What-are-the-secondary-operations-in-powder-metallurgy?

Powder Metallurgy’s traditional secondary operations

In the production process of powder metallurgy, the required product form is formed first through high-pressure molding and then through the sintering process. However, secondary processing can also be added to achieve other product requirements. The usual purposes of secondary addition in powder metallurgy are increasing product tolerances, sealing pores, making the surface better to enhance the corrosion resistance of the product, enhancing the hardness of the product, etc.

powder metal parts

Some of the most popular secondary processes in powder metallurgy are:

1. Sizing

Sizing in powder metallurgy, the product by making sizing molds. The specific process is to put the sintered product into a shaping mold and squeeze it twice.

Benefits: It can improve product accuracy, the tolerance can be increased by 50%, and the density of the product can be increased by 5%-15%, improving the smoothness of the product. Through size adjustment, the product gets R-angle edges, bulges or grooves, etc.

2. Machining

Since the accuracy of powder metallurgy is average, and some structural powder metallurgy molds cannot meet the requirements, later secondary processing is required to meet the drawing requirements.

Mechanical processing is often used as a solution. Machining can be carried out by grinding, turning and milling,

3. De-burring

After powder metallurgy products are sintered and formed, some small burrs may be left, which require grinding, polishing, etc.

process to remove these burrs and make the product smoother without affecting product performance.

4. Maceration

Powder metallurgy is formed by sintering powder. There are many pores in the product. The process of filling the pores with other materials is impregnation.

Commonly used materials for filling pores are oil, resin, copper, etc.

Purpose to improve product sealing and corrosion resistance

5. Placing

Chrome plating, zinc plating, PVD plating

Iron-based powder metallurgy products use electroplating to improve the corrosion resistance of the product. However, since there are pores inside the product after sintering, it is best to be impregnated first and then electroplated.

6. Black Oxide

Blackening treatment is divided into chemical blackening and logistics blackening. It usually refers to a processing method that darkens or blackens the surface of an object. Including oxidation, black plating, etc. These methods can change the appearance color of the object and improve the corrosion resistance the product surface.

7. Steaming

Usually, only iron-based powder metallurgy products are steam-treated. This secondary operation can produce a thin oxide layer, which can improve the product’s corrosion resistance, pressure resistance, overall hardness, and magnetism.

8. Carburizing

Carburizing heat treatment is mainly gas carburizing, which is to achieve surface hardening of low-carbon steel products through gas carburizing during the heat treatment process. Improving the surface hardness is often used in the surface treatment of gears.

sintered parts

In summary, these eight methods of secondary processing of powder metallurgy, through which they optimize the shortcomings of the powder metallurgy process, are enhanced in terms of hardness, strength, corrosion protection, and increased density. For more information, please feel free to contact us

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