The actual definition of pipe may change in context of the application for which they are used. Some of the industries using extruded pipes include plumbing, mining, gas transmission lines, beverages etc. However a popular definition of extruded pipes can be given as a rigid, hollow, long and having large diameter as compared to tubes. A basic difference between pipes and tubes lies in the fact that in case of Tubings, they are flexible and has relatively small diameter. Pipes can be extruded using plastics, along with metals like aluminium and rubber. They are discussed in detail here.

• Extruded Aluminium Pipe
  Extruded aluminium pipes are used in various critical applications. With state-of-the-art hydroforming operation there is a distinct possibility to shape it three-dimensionally in just a single operation. These pipes are extremely popular for their use in the automobile industry. The following image describes an extruded aluminium profile. Take note of the changes in cross sections throughout the entire length of the pipe.
  
  
  The principle behind this unique shape is described here. The profile is first positioned in a die. The die has an inner geometry that exactly replicates the shape of the profile to be extruded into finished component. As the die is locked very securely in a perfect position, then hydrostatic pressure is set up in the pipe (profile). The profile takes the shape of the die when the profile gets pressed against the die.
  
  
• Extruded Pipes of Plastic
  A very popular material for extruding Pipes is the thermoplastic material. A very popular equipment to extrude pipes is the Single screw extruder. In case of PVC twin screw extruders are applied. Dies in use are the same basic type that is used in the wire coating. A Good extrusion line for producing pipes must aim at reducing material cost and give tight tolerances. Plastic material are first fed into the hopper and then to a rotating screw. It is here they are heated up and subsequently softened. Consequently the pipe that is now softened up is forcibly passed through a die in continuous stream to form a pipe. Then they are passed through a cooling chamber and cut according to the required length. A simple extrusion line is shown in the image.
  
  
  

Materials used in the Extruded Plastic Pipes
Some of the popular plastic materials used includes:

• PVC
  The following image show clear extruded PVC pipes.
  
  
  
• Polyethylene
  Irrigation sector is one of the major user of PE pipes contributing to around 60% of the total PE market demand.
  
  
• HDPE
  
  
• Polypropylene