Faculty: Physical-metallurgical
Speciality: Treatment of metals by pressure
Presently in Ukraine by a continuous method pour out only 54,3 % îf steel. In spite of the measures and decisions accepted a government, stake on Ñontinuous Action Machine poured out of steel increased extremely slowly. Abroad it makes about 85 %.
By the most objective prognoses scarcely it will be succeeded to attain this number in the nearest 10 – 12 years. Therefore perfection of technology, expansion of assortment of operating figures, increase of the productivity, is the most actual questions now. It is similarly needed to mark that on the economic considering the martin production of steel became uncompetitive and in substantial volumes remained only in Russia and Ukraine. Taking into account a tendency to multiplying the stake of production of high-alloyed steels and alloys, most preferable is an elektrosteelmaking process.
In the near future the basic supplier of metal for the pipe purveyance of large section will be cogging meels (including blooming). In a number of cases it is conditioned not only the folded pattern of rental production but also requirements which pull out users to quality of purveyance. Such approach found a reflection in accepted GSTU 3-009-2000, in which requirements are regulated not only on geometry but also on the parameters of makrostruktury, fully.
Because of it researches which connected with the productions of pipe purveyance related to the improvement of technology take actual character, especially in the case of the use in place of bar of constantlypoured blooms.
A round purveyance is applied for the production of seamless hot-deformed steel pipes, circular wares (wheels), axes, wares for remaking processes, and similarly as an initial purveyance for the production of the calibrated types, periodic types of variable diameter, balls.
By a substantial step ahead both from point of set of equipment and from point of technology of production of pipe purveyance became specialized tubemaking rolling mill 900/750 the Dnepr Metallurgical Works of Dzerzhinskiy. A rolling mill is located in one line with blooming 1150, that allows to give out blooms (by a section ot 220õ260 to 300õ460 mm) transit without the intermediate warming up on a rolling mill 900/750. In the project assortment of rolling mill 900/750 the production of pipe purveyance is included a diameter 90 – 270 mm from steel of ordinary quality, high-quality and highest-quality. It is possible using also cold blooms after repair, as in a workshop there are methodical stoves for their heating. There is similarly an area of cleaning, cutting and slow cooling of purveyances. The temperature condition of rolling must respond to request: a temperature of end of rolling on blooming at rolling transit must be no less than 1100Ñ. A temperature began rolling in the rolling mill «900» of blooms must be at rolling of commodity purveyance of all brands not below 1070Ñ. For a remaking purveyance – not below 1020Ñ. Temperature of end of rolling of all brands became and types must be not below 970Ñ. At rolling of round purveyance in a rolling mill «900» with the purpose of exception of formation of trouser «stripes», after a pre-clean passage-way, the front end of rozkatu is additionally wrung out on the first caliber on 3-4 mm on length 250-300 mm («sharpening» is thus conducted) a clean passage-way is and then done.
A mastering attempt was done on a figure 900/750 production of pipe purveyance a diameter 350 mm from the blooms crossing to 370õ440 mm got the Pipe purveyance in a rolling mill 900 for five passage-ways (instead of after 11-13 as a rule on all trubozagotovochnykh figures). Satisfactory makrostruktura of metal is got
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