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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Mathematical models in an integrated steel making plant

Rees, C. S. January 1986 (has links)
No description available.
2

The Research of Integrated Steel Company's Overhead Allocation

Lin, Wen-hao 31 May 2005 (has links)
The cost management and control are the important topic that most of enterprise operators have to confront with. Facing the increasing competition in enterprise environment, it is, in active respect, necessary to control the cost effectively in order to gain niche in keen market competition; in positive respect, it is to avoid any error policy decision because of inaccurate cost data. In traditional cost accounting, the allocation method of overhead is incomplete so that it is easier to result a distortion phenomenon in production cost structure. For the past years, the management academic world has proved through detailed study and real application that using the Activity-Based Costing (ABC) System can improve the defect of traditional cost accounting. The reasonable operation analysis and the exact cost driver allocation of ABC System will enhance the accuracy of the cost data. This case study company is a sole integrated steel producer in Taiwan. Due to the diversity of products, the company¡¦s production processes are extremely complicated and varied. The existing cost management system is unable to provide an actual cost under the different processes. Therefore, there is a room for improvement in analyzing the cost sharing of product expenses. This report takes the case study company¡¦s BOF plant as an example to research, by means of the process analysis, how to allocate the cost exactly, and to make a new cost system which can match the spirit of ABC. Meanwhile, this report makes a comparative analysis between the original cost system and ABC one. The result of the research revealed that the ABC cost system may truly improve the phenomenon of distortion of the product cost structure in the case study company. Using ABC cost system may not only promote the accuracy of the cost information, but also enhance the working performance under the activities analysis and control and reduce the waste of resources.
3

Electricity Sector Reform: Sourcing and Cost Management of Electricity for Steel Manufacturing in Nigeria

Okonkwo, Christopher Ndubuisi 01 January 2016 (has links)
In 2014, Lazard levelized cost of energy analysis model priced diesel powered systems at $0.225 – $0.404/KWh and a range of $0.165 – $0.242/KWh for gas-powered systems. The model gave a range of $0.28 – $0.33/kWh for diesel and a range of $0.14/kWh – $0.16/kW for gas fired. Nigeria has an abundance of gas reserves, but heavy gas flaring by oil companies perpetuates power failure across Nigeria. What has resulted is an unreliable electricity infrastructure and a high cost of alternative energy. The Electricity Power Sector Reform Act of 2005 started the reform process. Guided by decision theory, the purpose of this multiple case study was to understand the perceptions of business leaders at the steel manufacturing businesses on how the use of multiple supply sources of electricity might lead to survival, growth, and profitability. The study’s population consisted of 10 steel manufacturing companies in the Southwest region of Nigeria. The data were collected via semistructured interviews with the leaders who source energy, a review of archival records, and observations of company officials placing orders from multiple sources. The van Kaam method of data analysis generated 5 themes: cost of generating electricity and the investment in alternative sources of energy, erratic power supply and its impact on the steel production industry, quality of power supply relative to the capacity and its impact on profits, electricity factor in the steel production process, and use of multiple sources. These findings may contribute to social change by increasing employment opportunities for members of the local community, who will have an enhanced understanding about steel and seize entrepreneurial opportunities.
4

Strategic and operational capabilities in steel production : Product variety and performance

Storck, Joakim January 2009 (has links)
Steel producers that employ niche market strategies are continuously seeking to reduce production cost while maintaining adiverse product mix. The business model is typically based onmarketing of high–strength special or stainless steels. However,the desire to avoid direct cost competition is over time gradually leading towards increased product variety and smaller ordervolumes (tonnes per order) for each product. This thesis analyses how production cost is linked to productvariety in steel strip production. Results are based on new modelsfor assessment of opportunities for performance improvement inhigh product–variety steel production. The need for flexible production processes increases with increasing product variety. Operational capabilities linked to processflexibility determine the extent to which steel producers caneliminate in–process inventory and accomplish close coupling between process steps. Niche market producers that invest inprocess flexibility improvements can lower production costs bothdue to reduced work–in–process and lower energy consumption.An additional benefit is reduced environmental impact. The following problems are addressed: • Development of a method to assess the influence of productvariety on performance in steel production. • Development of models of continuous casting and hotrolling that account for product variety and cost effectswith consideration of varying degrees of process flexibility. • Development of a strategy process model that focus on thestrategic value of operational capabilities related to processflexibility. Investments in operational capabilities regarding process flexibility have a strategic impact. An appreciation for the effectsof process flexibility should permeate the organisation’s daily work since the accumulated contribution of many, seemingly unimportant, incremental changes significantly influences thestrategic opportunities of the company. / Stålproducenter med nischmarknadsstrategier försöker ständigt sänka sina produktionskostnader samtidigt som en varierad produktflora bibehålls. Affärsmodellen bygger i typfallet på försäljning av höghållfasta specialstål eller rostfria stål. Strävan att undvika direkt priskonkurrens leder dock med tiden gradvis till ökad produktvariation och mindre ordervolymer (ton per order)för varje produkt. Denna avhandling analyserar hur produktionskostnaden är kopplad till graden av produktvariation vid tillverkning av band.Resultaten bygger på nya modeller för utvärdering av förutsättningarnaför prestandaförbättring i stålindustri med stor produktvariation. Behovet av flexibla produktionsprocesser ökar med ökande produktvariation. Praktiska förmågor kopplade till processflexibilitet avgör till vilken grad ståltillverkare förmår att eliminera mellanlager och åstadkomma en tät koppling mellan processteg.Nischmarknadsproducenter som investerar i förbättrad flexibilitet kan sänka sina produktionskostnader både genom minskad mängd produkter i arbete och reducerad energiförbrukning. Detta medför också minskad miljöbelastning.Följande problemställningar adresseras: • Utveckling av en metod för att utvärdera inverkan av produktvariationpå prestanda vid ståltillverkning. • Utveckling av en modell för stränggjutning och varmvalsningsom tar hänsyn till produktvariation och kostnadseffekterför olika grad av processflexibilitet. • Utveckling av en strategimodell som fokuserar på det strategiskavärdet av operativa förmågor kopplade till processflexibilitet. Investeringar i operativa förmågor vad avser processflexibilitet är av strategisk betydelse. Förståelse för betydelsen av processflexibilitetbör genomsyra det dagliga arbetet eftersom det samladebidraget av många, till synes obetydliga, små förändringar haren avgörande inverkan på företagets strategiska förutsättningar / QC 20100810
5

Comparison Of Sub-processes And Final Products Of Iron And Steel Production With Life Cycle Assessment

Olmez, Gulnur 01 December 2011 (has links) (PDF)
Iron and steel production is one of the most resource and energy demanding industries around the world. Throughout the life cycle of iron and steel products, the intensive use of raw materials and energy results in contributions to a wide range of environmental impacts. This study conducts a life cycle assessment (LCA) for iron and steel production in Turkey using SimaPro software and IMPACT 2002+ impact assessment method with the purpose of comparing the impacts of life cycle stage (coke making, sintering, iron making, steel making) and final products (billet, slab, hot rolled wire rod, hot rolled coil). The system boundary was set as cradle-to-gate, the functional unit was selected as 1 ton of product, and the study was conducted using the inventory data collected from one of the three integrated iron and steel facilities representing the majority of the industry in Turkey. Different production scenarios for the final products were also evaluated to see the variation in the total impacts. The results indicated that, liquid steel production process exhibited the highest total environmental impact, which was followed by sinter production. Coke production process showed the highest impact on depletion of non-renewable energy sources. The comparison of the impacts for different final products revealed that hot rolled coil causes the highest total environmental impact. Moreover, the environmental impact of mechanical workshop of the facility was found negligible when compared to the production processes.
6

Cost Management System for Integrated Steel Production¢wA Case Study for China Steel Corporation

Luo, Chia-Wen 22 June 2002 (has links)
It is a critical issue for enterprises to manipulate the competitive strategy, cost control, and increase ability in the intensive competition. The major duty of cost management is how to offer data or information that are truly needed for their managers, and how to present data or information on time, reasonable, or correct. In order to understand the cost management is satisfaction to its management decision or not, and what is its really need on cost management of target enterprise. This research adopted interview method which were given to each level managers and also try to access related information to prove the really requirement of cost management. In this research, we computed the detailed product cost of target enterprise, and analyzed these figures under the basis of Standard Product Cost and actual cost. We found there were 474 categories included in this company of its norm of product item of F10 category. Furthermore, according to the cost data that showed on its financial report when we compared the cost of the detailed product norm, we found that the lowest was 92.92% below the average cost and the highest was 154.27% above the average cost. There is obvious difference between the lowest and the highest cost; therefore, as an information provider, he or she has the obligation to frankly express related data to managers and help them to make a correct decision. The case company currently applies Standard Product Cost system as its cost system. However, it is not alike traditional cost system, there are some similar with Activity Base Cost system. In this dissertation, we will modify or add some cost data and procedure of cost process under current cost system. After modification cost system, we attempted to calculate reasonable detailed product cost base on actual cost. Fortunately, when we combined the modification cost system and order system of the target enterprises, we discovered some results and those help us to realize cost information of customer and appraise the contribution of each sales order or every customer. To do so, we can provide the calculation of performance of product cost and exploitation efficiency of new product, before and after of quality improvement of each product. Finally, the modification cost system also can be used as reference for sales pricing and profit planning of combination production-sale system.
7

Analysis of the electrochemical processes during the production of liquid iron by Molten Oxide Electrolysis / Analyse de processus électrochimiques lors de la production de fer liquide par l’électrolyse à l’oxyde fondu

Wiencke, Jan-Christian 20 December 2017 (has links)
L'électrolyse en milieu oxydes fondus (MOE) peut être envisagée comme une nouvelle technologie de l’industrie sidérurgique pour la production de fer liquide sans émission de CO2. Dans ce concept, l'électrolyse est utilisée pour produire de l’oxygène gazeux et du fer liquide à des températures supérieures à 1810 K. Dans cette étude sont présentées les principales réactions électrochimiques lors de l’électrolyse en milieu fondu (MgO-Al2O3-SiO2). Une quantité importante de fer liquide a été produite lors d'électrolyses conduites pendant plusieurs heures. L'analyse MEB-EDS du dépôt a révélé un alliage de fer métallique quasi pur, uniquement contaminé par le matériau cathodique. Ce résultat traduit une sélectivité élevée du procédé électrolytique. L'étude de la réponse de l'électrolyte en fonction de la tension électrique et de la concentration de fer a révélé une limitation par la diffusion lors de l’électrolyse de bains de faibles concentrations en oxyde de fer, et à des potentiels inférieurs à 1,5 V. La demi-réaction de la cathode a été identifiée comme la réduction du fer ferreux en fer métallique. L’extrapolation des droites de Tafel sur les courbes courant-tension corrigées de la chute ohmique a conduit à des coefficients de transfert (de la réaction cathodique) proches à 0,6. L’ordre de réaction de réduction de FeII en Fe0 a été évalué autour de 1. L'analyse de la demi-réaction anodique dans les oxydes fondus à faible teneur en fer a montré que les premières espèces éctroactives sont les anions oxydes libres. Pour des tensions électriques croissantes, le transport des anions O2- libres devient limité et le transfert de charge est partiellement attribué à l’oxydation du fer ferreux. Au contraire, dans des mélanges d’oxydes fondus à concentrations élevées en fer, le transfert de charge est réalisé dans toute la gamme de tension par l'oxydation du fer ferreux. C’est seulement à haute tension, que l’oxydation des anions oxyde contribue au transfert des charges. Dans l'ensemble des compositions testées, aucune limitation du courant n’a été observée sur la réaction anodique / Molten oxide electrolysis (MOE) is an ambitious technique for the production of liquid iron by the use of renewable energies and thus lower CO2 emissions in the steel industry. In this concept, electrolysis is used to produce gaseous O2 and liquid iron metal at temperatures above 1810 K. In the experimental study presented here the key-parameters of the electrochemical reactions in a magnesio-aluminosilicate electrolyte and at the electrodes during MOE are investigated. A significant amount of liquid iron metal was produced during experiments of several hours. SEM-EDS analysis of the deposit revealed an alloy of iron metal and of the cathode material, which thereby indicates high process selectivity. Investigation of the electrolyte’s response in dependence of cell voltage and iron concentration inferred a diffusional limitation at low iron oxide concentrations at potentials below 1.5 V. The cathode half-reaction was identified as the reduction of ferrous iron to liquid iron metal. Using Tafel interpretation reaction-transfer coefficients close to 0.6 and an order of reaction around 1 were determined. The analysis of the anode half-reaction showed that in low iron bearing molten oxides, oxide anions were firstly oxidized into O2 gas. At high iron concentrations the charge transfer is conducted in the entire cell voltage range by the oxidation of ferrous iron. The participation of oxide anions in the charge transfer was only witnessed at high cell voltages. In the entire compositional range a limitation of the measured current due to the anode half reaction was not observed
8

Hydraulisk centrering i vägstålstillverkning vid Olofsfors AB / Hydraulic centering in road steel production at Olofsfors AB

Andersson, Elias January 2022 (has links)
Olofsfors AB är ett företag som tillverkar olika typer av stålprodukter. En av produkterna är deras vägstål, vilket de har tillverkningsproblem med i dagsläget. Råmaterialet i form av plattstång behöver centreras av hydraulcylindrar under transport samt under hålstansningsprocessen. I dagsläget centrerar cylindrarna inte materialet på ett korrektsätt. I detta arbete har brister i det nuvarande systemet undersökts och förslag till förbättringar för det hydrauliska centreringssystemet tagits fram. Syftet med arbetet var att få en bättre funktion för centreringen av plattstång ivägstålsproduktionen, samt att möjliggöra en kortare cykeltid. För att hitta problem i nuvarande system studerades hydraulschemat. När misstankar om en dålig systemdesign uppstod, användes ett program som heter FluidSim 5 för att simulera och validera misstankarna. En slutsats som kunde dras var att det nuvarande hydrauliska systemet inte kan garantera en tillförlitlig centrering av råmaterialet. Lösningsförslaget som tagits fram innefattar en roterande flödesdelare med ett säkerhetssystem för tryckintensifiering och kavitation. Om en flödesdelare med 2% delningsnoggrannhet används, blir centreringsnoggrannheten runt 1—2 mm, beroende på vilka cylindrar som studeras. Då en flödesdelare används, är noggrannheten hos cylindrarna starkt beroende av den aktiva slaglängden. När slaglängden minskas uppnås snävare toleranser hos centreringen. / Olofsfors AB is a company that manufactures different steel products. For one of their products, road grading steel, they currently experience problems in the manufacturing process. The raw material in the form of flat bars needs to be centered by hydraulic cylinders during transport and during hole punching. In the current situation, thecylinders do not center the material in a correct way. In this report, functional errors are identified and improvements in the hydraulic centering system are proposed. The purpose of this study was to improve centering of the flat bar for road grading steel production, and to enable a shorter cycle time. To identify problems in the existing system, the hydraulic scheme was studied. When suspicions of a poor system design arose, a program called FluidSim 5 was used to simulate and validate the suspicions. One conclusion that could be drawn was that thecurrent hydraulic system could not guarantee a reliable centering of the raw material. The proposed solution comprises a gear type flow divider, with a safety system for pressure intensification and cavitation. Using a flow divider with 2% dividing accuracy, the centering accuracy is around 1—2 mm, depending on the cylinders selected. When using a flow divider, the accuracy of the cylinders is strongly dependent of the active stroke length. When the stroke length is reduced, tighter tolerances are achieved in the centering.
9

Getting a Grip on Scrap : Applying Probability and Statistics in Analyzing Scrap and Steel Composition Data from Electrical Steel Production

Seyedali, Seyed Mohamad January 2013 (has links)
This study intends to better control the final composition of steel by trying to have a better knowledge of elements including copper, nickel, molybdenum, manganese, tin and chromium in the scrap. This objective was approached by applying probability and statistical concepts such as normal distribution, multiple linear regression and least square and non-negative least square concepts. The study was performed on the raw materials’ information of Ovako Smedjebacken and Ovako Hofors, two steel production plants in Sweden. The information included but were not limited to the amount of the different scrap types used in the charge, total weight of the charge and the final composition of the produced steel.  First, the concept of normal distribution was used as to consider the variations of the alloying elements between the estimated and measured alloy contents. The data were then used to consider a model for distribution factor of the studied elements. Also, an estimation of the alloy contents in the scrap type given the final steel composition was carried out using the concept of probability and statistics. At the end, a comparison of the results from the different concepts was done.
10

Dynamic Scheduling of Steel Casting and Milling using Multi-agents

Cowling, Peter I., Ouelhadj, D., Petrovic, S. 13 July 2009 (has links)
No / This paper presents a case study on the use of multi-agents for integrated dynamic scheduling of steel milling and casting. Steel production is an extremely complex problem requiring the consideration of several different constraints and objectives of a range of processes in a dynamic environment. Most research in steel production scheduling considers static scheduling of processes in isolation. In contrast to earlier approaches, the multi-agent architecture proposed consists of a set of heterogeneous agents which integrate and optimize a range of scheduling objectives related to different processes of steel production, and can adapt to changes in the environment while still achieving overall system goals. Each agent embodies its own scheduling model and realizes its local predictive-reactive schedule taking into account local objectives, real-time information and information received from other agents. Agents cooperate in order to find a globally good schedule, which is able to effectively react to real-time disruptions, and to optimize the original production goals whilst minimising disruption carried by unexpected events occurring in real-time. The inter-agent cooperation is based on the Contract Net Protocol with commitment

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