Monitoring and Prediction of the Liquid Steel Temperature in the Ladle and Tundish

This article is focused on the description of the main features of an online system for the real time monitoring and prediction of the liquid steel temperature in the ladle and tundish. Monitoring and prediction are based on a combination of analytical and statistical methods. Thus e.g., the temperature profiles of the walls are calculated using multi-layer implicit difference scheme taking into account the current temperature of the steel, preheating of the ladle and/or tundish, properties of the refractories, etc. Liquid steel temperatures are calculated from the heat balance of the heat fluxes into the walls and other losses. The influences of all the processes in the secondary metallurgy are taken into account in this system too. The liquid steel temperature prediction is being made continuously during the processing of steel from the LD converter to the continuous casting

Kontrola kvalitete elektroerozijske teksture

This paper deals with quality control of the electro-discharge texturing. Automobile manufacturers have strict requirements for micro-geometry parameters of rolled metal plates from contractors of body sheet metal. The micro-geometry of the roll surface has significant influence on the final quality of the rolled metal plate. In this paper electro-discharge texturing parameters are analyzed, for example, the texturing current, impulse time, technological pause, and their impact to roughness average and peak counts. Quality control is discussed based on mathematical model for estimating the texturing current, impulse time, and technological pause for roughness average or peak counts required value.Rad opisuje kontrolu kvalitete elektroerozijske teksture. Proizvođači automobila postavljaju prema dobavljačima lima za karoserije stroge zahtjeve za parametre mikrogeometrije valjanih limova. Mikrogeometrija valjane površine ima značajan utjecaj na završnu kvalitetu valjanih limova. U ovom su radu analizirani parametri elektrolizijske teksture, npr., jakost struje, trajanje impulsa, tehnološka pauza i utjecaj na prosječnu hrapavost i broj vrhova. Kontrola kvalitete se razmatra na osnovu matematičkog modela za procjenu jakosti struje, trajanja impulsa i tehnološke pauze za zahtjevanu hrapavost i broj vrhova

Kontrola točke staljivanja na aglomeracijskoj traci

The paper describes the control of burn-through point for sinter on the agglomeration belt. This control is based on mathematical modelling of agglomeration process. The mathematical models and algorithms are derived from basic models of physical and chemical processes of agglomeration belt and they are based on directly and indirectly measured quantities of agglomeration belt. The feed-forward control is based on the quantity of the gas combusted in the ignition furnace and on the quantity and composition of the raw mix. This value is corrected according to the identified burn-through point. Output from the control system is the required value of turbo-exhausters operating speed.U radu se opisuje kontrola točke staljivanja sintera na aglomeracijskoj traci. Ta se kontrola zasniva na matematičkom modeliranju aglomeracijskog procesa. Matematički modeli i algoritmi su izvedeni iz temeljnih modela fizičkih i kemijskih procesa na aglomeracijskoj traci i osnivaju se na izravno i neizravno izmjerenim količinama na aglomeracijskoj traci. Kontrola kretanja naprijed se zasniva na količini plina izgorenog u potpalnoj peći i na količini i sastavu sirove mješavine. Ta veličina se ispravlja prema utvrđenoj točki staljivanja. Izlaz iz kontrolnog sustava je tražena vrijednost operativne brzine turbo-puhala

Smanjvanje troškova proizvodnje željeza promjenama parametara vjetra visoke peći

The blast-furnace wind from hot-blast stoves is a significant factor of the blast furnace functioning. The technology was analyzed in which the hot wind from hot-blast stoves is not mixed with the cool wind to a constant wind temperature, but is blown directly into the blast furnace. However, it is necessary to compensate for the changes of the theoretical temperature of burning in blast furnace as a consequence of non-stabilized wind temperature, by changing composition of the wind. This can be done by adding different media into the wind with different results from the operational and economical viewpoints. Essentially, the following types of media are used in blast furnaces: steam, oxygen, substitution fuels, nitrogen, and waste gas.Vjetar visoke peći i peći za zagrijavanje značajno utječe na rad visoke peći. Analizirana je tehnologija kod koje se vrući vjetar iz peći za zagrijavanje ne miješa s hladnim vjetrom do postizanja konstantne temperature nego se direktno upuhuje u visoku peć. Međutim, potrebno je promjenama sastava vjetra kompenzirati promjene teorijske temperature izgaranja u visokoj peći uzrokovane nestabiliziranom temperaturom vjetra. Ovo se može obaviti dodavanjem različitih medija u vjetar uz postizanje različitih rezultata s pogonskog i ekonomskog gledišta. U biti, kod visokih peći se koriste sljedeći mediji: vodena para, kisik, zamjenskog goriva, dušika i otpadnih plinova

Quality control of the electro-discharge texturing

This paper deals with quality control of the electro-discharge texturing. Automobile manufacturers have strict requirements for micro-geometry parameters of rolled metal plates from contractors of body sheet metal. The micro-geometry of the roll surface has significant influence on the final quality of the rolled metal plate. In this paper electro-discharge texturing parameters are analyzed, for example, the texturing current, impulse time, technological pause, and their impact to roughness average and peak counts. Quality control is discussed based on mathematical model for estimating the texturing current, impulse time, and technological pause for roughness average or peak counts required value

Reduction of costs of iron production by changing parameters of the mixed blast-furnace wind

The blast-furnace wind from hot-blast stoves is a significant factor of the blast furnace functioning. The technology was analyzed in which the hot wind from hot-blast stoves is not mixed with the cool wind to a constant wind temperature, but is blown directly into the blast furnace. However, it is necessary to compensate for the changes of the theoretical temperature of burning in blast furnace as a consequence of non-stabilized wind temperature, by changing composition of the wind. This can be done by adding different media into the wind with different results from the operational and economical viewpoints. Essentially, the following types of media are used in blast furnaces: steam, oxygen, substitution fuels, nitrogen, and waste gas

Metode praćenja intenziteta toplinskog toka u stjenci visoke peći

In this paper we present the main features of an online system for real-time monitoring of the bottom part of the blast furnace. Firstly, monitoring concerns the furnace walls and furnace bottom temperatures measurement and their visualization. Secondly, monitored are the heat flows of the furnace walls and furnace bottom. In the case of two measured temperatures, the heat flow is calculated using multi-layer implicit difference scheme and in the case of only one measured temperature, the heat flow is calculated using a method based on application of fractional-order derivatives. Thirdly, monitored is the theoretical temperature of the blast furnace combustion process in the area of tuyeres.U radu se prikazuju osnovna svojstva on-line sustava za praćenje u realnom vremenu donjeg dijela visoke peći. Prvo, praćenje obuhvaća mjerenje temperatura stijenki i dna visoke peći te njihovu vizualizaciju. Drugo, prate se toplinski tokovi na stijenkama i dnu peći. U slučaju dvaput izmjerene temperature, toplinski tok se računa korištenjem višeslojne implicitne sheme diferencije, a u slučaju samo jednom izmjerene temperature, toplinski tok se računa korištenjem metode koja se temelji na primjeni frakcionalnih derivacija. Treće, prati se teoretska temperatra procesa izgaranja u području otvora za zrak