(Clad) Continuously Drawn Aluminum Pipe

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For the piping materials of car/room air conditioners

Picture of (Clad) Continuously Drawn Aluminum Pipe

Mandrel extrusion pipe extruded with a large indirect extruder produces a profile without joints (seams), giving it better dimensional precision than material produced in a cold-drawing process using a continuous extrusion machine (bull block) and producing stronger pipe material. Also, by combining different materials for the core and outer surfaces, indirect extrusion can produce clad pipe materials having inner and outer surfaces of different components.

Features

  • Continuous extrusion machines can supply long coils to automated assembly lines at high speed.
  • As pipe produced in this manner does not have the welding joints as does port hole extruded pipe, it maintains a high degree of airtightness, avoiding the corrosion that tends to set in first at the joints.
  • Mandrel extrusion produces material with excellent homogeneity and dimensional stability in the direction of longitudinal extrusion.
  • Clad pipes on which sacrificial materials are used demonstrate corrosion resistant. For surfaces that use solder, solder material can be affixed to bare material.

Applications

  • Piping materials for car/room air conditioners

Examples of use in automobile heat exchangers

Fig. Examples of use in automobile heat exchangers

Radiator tubes

Picture of Radiator tubes

Product Characteristics

Comparison of clad/unclad properties

Corrosion after CCT mixed cycle test (60 cycles)

Picture of Unclad pipe
Unclad pipe
Pitting corrosion overall on through walls
Picture of Clad pipe (exterior clad with Al-Zr sacrifice layer)
Clad pipe (exterior clad with Al-Zr sacrifice layer)
Corrosion spreads laterally, helping to prevent pitting corrosion

Comparison of growth in pitting corrosion using CASS test

Graph of Comparison of growth in pitting corrosion using CASS test
Use of clad pipe greatly slows the onset of pitting corrosion.

Production Technologies

Hollow material production methods

Mandrel method (seamless pipe)

This extrusion method uses a mandrel to pierce a billet. The space between the mandrel and the die determines the shape produced. In some cases, holes are drilled in the billet beforehand. This extrusion method produces shapes without welding seams.

Fig. Mandrel method (seamless pipe)

Porthole method (seamed pipe)

Porthole method (seamed pipe)
Billets are extruded through an arrangement of two male/female dies. The billet is forced through the male die and adheres in the female die, creating a hollow shape.

Fig. Porthole method (seamed pipe)

Production Process

Production process for continuously drawn materials

Fig. Production process for continuously drawn materials
Tube size: External diameter of 6 mm,
wall thickness 0.8 mm and up

Picture of Production process for continuously drawn materials

Bull block process (continuous extrusion)

Fig. Bull block process (continuous extrusion)