Конструкциялық материалдар және термоөңдеу Конструкционные материалы и термообработка Constructional materials and heat treatment Учебное пособие для специальности: 5В071200– «Машиностроение»
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montaev s h
- Бұл бет үшін навигация:
- Production of cast iron.
- Products of domain production.
- Classification of cast iron.
| Lecture №4.
Cast iron. 1. Production of cast iron. 2. Classification of cast iron. 3. Structure and properties of cast iron. 4. Gray and high-strength of cast iron . 5. Malleable and alloyed cast iron. Production of cast iron. The iron alloy with carbon, with the content of carbon more than 2,14 % is called as cast iron. Cast iron is melt in the blast furnaces. The modern blast furnace is the high- efficiency unit, height 30m. and more, productivity to 5000t cast iron per day. Products of domain production. Products of domain production are cast iron, domain slags and domain gases. Cast iron depending on further use are subdivided on: Steel-making iron -which are used entirely for steel melting. Their production makes 70 % from all production of cast iron. Foundry iron go for molding of various pig-iron products. Their production makes 20 % from all production of cast iron. 185 Special iron are used for a steel deoxidation. Their production makes 10 % from all production of steel. Blast furnace slag after crushing and processing are used for manufacturing of bricks, as additives in cement and as an insulating material. Blast furnace gases after cleaning and an dewatering are used for heating of various rooms. Classification of cast iron. Cast iron is called an iron alloy with carbon and other elements containing more than 2,14 % s. In metallurgical production cast iron is melt in blast furnaces. Received cast iron subdivide on: steel-making iron, special iron (ferroalloys) and foundry. Steel-making and special iron is used for the subsequent processing in steel. Foundry iron (about 20 % of all melted cast iron) is sent on machine building plants for use when manufacturing cast preparations of details (molding). Not alloyed constructional cast iron for production of moulding in mechanical engineering has the following chemical composition, %: 2-4,5С., 1-3,5 Si., 0,5-1 Мn., content of impurity: no more than 0,3 % of S., no more than 0,15 % . The wide circulation of cast iron in the industry is caused by an optimum combination of various properties: technological (foundry, workability cutting), operational (mechanical and special) and technical and economic indicators. Characteristic of cast iron is that carbon in an alloy can be not only in dissolved and in the connected condition (in the form of chemical connection- cement-carbide), but also in a free condition - in the form of graphite. Classification of cast iron is carried out on the following signs: - on a carbon condition - free or connected., - in a form of inclusions of graphite - lamellar, vermikulyarny, spherical, temper., - as structure of a metal basis - ferrite, pearlite., also cast iron with the mixed structure: for example ferrite-pearlite., - on chemical structure - not alloyed cast iron (general purpose) and alloyed cast iron(special purpose). Depending on a form of allocation of carbon in cast iron distinguish: - white cast iron in which all carbon is in the connected condition in a look cement carbide., - molted iron in which the main amount of carbon (more than 0,8 %) is in a look cement carbide, - gray cast iron in which all carbon or its most part is in a free condition in the form of lamellar graphite., - the chilled cast iron in which the bulk of metal has structure of gray cast iron, and a superficial layer - white., - high-strength cast iron in which graphite has a spherical form., 186 - the malleable cast iron which is turning out from white by annealing at which carbon passes to a free condition in the form of temper graphite. жүктеу/скачать 1,99 Mb. Достарыңызбен бөлісу:
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