Steel Brake Line Tubes/Pipes – Automotive Hydraulic Tubing
Engineered Industries Limited offers the steel tubes/pipes for automotive brake lines per the major specifications of the automotive industry.
The base tube is the Bundy-weld (double wall copper brazed) steel tube, which is complies to ASTM A25, SAE J527 and DIN 74234 etc.
Regular Size & Stock
The steel brake lines s of the following table listed sizes are feasible to manufacture; among them, thickness of 0.7mm and 1mm are available in stock most of the time or to be produced upon being ordered.
| OD, mm | Wall Thickness |
| 4.76 | 70.1 |
| 6 | 91.5 |
| 6.35 | 97.5 |
| 7.94 | 125.0 |
| 8 | 126.0 |
| 9.53 | 152.4 |
| 10 | 160.5 |
| 12 | 185.1 |
Above data for 0.7mm wall thickness only.
Dimensional Accuracy
| OD | Tolerance | Wall Thickness | Tolerance |
| <4.76 | ±0.05 | 0.5 | ±0.07 |
| 4.76-8 | ±0.08 | 0.5-0.7 | ±0.08 |
| 8-12.7 | ±0.10 | 0.7-1 | ±0.09 |
| >12.7 | ±0.12 | 1-1.3 | ±0.1 |
Material
The Bundyweld tubes are made from low carbon steel strips (grade BHG2) which is manufactured by Bao Steel Group. The chemical compositions are as following:
| Element | C | Si | Mn | P | S |
| Standard (max, %) | 0.06 | 0.03 | 0.3 | 0.03 | 0.03 |
Mechanical Properties
| Tensile Strength | 42000psi (290MPa) |
| Yield Strength | 26100psi (180MPa) |
| Elongation | ≥25% |
| Expansion | ≥20% |
Inside Surface Cleanliness: 0.16g/m2 , max
Burst Pressure
| OD, mm | Burst Pressure, MPa, (for 0.7mm 0.028″ wall) |
| 4.76 | 110.3 |
| 6 | 84.5 |
| 6.35 | 79.3 |
| 7.94 | 61.9 |
| 8 | 61.4 |
| 9.53 | 50.7 |
| 10 | 48.2 |
| 12 | 39.6 |
| 12.7 | 37.3 |
Above data for 0.7mm wall thickness only.
Surface Treatment
The further surface treatment enables the tube/pipe capability to withstand corrosion for a much longer time compared with the original copper plating of the tube. With the following extra protections, they can be used for automotive brake, fuel, transmission cooling, and power steering lines.
The final tubes meet major standards like JASO M101, GM123M/124M etc., and the are strictly tested to ensure the safety driving of vehicles on and off road.
- Zinc plating (electroplating, or hot dip galvanizing).
- Zinc + Polyvinyl Fluoride (PVF) coating.
- Zinc + Nylon (PA) coating.
- Zinc + Alum-rich epoxy.
Manufacture Standards
For Bundy tube manufacture, generally standards of China, 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
- USA ASTM A254, SAE J527, GM123M/124M
- Japan JASO M101
- Russia GOST 11249
- Europe DIN 74234
- India IS 8119