Advantages of Seamless Aluminium Tube/Pipe
● Without any weld seams, preferred for pressure vessels
● More uniform anodizing appearance, especially on heavier wall sections
● No weld seams that could split informing operation
● Increased structural integrity
● Good mechanical properties
● Good corrosion resistance and oxidation resistance
Applications of Seamless Aluminium Tube/Pipe
Aluminium seamless tube is used for virtually any type of application, from high pressure and mechanical to architectural and framing, typically used for pressure vessels, hydraulic cylinders, compressed gas cylinders, driveshafts, lighting applications, and bus conductors.
● Critical pressure ratings
● Demanding forming applications
● Critical strength requirement
● Uniform anodizing appearance
The Difference Between Seamless Tube and Structural Tube (Slit Tube)
● Different tooling: the seamless tube is extruded over a mandrel utilizing a hollow billet and is the only tubular product recommended for pressure applications. The structural tube is extruded over a bridge or porthole die.
● Seamless tube without any welding joint, the structural tube with an indistinguishable weld seam.
● Compared to a seamless tube, a structural tube is more able to use multi-hole dies for smaller diameter sizes to improve productivity and decrease costs.
● There’s a little difference in appearance. For seamless tubing, the seamless tube's inner and outer walls are smooth and clean-burning or cracking on the surface; The appearance of the slit tube is generally smooth.
The Production Process of Seamless Aluminium Tube
Creating an extrusion without seams along its length. This is done by pushing the mandrel from the back into the blank. The tip of the mandrel (at the other end of the die) passes almost all the way through the blank and is very short from the extrusion die. This leaves a small gap between the mandrel and the mould through which the metal can pass.
After the spindle is locked in place, the plunger of the extruder acts on the blank. As the pressure increases, the material is forced to pass through the gap and an extrusion tube appears on the other side.
Aluminium is a good choice for seamless extrusion because it is a very tough material. By heating the billet to a point slightly below its melting point, ductility is further improved and the pressure load is reduced. Most grades of aluminium can be extruded, but some are easy to work hardening, which reduces the maximum extrusion speed. Therefore, the most common extrusion grades are 6061 and 6063, which do not harden.
After extrusion, the heat pipe is cooled and often stretched to improve straightness when a higher quality tube, a thinner wall, or a more uniform size is necessary after the drawing process.
6061 Seamless Aluminium Tube
Grade 6061 seamless aluminium tube has good corrosion resistance, formability, and processability.
An alphanumeric suffix attached to an alloy, such as 6061-T6, indicating tampering or hardness. Taking 6061-T6 as an example, "T6" means that it has undergone solution heat treatment and artificial ageing treatment.
6061 is still the most popular. It is famous for having a good appearance after the tube has been anodized.
6063 Aluminium VS. 6061 Aluminium
Similarly, 6061 aluminium is usually compared with 6063 aluminium, because these two grades are usually used to manufacture structural parts. Although the two materials are very similar and often have negligible differences in application, 6061 provides significantly higher yield strength for parts requiring special forces.
Regardless of your choice, 6061 or 6063 aluminium will provide high weldability and formability for your project.
Yield Str. (PSI)
Ultimate Str. (PSI)
ASTM A53 Pipe