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NOVÁ EXPERIMENTÁLNÍ POLOPROVOZNÍ METALURGICKÁ VÝZKUMNÁ LABORATOŘ BUDOVÁNA VE SPOLEČNOSTI MMV V RÁMCI PROJEKTU RMTVC NEW EXPERIMENTAL PILOT PLANT METALLURGICAL LABORATORY BUILT IN THE COMPANY MMR, WITHIN THE RESEARCH PROJECT RMTRC Vladislav KURKA a, Jaroslav PINDOR b, Karel MICHALEK
c
a MATERIÁLOVÝ A METALURGICKÝ VÝZKUM s.r.o. Pohraniční 639/31, 70602 Ostrava-Vítkovice, Česká republika,
[email protected] b MATERIÁLOVÝ A METALURGICKÝ VÝZKUM s.r.o. Pohraniční 639/31, 70602 Ostrava-Vítkovice, Česká republika,
[email protected] c Vysoká škola báňská - Technická univerzita Ostrava, 17.listopadu 15/2172, 708 33, Ostrava-Poruba, Česká republika,
[email protected]
Abstrakt Tato práce se zabývá popisem návrhu a budování laboratoře „Laboratoř pro experimentální ověřování technologií výroby nových materiálů“, jejíž výstavba je realizována v rámci projektu „Regionální materiálově technologické výzkumné centrum“ č.: CZ.1.05/2.1.00/01.0040, potažmo výzkumným programem č. 6 s názvem „Experimentální ověřování nových technologických postupů u kovových materiálů s vyššími kvalitativními parametry“. Laboratoř posílí metalurgickou základnu společnosti MATERIÁLOVÝ A METALURGICKÝ VÝZKUM s.r.o. s cílem sofistikovanějšího výzkumu a vývoje metalurgických procesů. Pro budování laboratoře bude využito současné zařízení „Vakuová a přetlaková indukční tavící pec“ (dále jen VPIM), jež projde rozsáhlou modernizací. Modernizované zařízení VPIM bude mít vyšší účinnost vakuovacího systému. Dále bude možné měřit on-line teplotu taveniny v průběhu celého metalurgického procesu. Pro možnost odlévání ocelové taveniny do různých typů a počtů ingotů, v navolené atmosféře a tlaku, je navržen odlévací keson s rafinačním žlabem. Pro zvýšení reakční účinnosti strusky a implementace kyslíkových pochodů bude zařízení disponovat kyslíkovou tryskou. Řízení metalurgických pochodů odplynění a oxidace bude prováděno za pomoci analyzátoru plynů v atmosféře kesonu: vodíku, oxidu uhličitého a oxidu uhelnatého. Programování, archivace a vyhodnocení dat bude realizováno až po implementaci konstrukčních celků a oživení celého systému. Inovované zařízení VPIM bude sloužit pro výzkum a vývoj technologií výroby vysoce jakostních ocelových a kovových materiálů. Metalurgické procesy tavení, rafinace, legování a oxidace bude možno provádět v podmínkách sníženého tlaku (vakua) nebo za přetlaku inertní atmosféry argonu nebo dusíku. Klíčová slova: ocel, kovové materiály, vakuum, přetlak, argon, dusík, indukční tavící pec.
Abstract The work describes the proposal and construction of new “Laboratory for experimental verification of technologies for production of new materials“ realized within the project „Regional Material Technology Research Center“ (hereinafter RMTRC) No. CZ.1.05/2.1.00/01.0040, research program No. 6 named „Experimental verification of new technological processes for metallic materials with higher qualitative parameters“. The research laboratory will strengthen metallurgical research in the company MATERIAL AND METALLURGICAL RESEARCH Ltd., the main aim is sophisticated research and development of metallurgical processes. New laboratory will use the existing unit “Vacuum and over-Pressure Induction Melting Furnace” (hereinafter VPIM),which will be extensively modernized. The upgraded VPIM will have higher efficiency of the vacuum system. Moreover, the melt temperature during melting process will be measured on-line. Casting chamber has been designed for the possibility of casting of molten steel
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into different types and numbers of ingots under selected atmosphere and pressure. The unit will have an oxygen jet in order to increase the efficiency of reaction of slag and to enable oxygen processes. Metallurgical processes of degassing and oxidation will be controlled by using the gas analyzer for the gases used in the atmosphere of the chamber (hydrogen, carbon dioxide and carbon monoxide). Programming, archiving and data analyses will be programmed after the implementation of structural units and putting of the whole system into operation. The innovated unit VPIM will serve for research and development of production technologies for high quality steels and metallic materials. Metallurgical processes of smelting, refining, alloying and oxidation can be carried out under conditions of reduced pressure (vacuum) or overpressure of inert atmosphere of argon or nitrogen. Key words: steel, metallic materials, Vacuum and Pressure Induction Melting Furnace, argon, nitrogen, vacuum
INTRODUCTION The company MATERIAL & METALLURGICAL RESEARCH Ltd. (hereinafter MMR) built a unit named “Vacuum and over-Pressure Induction Melting furnace" (hereinafter VPIM), within the frame of the project of the Ministry of Education No. MSM 2587080701. At present the VPIM makes a part of the “Laboratory for experimental verification of technologies for production of new materials”, which is being constructed under the project "Regional Material Technology Research Centre”, No. CZ.1.05/2.1.00/01.0040 (hereinafter RMTRC). It is generally true that if research-development laboratories are to solve the issues for productiveindustrial practice, it is imperative that their output parameters are approx. by one order better. Modifications of the VPIM are concentrated on several key points. For the purposes of research and development of new technologies for production of new metallic materials it is necessary to ensure casting of various types of ingots, not only by “top pouring” (present state), but newly also by “bottom pouring”. The required decarburization, degassing and deoxidation of the melt requires an efficient vacuum system, which is capable to maintain the minimum pressure in the “Vacuum and Pressure chamber” (hereinafter VP Chamber) even at evolution of gases from metallurgical process. The melt will be maintained at the required temperature by induction heating and its temperature will be checked by on-line optical two-colour pyrometer. In order to attain higher degree of removal of carbon an oxygen-argon nozzle will be implemented into VPIM with possible selection of mutual proportion of gases from 0 to 100%. Small metallurgical units (e.g. laboratory electric arc furnaces or oxygen converters) in comparison with traditional industrial units have large heat losses, mainly through the walls of the furnace. Generally speaking disadvantage of induction melting furnaces consists in low temperature of slag, which subsequently participates in minimal extent in metallurgical processes. Slag modes in induction furnaces are only partially transferable to the secondary metallurgy unit. For this reason the O2/Ar nozzle will be installed and induction will be used for heating. 1.
CURRENT STATE OF VPIM
This chapter briefly presents the basic "label" parameters of VPIM and its integral components:
Electric melting power
600 kW;
Weight of molten metal
1750 kg;
Frequency of inductor
1000 Hz;
Voltage
2000 V;
Blowing blocks under rammed lining
Ar: 1-50 Nl.min-1, N: 2,4-120 Nl.min-1;
Dimensions of melting crucible
diameter 610 mm, height 1000 mm;
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Volume of melting crucible
0,245 m3;
Volume of VP chamber
26,4 m3;
Diameter of VP chamber
3000 mm;
Height of VP chamber with a cover
4250 mm;
Working vacuum
50 Pa (0,5 mbar) abs.;
Working pressure (argon or nitrogen)
0,5 MPa (5 bar) abs.;
Maximum height of ingot mould set
2800 mm.
2.
MODERNIZATION OF VPIM
Modernization of the VPIM is divided into several basic parts, which will be realised as one unit. These are:
Equipments for technological operations. The VPIM must be adapted to new technological operations involving the preparation, processing and casting of molten metal (oxygen nozzle, correction of chemical composition, metal sampling, single-shot and on-line measurement of temperature, innovative connection of VPIM to the supply of argon and nitrogen, and new software for tracking, controlling, archiving and analysing of data from VPIM.
Equipments for technology of “bottom” pouring. It is necessary to ensure the so-called bottom pouring into different types and quantities of ingots, which is a guarantee for achieving the desired surface and internal quality parameters of the material. This is a fundamental condition for further technological and technical operations leading to a certain type of product, on which it would be therefore possible to study the material properties.
On-line analyzers of the process gases and temperature measurement. It is absolutely necessary to know the course of evolution of process gases in dependence on the temperature of molten metal for study of the kinetics of the process of use of vacuum. For this reason, the VPIM will be equipped with the on-line measurement of the process gases (H2, CO and CO2) and with measurement of the temperature of the melt and of solid charge.
Up-grade the vacuum and over-pressure system. Study of the influence of "depth" of vacuum for degassing of molten material and for decarburization process requires assurance of lower values than those commonly used in industrial units. Enhancement of the vacuum station in order to achieve its higher performance (deeper under-pressure) will be realized on condition of an increase of the volume of VP chamber. The possibility of over-pressure of nitrogen (for study nitrogenation) and argon (as inert gas) will be maintained.
Additional equipments. It is needed in view of the integrity of the VPIM unit and it includes provision of the following: work place for VPIM unit, workplace for preparation of casting and assurance of necessary equipment and components required for casting (stools, ingot moulds, sprue pins, tundish, refractory material, equipment for separation of slag from the molten metal, fixtures and equipment for preparation of the casting).
Possible new form of VPIM is shown in fig. 1, which was designed by the companies MMR and PROVITAS. For the bottom pouring it was proposed to build a new "pouring caisson”. Molten metal is cast from the induction melting furnace into the tundish, in which it is refined by flowing through ceramic filters. The tundish is drawn only schematically, its size and slope will be finalized in the next stage of the solution. The melt in the tundish is poured from the "melting chamber" into the "pouring caisson", from which it is cast into the prepared set of ingot moulds. The installed oxygen/argon nozzle will serve for study of the metallurgical processes of decarburization and oxidation of the melt.
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Oxygen – Argon Nozzle
Two-colour pyrometer
Melting “Vacuum Pressure chamber” “Pouring chamber”
Induction melting furnace
Tundish
Ingot mould
Fig. 1. Proposal of a new design of the unit “Vacuum and over-Pressure Induction Melting furnace”. It was designed by the companies MATERIAL AND METALLURGICAL RESEARCH Ltd. and PROVITAS SpA for possibility of melting, refining and bottom pouring of metallic melt Modernized VPIM is being built for research and development of technologies for production of steel melts in large metallurgical aggregates. The VPIM will be able to simulate selected metallurgical operations of the following metallurgical units:
Primary metallurgy unit: BOF - Basic Oxygen Furnace. Beyond the frame of the project, within which the work is carried out, the author has an idea of how to modify the VPIM unit, so that it will make it possible to simulate metallurgical processes of EAF - Electric Arc Furnace.
Secondary metallurgy unit: VD - Vacuum Degassing and parts of the process of the ISSM unit Integrated System of Secondary Metallurgy, LF - Ladle Furnace, RH-OB - Ruhrstahl Heraeus-Oxygen Blowing.
Processes of the metallurgical units: AOD - Argon Oxygen Decarburization, VOD - Vacuum Oxygen Decarburization, VCD - Vacuum Carbon Deoxidation and metallurgical processes using low pressure or over-pressure of argon or nitrogen.
VPIM unit will also allow to control of purity of metallic melt during its pouring with use of the installed ceramic filters.
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CONCLUSION This article describes the current parameters of the unit "Vacuum and over-Pressure Induction Melting furnace", called VPIM. The VPIM equipment was included into the concept of building of the "Laboratory for experimental verification of technologies for production of new materials”. As it already follows from the name of the laboratory, the VPIM after its modernization will serve to research and development of production of new metallic materials, technological processes for production of molten steel and its casting. The project comprises also a design of modernization of the VPIM both from the viewpoints of its construction and metallurgy. The paper also outlines, which metallurgical unit and metallurgical processes may be simulated by the VPIM. LITERATURE [1.]
KURKA, V. Research and Development of Technology for Production of High-alloyed Chromium Steels with Low Contents of Oxygen and Carbon and High Content of Nitrogen. Hutnické listy, 2009, Vol. LXII, No. 5, p. 42-46, ISSN 0018-8069.
[2.]
KURKA, V., KRATOCHVÍL, I., KRAYZEL, M., MRÁČEK, J. Steel Refining in Induction Furnace by Pressure, In European Electric steelmaking conference. Poland, Krakow. Institute of Metallurgy, Polish Academy of Sciences: 2008 p. 547-549, ISSN 1733-3490.
[3.]
KURKA, V. Research, Development and Verification of New Technologies of Refining of the Molten Steel in Vacuum and Pressurized Induction Melting Furnace. Hutnické listy, 2010, Vol. LXIII, No. 5, ISSN 0018-8069.
[4.]
Regionální materiálově technologické výzkumné centrum - vydání Rozhodnutí o poskytnutí dotace, Ostrava: 22.2.2010. [cit. 10.10.2010]. Accessible from www
.
[5.]
Regionální materiálově technologické výzkumné centrum. [cit. 10.10. 2010]. Accessible from www: .
ACKNOWLEDGEMENTS The authors are grateful for the support of experimental works by the project of the Ministry of Education, youth and sports and European Union No. CZ.1.05/2.1.00/01.0040
