Bundy tube, sometimes called
Bundy pipe, is type of double-walled
low-carbon steel tube manufactured by rolling a
copper-coated steel strip through 720 degrees and resistance
brazing the overlapped seam in a process called
Bundywelding. Some key sources are Shelley Automation ltd in the UK and
SVS Refcomp Pvt Ltd in India
History
It may be
zinc or
terne coated for
corrosion protection. It is used in automotive
hydraulic brakes in cars manufactured in the US since the 1930s.
The Bundy Tubing Company, started in the US, was bought in the 1980s by what is now the British company TI Fluid system
.
Kunifer pipe
A 1969 study by the Society of Automotive Engineers (SAE) recommended the replacement of Bundy tube with 90-10 copper-nickel alloy UNS C70600 (Kunifer pipe) because of corrosion concerns.
[A.G. Imgram and D.K. Miner, Paper 690530, Mid-Year Meeting, May 1969] Kunifer pipe has since been adopted by European automakers
Volvo, Rolls-Royce,
Lotus Cars,
Aston-Martin,
Porsche, and
Audi.
Bundy tube still retains the advantage of higher rigidity, which means less volume expansion under pressure.
