Powder metallurgy product

honggarae 28/11/2022 444

Application

The application range of powder metallurgical products is very wide, manufactured from ordinary mechanical to precision instruments; from hardware tools to large machinery; from electronics industry to motor; from civilian industries to military Industry; from the general technology to tip high technology, you can see the figure of the powder metallurgy process.

Development History

The powder metallurgical method originated in more than 3,000 years ago. The first method of manufacturing iron is substantially used in powder metallurgy. The development of modern powder metallurgical technology has three important signs:

1, overcoming difficulties arising from difficult melt metal molten casting. In 1909, the electric lamp tungsten wire was manufactured, and the development of powder metallurgy was promoted; the emergence of powder metallurgical carbide in 1923 was hailed as the revolution in machining.

2, and the process of successful preparation of porous oil bearing; the development of powder metallurgical iron-based mechanical parts has given the advantages of powder metallurgical and less cutting or even cutting.

3, to the more advanced new materials, new processes development. In the 1940s, there was a material such as metal ceramics, dispersion and other materials. At the end of the 1960s, the powder high-speed steel, powder high temperature alloy appeared successively; using powder metallurgical forging and thermostatic static pressure that has been capable of manufacturing high-strength parts.

Advantages

1, most of the difficult-melted metals and their compounds, fake alloys, and porous materials can only be produced by powder metallurgy.

2, since the powder metallurgical method can be pressed into a final size of the block, without the need or rarely needs to be maintained, the metal can be greatly saved, and the product cost can be reduced. When manufacturing the product with a powder metallurgy method, the loss of metal is only 1-5%, while the metal's loss may reach 80% when producing a generally molten casting method.

3, since the powder metallurgical process does not melt in the production process, it is not afraid to mix the impurities from the 坩坩 and the deoxidizer, and the sintering is generally carried out in a vacuum and reducing atmosphere, not afraid Oxidation, no contamination of materials, so it is possible to make high purity materials.

4, the powder metallurgy method ensures the correctness and uniformity of material component matching.

5, powder metallurgy is suitable for producing a product of the same shape, especially the processing costs such as gears, and manufacturing with powder metallurgical method can greatly reduce production costs.

Disadvantages

Powder metallurgical processes: Overall Disadvantages: 1) The total apertures inside the article; 2) The intensity of ordinary powder metallurgical products is more than the corresponding forgings or castings. Low (approximately 20% to 30%); 3) Since the fluidity of the powder is far less fluent in the formation, there is a certain limit on the shape of the product structure; 4) The pressure required to press the forming is high, and the product is suppressed. Device capabilities, etc .; 5) high pressure mold costs, generally only applicable to batch or large production. Metal powder: The quality of the final product is difficult to control it; the metal powder is expensive; the powder is not smooth from hydraulic law, but has a certain limit of product structure shape. Manufacturing equipment, method: 1) Pressure machine: often need to use expensive strong press 2) stamper: a consumable product, cost is 3) sintered furnace 4) Powder is easy to oxidize, mixed for a long time 5) Dimensions and shapes are restricted.

process

1, the preparation of the raw material powder. The existing powder method can be generally divided into two categories: mechanical law and physicochemical method. The mechanical method can be divided into: mechanical pulverization and atomization method; physical chemistry is also divided into: electrochemical corrosion, reducing method, chemical legal, reduction - chemical legal, gas phase deposition method, liquid deposition method, and electrolysis. Among them, the application is the most widely reduced method, atomization method and electrolysis.

2, the powder is formed into a blank of the desired shape. The purpose of forming is to make a certain shape and size of the billet and have a certain density and intensity. The method of forming is basically divided into pressurized molding and no pressure molding. The most application of the compression molding is molded.

3, the sintering of the blank. Sintering is a key process in powder metallurgy. The molded billet is sintered to obtain the desired final physical mechanical properties. Sintering is divided into unit system sintering and multi-system sintering. For the solid phase sintering of the cell and the multi-element, the sintering temperature is lower than the melting point of the metal used; the sintering temperature is typically lower than the melting point of the plug, but higher than the fusser component. Melting point. In addition to normal sintering, there is also a special sintering process such as loose sintering, filling method, and hot pressing method.

4, the sequence of products. After sintering, it can take a variety of ways according to the product requirements. Such as finishing, dip oil, machining, heat treatment and electroplating. In addition, some new processes have been rolled in recent years, and forging is also applied to the processing of the sintering of powder metallurgical materials, and the ideal effect is achieved.