Bundy tube, is a type of thin wall, small diameter steel pipe named after the person who invented its fabricating process.
It is made by two layers of steel strips, brazed by copper between the two layers. A single piece of steel strip with copper plating on both sides, is rolled up 720 degrees into a round tube, heated to more than 1000 degrees to melt the copper coating, and cooled to have the two layers of steel brazed together by the copper coating. This type of tube is called Bundy tube.
Bundy tube is widely used in automotive hydraulic brake lines, for it’s balanced performance in strength, flexibility and reliability when being bended and flared to be intalled on vehicles. It is also used in heat exchanging fields like ACR, to replace the traditionally used single wall welded steel tube.
Material
Cold rolled steel strip chemical compositions (%):
C | Si | Mn | P | S |
0.02-0.08 | 0.03 max | 0.15-0.45 | 0.030 max | 0.030 max |
Inside Cleanliness: 0.16g/m2
Accuracy (mm)
Outside Diameter | Wall Thickness | ||
OD | Tolerance | Thickness | Tolerance |
<4.76 | ±0.06 | 0.50 | ±0.07 |
>4.76-8 | ±0.08 | >0.50-0.70 | ±0.08 |
>8-12.7 | ±0.10 | >0.70-1.00 | ±0.09 |
>12.7-16 | ±0.12 | >1.00-1.3 | ±0.10 |
Mechanical Properties
Tensile Rm | Yield ReL | Elongation A50mm* | Hardness HR30T |
290MPa min | 180MPa min | 20% min | 65 max |
* By changing annealing duration or cold drawing, mechanical properties can be adjusted according to buyer’s request; elongation can be adjusted to 30% min if requested.
More properties and suppliers about this tube can be learned from here.
