Конструкциялық материалдар және термоөңдеу Конструкционные материалы и термообработка Constructional materials and heat treatment Учебное пособие для специальности: 5В071200– «Машиностроение»
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| Lecture №10.
Powder alloys. 1. General information. Receiving metal powders. Formation and agglomeration. 2 . Finishing operations. Nomenclature of powder details. 3 . Corrosion-resistant alloys. Heat-resistant alloys. General information. Methods of powder metallurgy allow to receive alloys from the metals which aren't dissolving in each other at fusion, and also alloys from refractory metals. Powder metallurgy allows to receive porous materials and details from them, and also the details consisting from two (bimetals) and more of layers of various metals and alloys. Technological process of products production by the method of powder metallurgy consists of the following main operations: - receiving metal powder or mix of powders of diverse materials. - formation and agglomeration. - finishing operations. Receiving metal powders. Metal powders are received by mechanical and physical-chemical methods. At mechanical methods, powders are developed by crushing (crushing, grind) firm or dispersion (kinetic energy of air, water, inert gases) liquid metals without change of their chemical composition. 220 At physical and chemical methods there is a change of chemical composition and properties of an initial material (chemical restoration of metals from oxides, electrolysis of the melted salts, etc.). Characteristics of the main technological properties of powders are: - bulk weight - weight 1см ³ freely filled powder in grams. For production of high-porous products (filters) we use powders with a small bulk weight, and for the loaded details - with a big bulk weight., -fluidity - is the ability of powder to fill a form, in big degree influences uniformity of form filling by the powder and consolidation speed when pressing. - compressibility - is the ability of powder to be condensed under the influence of external loading, it is characterized by durability of coupling of powder жүктеу/скачать 1,99 Mb. Достарыңызбен бөлісу:
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