Extruding of Aluminium and Aluminium Alloys – The Extrusion Process, Economics and Design

Aluminium is recognized as one of the materials that will shape the cars of the future. KMC Aluminium is considered an innovative company in the application of aluminium extrusion technology for the automotive industry.

Aluminium and Extrusion

Aluminium is particularly suitable for the extrusion process due to its excellent plasticity at extrusion temperature. Only a minor degree of work hardening takes place at this temperature and sufficient hot working is done to improve the metallurgical structure of the extrudate.

The extrusion process

In the extrusion process, a cylinder of solid metal (extrusion ingot) is made into a continuous length of uniform cross-section by forcing it to flow at very high pressure through a die orifice that is the same shape as the required product. .

Extrusion is normally a hot working operation, the metal is heated to achieve the optimum level of plasticity, although in some cases the operation can be done cold.

The direct extrusion process

Two methods of extrusion are used, direct extrusion and indirect extrusion. In the direct extrusion method, a die is placed at one end of the container containing the ingot. The ram enters the chamber from the opposite end and the metal is forced forward through the die hole.

The normal procedure is that an ingot is loaded into the press and a certain length is extruded, leaving a cap which is cut off. Due to friction between the billet and the vessel wall, the center of the billet is extruded first, leaving a dead zone around the periphery of the die plate.

Prevention of contamination during extrusion

There is also a tendency for the surface layers of the billet to move inward along the face of the follower place and protrude through the center of the section. If this is allowed to happen, rust and other debris get into the section and an extrusion "defect" occurs. For this reason, it is practiced to stop the extrusion at such a point as to leave the waste in the container. Objectionable structural conditions at the end of the extruded shape are avoided when the stop is removed.

Extrusion of Aluminium alloys

Aluminium alloys differ in extrusion. In general, the higher the alloy content and the higher the strength, the more difficult the extrusion will be. The ease of extrusion decreases as the C.C.D. increases Increases with increasing shape thickness, with a shape of uniform thickness being the easiest to extrude. The more unbalanced an asymmetrical shape is, the more difficult it is to extrude.

Such is the general extrusion capacity of aluminium profile manufacturers that it is precisely these configurations that have explained the great growth in the aluminium extrusion market.

Extrusion: a profitable process

The “tooling” required for extrusion (the dies and go right here other items) are fairly inexpensive compared to those required for other production methods from list of aluminium extrusion companies in India, so their initial cost can be more easily amortized. Even in relatively small production runs, aluminium extrusions can be less expensive than alternative processes, especially when secondary savings from reduced machining, finishing, and simplified assembly are taken into account.

With their added benefits in many areas, they often provide the only cost effective product solution.

Extrusion cutting lengths

After extrusion, the section is guided down the table by a "knob" onto a moving belt of slats. On completion of an extruded length, the section is cut at the press end and lifted off the slat belt by eccentric rotating arms. The extrusion is then transferred by moving beam to the "stretcher bay" where it is straightened by controlled stretching to remove minor misalignments. It is then cut to size using tungsten carbide tipped saws.

States of heat treatment for extruded aluminium alloys

If extrusion is required in a solution heat treatment condition (T4), it is released at this stage. If full strength aged material (T6) is required, the extrusion is cooled and then given a precipitation treatment (artificially aged) before release. For material with T5 temper, limited cooling occurs at the exit of the press, but the extrusion goes directly to the precipitation treatment without quenching.

About Us

KMC Aluminium is a Chennai-based manufacturer producing and supplying high quality aluminium extrusions. Over a short period of time, KMC has emerged as one of the leading manufacturers of aluminium extruded products in the country. KMC is an ISO/TS 16949:2009 company with its manufacturing facility located in Chennai.

Website - https://kmcaluminium.com/