Powder metallurgy mainly uses metal powder as raw material, and makes it into the shape we need through certain processing technology. This processing technology is very similar to the production of ceramics, so a series of powder metallurgy techniques can also be used for the preparation and production of ceramic materials. This article will introduce the relevant knowledge of powder metallurgy process in detail, and understand the advantages and disadvantages of powder metallurgy process.
What Is Powder Metallurgy?
Powder metallurgy is a science and technology that studies the manufacture of metal powder, and uses metal powder (sometimes also adds a small amount of non-metal powder) as raw materials to manufacture materials or products through mixing, forming, pressing, sintering and necessary subsequent processing. It is a mass production method with little or no cutting, which can produce structural parts with complex shapes and high structural strength at a lower cost; it is the main method for mass production of bearing self-lubricating parts at a lower cost.
Because powder metallurgy can ensure the correctness and uniformity of material cost ratio, and powder metallurgy method can be pressed into the final size of the compact, without or little need for subsequent mechanical processing. Therefore, it can greatly save the amount of metal and reduce the cost of the product. When the product is manufactured by the powder metallurgy method, the metal loss is low, while the metal loss is high when the general melting and casting method is used. Therefore, most refractory metals and their compounds, oxide dispersion strengthened alloys, porous materials, ceramic materials and cemented carbides can only be manufactured by powder metallurgy methods.
Advantages of Powder Metallurgy Process
1. Special materials can be processed.
The method of material powder metallurgy can manufacture refractory metals as well as compounds, pseudo-alloys, and porous materials.
2. Save metal and reduce costs.
Because powder metallurgy can be pressed to final size green compacts, no mechanical processing is required. The loss of metal produced by this method is only 1-5%, while the general processing will consume 80% of the metal.
3. Preparation of high-purity materials.
The powder metallurgy process does not melt the material during the material production process, so it will not mix impurities brought by other substances, and the sintering is carried out in a vacuum and reducing atmosphere, which is not afraid of oxidation and will not pollute the material. Therefore, the product purity is relatively high.
4. Correctness of material distribution.
The powder metallurgy method can ensure the correctness and uniformity of the material composition in the proportioning.
5. Mass production reduces costs.
Powder metallurgy is suitable for the production of products with a large number of uniform shapes, such as gears and other products with high processing costs, which can greatly reduce production costs.
Disadvantages of Powder Metallurgy Process
1. The strength and toughness of powder metallurgy products are poor.
Due to the compaction formed by powder, the internal pores cannot be completely eliminated. Therefore, the strength and toughness of powder metallurgy products are worse than those of castings and forgings with corresponding components.
2. Powder metallurgy cannot be made into large products.
Since the fluidity of metal powder is worse than that of molten metal, its shape and size will be limited to a certain extent, and its weight will not exceed 10 kg.
3. The cost of compression molding is high.
Due to the high cost of stamping, it is only suitable for mass production.
Development of Powder Metallurgy Products
1. High-quality structural parts.
Powder metallurgy is representative of iron-based alloys, which will develop to large-volume precision products and high-quality structural parts.
2. High-performance alloys.
Powder metallurgy manufactures high-performance alloys with uniform microstructure, difficult to process and completely dense.
3. Mixed-phase special alloys.
Powder metallurgy uses an enhanced densification process to manufacture special alloys that generally contain mixed-phase compositions.
4. Composite parts.
Unique processing and composite parts with non-general forms or compositions.