Конструкциялық материалдар және термоөңдеу Конструкционные материалы и термообработка Constructional materials and heat treatment Учебное пособие для специальности: 5В071200– «Машиностроение»
partially reacts with carbon and is allocated in the form of gas bubbles of an
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montaev s h
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- Tool steel.
partially reacts with carbon and is allocated in the form of gas bubbles of an oxide of carbon, making impression of "boiling" steel. Semi-killed steel on degree of their de-oxidation are intermediate between killed and rimming steel. Partially they de-oxidize in the melting furnace and in a ladle, and final in a mold at the expense of carbon containing in metal. Tool steel. The tool steel is intended for manufacturing of the cutting and measuring tool. To this group steel carry carbonaceous and alloyed steel with high hardness and wear resistance. The main criteria of a choice of steel for manufacturing of the cutting tool are its wear resisting-and heat resistance, and also steel should possess the hardness exceeding hardness of the processed material, and high durability in a combination to sufficient viscosity. Carbonaceous steel of the brands U7, У8, У10, У11, У12, У13 of ordinary quality or high-quality apply when manufacturing tool to cutting of materials of low hardness with small speeds. Low-alloyed steel with a small hardness penetration apply to manufacturing of the tool working at temperatures to 200-260zs. These steel, for obtaining operational characteristics, subject to incomplete training and low holiday. Training make in oil or hot environments. Steel of 7HF brand is applied when manufacturing the tool working with shock loadings - chisels, punches and gouge. Steel of the XB4 brand differs special hardness and wear resistance and is used when manufacturing tool for fair processing of metals (broaching, scraping tool, saws on metal and cutters for processing of firm metals by cutting). When manufacturing the high-efficiency tool intended for work with high speeds of cutting, are applied fast-cutting steel. The main dignity of the last is high heat resistance (it is provided with introduction of a significant amount of carbide-forming elements: tungsten, molybdenum, vanadium, cobalt). Fast-cutting steel subject to thermal processing of special types. For workability improvement by cutting after forging fast-cutting steel anneal at 800-860zs. Demanded heat resistance of fast-cutting steel gain after training and repeated water tempering. Distinctive feature of training of these steel is slow heating and warming up at 480 and 850?С in the environments preventing their 192 oxidation and an decarburization. For reduction of number of operations of water tempering after training of steel it process cold (-80?С). For increasing of wear resistance the tool from fast-cutting steel subject to cyanidation. On cutting properties of fast-cutting steel divide on: - normal productivity (tungsten Р18, Р12, Р9, Р9Ф5 and tungsten-molybdenum Р6М3, Р6М5), with heat resistance of the tool to 620?С., - the increased productivity, incorporating cobalt, or with the raised content of vanadium (brands R18F2, Р14Ф4), with heat resistance of the tool to 640?С. The tool from fast-cutting steel apply mainly to cutting of high-strength and hard to treat materials. Steel for the measuring tool possess high wear resistance and property to keep the stable sizes and a form of products for a long time. High-carbonaceous chromic of steel of brands X, HVG, HG, 9HS found the widest application for manufacturing of the measuring tool tempered to hardness of 57-60 HRC. Training carry out in oil at temperature 840-880. The tool of the increased accuracy subject to processing by cold at 50-80below. жүктеу/скачать 1,99 Mb. Достарыңызбен бөлісу:
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