Brazed Double Wall Zinc-coated Bundy tube used for Compressor
The manufacture of double-wall brazed steel tube uses steel sheets
that have copper coated on both sides, so it has copper on both
inside and outside surfaces as the original surface finish; while
to manufacture the copper-coated single wall ERW steel tubes, steel
sheets shall be coated with copper on the inside surface, rolled
and welded, and then coated with copper on the outside surface
finally.
Double-wall copper brazed steel tubing, also know as Bundy tube or
Bundyweld tube, is the economical alternative to the seamless tube.
It has many of the same qualities as seamless tubing and is
suitable for most high-pressure applications.
High Dimensional Accuracy
Satisfying Mechanical Properties
Clean Inside Surface
We are offering Bundyweld tubes of regular sizes and at the same
time capable of fabricating tubes of customized sizes.
Manufacture Standards
For Bundy tube manufacture, general standards of China, the US,
Japan and other countries are very similar and replaceable and our
tubes meet all of them, except that the material compositions are
slightly different among countries.
China YB/T 4164
US ASTM A254, SAE J527
Japan JASO M101
Russia GOST 11249
India IS 8119
Tube Application
Automotive Hydraulic Brake Lines
Automotive Power Steering Lines
ACR Coolant Transmission Lines
Other Heat Exchanging Equipment
Other Fluid Transmission
Inspection
Eddy Current (Non-Destructive) & Visual Inspection
Flattening & Bending Test
Expansion & Flaring Test
Tension Test
Inside Surface Cleanliness Test
Pressure Proof Test
Brazed Double Wall Tubing
Double-wall tubing is produced by roll forming copper-coated carbon
steel strip into a double wrapped tubular shape as shown in the
cross-sectional diagram. The formed tube is passed through a
controlled atmosphere brazing furnace where it is fused together to
produce a sealed tube. Double-wall tubing is ideally suited for use
in applications that are subject to high levels of vibration and
fatigue, such as household and commercial refrigeration
compressors.
Single-Wall Steel Tubing with the same coating range as double-wall
tubing but with the addition of a nickel-coated internal diameter
to withstand the corrosive environment created by modern-day fuels.
Single & Double Wall Steel Tubing Bundy tubes that can be combined
with an extensive range of corrosion- and abrasion-prevention
coatings such as NyAl (aluminum and polyamide coating), NyZinc
(zinc and polyamide coating), NyGal (Galfan and polyamide coating),
PVF and many others. These tubes can also be provided with a
polypropylene jacket to provide outstanding abrasion resistance.
Single and Double Wall Bundy Tubes
| Type | Double Wall (TDW) | Single Wall (TSW) |
| Welding Technique | Copper brazing | High-frequency ERW |
| Resizing Method | Cold drawn | Cold drawn |
| Seam | 720 Degree seamless | Straight-line seamed |
| Dimensional Accuracy | High | High |
| Strength | Mostly made hard | Can be soft or hard |
| Inside Cleanliness | Good | Poor |
| Vibration Resistance | Strong | Poor |
| Safety against Pressure | High | Low |
| Application | Automobile brake lines, fuel lines, transmission cooler lines,
power steering lines; certain hydraulic pipes, etc; | AC, refrigeration, heat exchangers, automobile fuel lines;
compressors, etc; |
| Original Surface | Copper | None (steel) |
| Surface Coating | Copper Zinc GALFAN |
Copper Zinc |
