What are the Secondary Operations in Powder Metallurgy?

November 9, 2020

One sustainable metal-forming process that is being utilised by industries today is known as powder metallurgy. This specific process is done by heating compacted metal powders below their melting points, which can help avoid and reduce the use of any metal removal or machining processes. Moreover, powder metallurgy can easily cut yield losses without spending many resources.

The basic processes in powder metallurgy usually involve the production of metal powder, the compaction of the powder, and the consolidation of the powder into a solid component under specific conditions. While these processes can already produce excellent metal products, tons of secondary operations can be added to achieve more benefits. Secondary operations in powder metallurgy can typically enhance corrosion-resistance of the product, seal its pores, and many more.

Some of the most popular secondary operations in powder metallurgy are as follows:


One way to squeeze the thickness and improve the dimensional precision of a powder metallurgy product is through sizing. This secondary operation can bring correct specifications of a part, improve its tolerance limits by up to 50%, and cut down the overall cost processes significantly. With sizing, a part can obtain rounded-off edges, raised or grooved features, better surface finish, and other surface features.


Machining is another secondary operation in powder metallurgy that can help industries solve certain problems. If the sintering process cannot hold the required tolerances of a metal part, then machining can serve as a workaround. Machining can be conducted through grinding, turning, and milling, which can all help minimise overall lead time, energy consumption, and material waste.


Once metal products are formed, there might be some small metal protrusions that are normally left. These small metal protrusions are known as burrs, which can be unpleasant to metal parts if they will be left untouched. Therefore, a secondary operation called deburring is normally done to remove these little imperfections. After all, burrs can be sharp and may affect or even harm the performance of the product.


Another secondary operation in powder metallurgy that can bring a lot of features to metal parts is known as coining. It is a process of applying pressure on the surface of material so that it can obtain closer tolerances and smoother surfaces. This process is normally done for parts that cannot be moulded during compaction, preventing the need to replace tooling several times.


Parts and products that are created out of powder metallurgy can be porous, which is why some fabrication companies would perform the process of impregnation. Impregnation or infiltration is the process of filling in most of the pores with various elements. These elements can be plastic, resin, copper, oil, or other materials. The whole pressure is pressure-tight, eliminating the risk of leakage.

Steam Treating

Sintered products that are based on iron can maximise the advantages of steam treating. This secondary operation can produce a thin oxide layer that can effectively blend in with the iron surface. The thin oxide layer that is created by steam treating can improve a product’s corrosion resistance, pressure tightness, overall hardness, and some magnetic properties.

For more information about secondary operations in powder metallurgy, feel free to contact us at PM Distributors.


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