your destination country and your preferred terms. We will plan the shipment to match.

Zinc Coated Tube FAQ

1. What is a zinc coated tube?

A zinc coated tube is a steel tube with a zinc layer on its surface for corrosion protection. Our version is a zinc coated Bundy tube made with precision welding and strict dimensional control.

2. What sizes of zinc coated tube are available?

Our listed sizes are OD 4 mm × 0.5 mm, 4.76 mm × 0.6 mm and 0.65 mm, 6 mm × 0.6 mm and 0.65 mm, and 8 mm × 0.6 mm. Contact us if you need another size.

3. Does PIPECW use hot-dip or electro zinc coating?

Both. Tube below 8 mm OD uses hot-dip galvanizing. Tube from 8 mm OD uses electro zinc coating.

4. Can zinc coated tube be used for brake lines?

Yes. Hydraulic brake systems are one of its listed applications, along with AC, refrigerators, heat exchangers and compressors. Please confirm any standard your market requires when you send your inquiry.

5. What is the tolerance of your zinc coated tube?

The tolerance is +0.05 mm and -0.05 mm on both outer diameter and wall thickness.

6. How can I get a quotation or samples?

Send your size, quantity, coating type and application through our website or by email. We will reply with a quotation and confirm MOQ, sample arrangements and lead time for your order.

Get a Quotation for Zinc Coated Tube

A reliable zinc coated tube combines tight tolerance, a clean inside surface, a tested seal and the right coating for the job. PIPECW supplies zinc coated Bundy tube in OD 4–8 mm for hydraulic brake systems, air conditioners, refrigerators, heat exchangers and compressors.
Ready to talk about your project? Visit our CONTACT page, or email sale@chewit.cn with your size, quantity and application. Our team can help with product details, quotations, samples and technical questions.