Aluminium extrusion technology starts just as the foundation of the building you desire to construct is laid. Or in the construction of the bicycle you may purchase for your child. Sometimes you see it on the billboards, and sometimes on the systems heating your home. A technology that exists for you to enjoy your life …
Well, have you ever wondered about application of this technology?
Let us help you.
Firstly, we should explain three basic concepts necessary for extrusion by a simple approach.
» Aluminium raw material
» Extrusion press
» Mold
Circular cross-section aluminium alloy raw materials are used in the technology. These are called billets and the products we get at the end of the process just in the form we desire are presented to the people. By use of the extrusion press, we generate the hydraulic pressure that is necessary for ensuring flow of the billet through the mold and making it into profile. The mold is a tool produced from hot work tool steel, which is used in order for the profile to get its shape after extrusion.
Simply, the extrusion process is like squeezing toothpaste out of a tube. There is an opening at the end of the tube and when we apply pressure manually there occurs a flow in shape of that opening.
Let's go into details. Now you will see the complexity of the process together with the conditions on which it depends.
Each billet taken from the stock is the starting point of the process. Quality of the output product reflects the quality of the billet. This shows how important that the alloying of the ladle metallurgy when the billet is still liquid metal, subsequent optimization of the casting parameters and homogenization thermal process after the casting.
We should prepare the billet for the extrusion before delivering it to the press line and inserting it into the sleeve by help of stamp which will apply the main pressure. We perform this preparation by annealing the billet. This step reduces the extrusion pressure necessary as the billet softens by the effect of heat; and, furthermore, solution treatment also performs the function of the thermal process with the former being the firsEdgins in the improvement of the mechanical characteristics of the profile in the subsequent stages. For thermal stability, high temperatures are achieved in the press sleeve and mold. The said temperatures vary depending on the alloy of the billet we shall use as well as the extrusion conditions.
When necessary temperatures are reached, now the billet from the annealing furnace is cut hot to the desired length and placed into the sleeve where it will be subject to pressure via punch. With the friction increased under the pressure conditions inside the sleeve, the material that remains inside the billet flows via the metal dead zone constituted by the outer surface of the billet between the mold and sleeve through the material mold gap to form the section of the mold. And now the billet accumulated in the dead zone metallurgically contains a layer of oxide and this layer is cut off from the mold as intermediate work after pressure. The profile obtained from the mold is again cooled down quickly in the gas or liquid environment depending on the cooling sensitivity and necessity. This is the second step applied to improve the mechanical characteristics after the solution treatment.
After cooling, the long profile along the conveyor is first subject to cold stretch treatment and then cut to the desired length. Objective of the stretching operation is to eliminate any remnant tensions, if any, and thus ensure dimensional linearity.
And the travel of the billet in the extrusion press comes to an end. The route it will follow from now on depends only on the requests of the customer.
If you have any interest in this technology and have any request from us, we would be pleased to response to any questions you may ask by calling our SOLUTION and SERVICE PLATFORM.