Advantages and Disadvantages of Powder Metallurgy
The process of manufacturing of shaped components or semi-finished products such as bar and sheet from metal powder is called as Powder metallurgy.
The technique of powder metallurgy combines unique technical features with cost effectiveness and generally used to produce sintered hard metals known as ‘carbides’ or ‘tungsten carbides’.
This technique deals with the production of metal and non metal powders and manufacture of components.
Powder metallurgy is generally used for iron based components.
The powders used as raw material can be elemental, pre-alloyed, or partially alloyed.
Elemental powders like iron and copper are more compressible and produce pressed compacts with good strength.
Pre-alloyed powders are harder but less compressible therefore require higher pressing loads to produce high density compacts.
Powder metallurgy technique has many advantage as well as limitation.
Some of the Advantages of Powder Metallurgy are as follows;
1. Powder metallurgy produces near net shape components. The technique required few or no secondary operations.
2. Parts of powder metallurgy can be produce from high melting point refractory metals with less cost and difficulties.
3. The tolerance of components produced by this technique have quite high tolerance, therefore no further machining is not required.
4. This technique involves high Production Rate along with low Unit Cost.
5. It can produce complicated forms with a uniform microstructure.
6. Powder metallurgy has full capacity for producing a variety of alloying systems and particulate composites.
7. This technique has flexibilities for producing PM parts with specific physical and mechanical properties like hardness, strength, density and porosity.
8. By using powder metallurgy, parts can be produced with infiltration and impregnation of other materials to obtain special characteristics which are needed for specific application.
9. Powder metallurgy can be used to produce bi-metallic products, porous bearing and sintered carbide.
10. Powder metallurgy makes use of 100% raw material as no material is wasted as scrap during process.
Disadvantages of Powder Metallurgy:
1. The production of powder for metallurgy is very high.
2. The products of metallurgy can have limited shapes and features.
3. This technique causes potential workforce health problems from atmospheric contamination of the workplace.
4. The tooling and equipments require for powder metallurgy are very expensive, therefore becomes main issue with low production volume.
5. It’s difficult to produce large and complex shaped parts with powder metallurgy.
6. The parts produce by powder metallurgy have low ductility and strength.
7. Finally divided powder like aluminium, magnesium, titanium and zirconium are fire hazard and explosive in nature.
8. This technique is not useful for low melting powder such as zinc, cadmium and tin as they show thermal difficulties during sintering operations.