Bundy tube

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

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.


It may be zinc or terne coated for corrosion protection. It is used in automotive hydraulic brake lines 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 Automotive.

Kunifer pipe[edit]

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.[1] Kunifer pipe has since been adopted by European automakers Volvo, Rolls-Royce, Lotus Cars, Aston-Martin, Porsche, and Audi.[2] Bundy tube still retains the advantage of higher rigidity, which means less volume expansion under pressure.


  1. ^ A.G. Imgram and D.K. Miner, Paper 690530, Mid-Year Meeting, May 1969
  2. ^ "Copper-Nickel Automotive Vehicle Brake Tubing". Copper Development Association. Retrieved September 9, 2006.