Powder Metallurgy

Whenever you go to market and ask for a part made of alloy (which of course cannot be made by melting and adding to each other) what does the shop-keeper does? Well he simply hands you that part. And how he does it? Now don’t tell me he buys it from a manufacturer. The part is actually made from powder metallurgy. Now ‘powder metallurgy’ is a term which holds innumerable opportunities in industries in future (and of course in present era also).
So, what is powder metallurgy? Powder metallurgy incorporates a use of metallic powders to make products. By using this technology we can actually mix and form practically any composite material. Say for example we can also make self lubricating bearings by incorporating steel with graphite!
The process starts with ‘Blending of powders’ in which the two powders are mixed thoroughly to achieve uniformity in the part.



The next process is ‘Compacting’.In this process the powders of metals or required material is then put in a mould and compressed.The force normally applied is around 100 to 1000MN/m2 .The process can be either mechanically operated or hydraulically operated.The next process then is ‘Presintering’. This is done to remove lubricants or binders if any.Product which you obtain after presintering is called a ‘briquette’ Presintering is nothing but heating the powder in the die so that the mould becomes a little hard to carry around and take the shape of the mould.This process is mostly performed and can be excluded for certain applications.In case of Tungsten carbide ,it is machined after presintering, because tungsten carbide has a property of hardening so much so that it is impossible to harden the product after ‘Sintering’.Sintering is carried out mostly in controlled atmospheres.We can achieve final strength by this process. There are many secondary operation like coining,plating,broaching etc.They are done as required.Well this process is highly automated and precise dimensional tolerances can be met.Labour costs are also saved as unskilled labours can be employed.We can also manufacturesmagnetic cores having special properties.The advantages are many and disadvantages are few like the raw material i.e.; pure raw material is expensive to produce.There is no existing process which can produce metal powders cheaply.Also they have relatively poor plastic properties as compared to components made up of alloys and metals.However you can have any material component if you have got this technology.And here lies its importance.