Bundy tube, also called Bundy pipe, is a double wall copper brazed steel tube. The manufacture of Bundy tube is a continuous process of rolling a copper coated steel strip through 720 degrees, brazing the outer and inner circle of the strip together by the melted copper layer to form a round tube with a continuous circular seam, and annealing. We are using fully automatic production lines with online process monitoring and continuous fabrication of the Bundy tubes.
- A copper plated steel strip is pulled into the primary tube rollers, and become 720 degrees wrapped after going through a set of the rollers.
- Then the wrapped tube goes into the welding chamber where the tubes are brazed. The temperature within the chamber is controlled above the copper melting temperature, so the copper layers are melted and spread into the steel surfaces. The tube is heated here in the chamber with protection gas filled so there is no oxidizing of the copper or steel, and also no water will be left to avoid any rust.
- After the welding stage, the tube goes into the cooling section where it gets cooler, and also it is monitored online simultaneously by the Eddy current scanning device. Any abnormal section shape or un-seamed welding would be observed from the monitor screen.
- The tubes are finally wound to be easily packed and stocked.
This process of Bundy tube production, compared with other methods, are widely accepted for its high production rate yet instant monitoring of the welding quality.