Дисертації з теми "Steel wire rod"

The concept of microstractural engineering has been applied to Stelmor cooling of steel wire rod. The Stelmor process is situated immediately following the rod mill and utilizes forced air to cool steel rod from the rolling temperature, through austenite transformation, down to a temperature suitable for handling. A mathematical model has been developed for the prediction of the mechanical properties of the steel rod as a function of cooling parameters in the process and steel composition. The model is based on one-dimensional heat conduction within the rod and is limited to plain-carbon eutectoid and hypoeutectoid steels. Phase transformation kinetics in the model, for both the austenite-ferrite and austenite-pearlite reactions, have been characterized through the use of the Avrami equation. A combination of experimental and literature data have been employed for the development of equations to quantitatively predict the microstructure formed in the steel rod after transformation. A modified Gladman equation was adopted for the strength predictions. Validation of the model has been achieved with controlled cooling experiments conducted in the laboratory. The experiments were designed to simulate the Stelmor process, involving a range of steel grades, rod diameters and air velocities. Thermal histories in steel rod samples during forced air cooling were acquired by mounting a thermocouple at the centreline of each rod. After cooling, the rod samples were subjected to microstructural examination and mechanical testing. Results from this investigation were utilized to develop relationships among steel composition, thermal history and ferrite fraction, ferrite grain diameter and pearlite interlamellar spacing. The laboratory data was also utilized to modify the strength predictions of the Gladman equation. In order to obtain information on cooling conditions in an industrial setting, a series of experiments has been conducted on an operating Stelmor line at the No. 2 Rod Mill of Stelco Hilton Works. The technique followed in the plant trials was similar to that employed in the laboratory and the thermal histories of the test rods allowed the mathematical model to be "tuned" to operating conditions. Mechanical properties for several industrial steel grades were also measured during the plant trials, and have been applied to test the predictive capability of the model. Comparisons of the model-predicted thermal histories, microstructures and mechanical properties with those measured in both the laboratory and plant tests have been made. The results of the thermal history comparison for both laboratory and plant conditions showed good agreement between the model-predicted and measured centreline temperatures of control-cooled steel rod. Predicted temperatures during the austenite-ferrite and austenite-pearlite phase transformations were within the expected error associated with prediction of transformation kinetics. Good agreement was obtained between model-predicted and measured ferrite fraction, ferrite grain diameter and interlamellar pearlite spacing. Yield strengths and ultimate tensile strengths predicted by the model for the laboratory and plant tests displayed excellent agreement with measured strengths. In order to obtain a test of the predictive capability of the model under Stelmor line conditions, an independent set of ultimate tensile strengths for Stelmor-cooled steel grades was obtained. These samples were taken directly from grades being processed on the line. A comparison between model-predicted and measured UTS for these grades yielded excellent agreement in the 1020-1040 and eutectoid composition range, with a fair prediction obtained for 1055-1065 grades.
Applied Science, Faculty of
Materials Engineering, Department of
Graduate

A comprehensive methodology to physically and numerically model upsetting in cold heading was developed.
The physical model was a Drop Weight Test with a guided pocket-die set capable of approximating industrial cold heading conditions. The results show that the test is sensitive to the critical parameters for cold heading. These include surface quality, residual element level, nitrogen content, microstructure, decarburization, and specimen geometry. The test is capable of assessing the fracture behavior of cold heading materials.
One goal of the study was to reveal differences in fracture behavior with varying steel sources. Accordingly, the matrix of test materials consisted of grade 1038 steels from three different steel sources.
Material preparation and conditioning of test materials approximated industrial procedures for cold heading materials. These procedures included hot rolling, controlled rod cooling, descaling, straightening, lime coating and lubricating, and wire drawing. Spheroidization of test specimens was performed in an industrial batch furnace using an industrial heat treatment cycle.
A finite element program (FEM) enabled the simulation of upsetting in cold heading. The inputs required to model the cold heading process include flow stress behavior and friction conditions representative of cold heading. These inputs were obtained using the CANMET Cam Plastometer and the Friction Ring Test.
The Cockcroft and Latham fracture constants for an as-rolled and a spheroidize annealed 1038 material were computed by FEM modeling and the critical values were calibrated using the Drop Weight Test. The fracture criterion constant was found to be independent of strain path for upsetting in cold heading and thus is material-related.

Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. Thus, it is very important to study the formation and evolution of defects during wire rod rolling in order to better understand and minimize the problem, at the same time improving quality of the wire rods and reducing production costs. The present work is focused on the evolution of artificial defects during rolling. Longitudinal surface defects are studied during shape rolling of an AISI M2 high speed steel and a longitudinal central inner defect is studied in an AISI 304L austenitic stainless steel during ultra-high-speed wire rod rolling. Experimental studies are carried out by rolling short rods prepared with arteficial defects. The evolution of the defects is characterised and compared to numerical analyses. The comparison shows that surface defects generally reduce quicker in the experiments than predicted by the simulations whereas a good agreement is generally obtained for the central defect.

The report examines the factors which may be a contributing cause to the problems that are present when ferritic stainless steel are eddy current tested in a warm condition. The work is carried out at Fagersta Stainless AB in Fagersta which manufactures stainless steel wire. In the rolling mill there is an eddy current equipment for detection of surface defects on the wire. The ferritic stainless steels cause a noise when testing and this noise complicates the detection of defects.Because of this, a study was made of how the noise related to factors such as steel grade, temperature, size and velocity. By observing the signal and with the possibilities to change the equipment settings the capability to let a signal filter reduce the noise level were evaluated. Theories about the material's physical properties have also been included, mainly the magnetic properties, electrical conductivity and the material's tendency to oxidize.Results from the tests show that a number of factors do not affect the inductive test significantly and to use a filter to reduce the noise level does not seem to be a viable option. The level of noise does not relate to the presence of superficial particles in form of oxides.The ferritic stainless steels showed some difference in noise level. Which noise level there was did match well with the steels probability for a precipitation of a second phase, and precipitation of austenite may in this case contribute to noise when using an eddy current instrument.The noise is probably due to some physical material property that varies within the thread.

Луценко, В.А. Наукові основи вдосконаленнятермомеханічної обробки катанки для сталевого дроту малого діаметру [Текст]: дис. … докт. техн. наук: 05.16.01 : захищена ....: затверджена…. /Луценко Владислав Анатолійович. – Запоріжжя, 2015. – 353 с.
UK: Дисертаційна робота присвячена підвищенню в процесі ТМО пластичних властивостей сталевої катанки. Отримана сталева катанка має структуру: високовуглецева – дисперсний перліт із відсутністю замкнутої цементитної сітки, мінімальний зневуглецьований шар, який рівномірно розподілений по периметру; низьковуглецева – рівномірну структуру фериту з мінімальною кількістю перліту; легована – наявність бейніто-мартенситних ділянок до 10% в змішаній структурі. Результати використані на дротових станах ВАТ «БМЗ» та ПАТ «АрселорМіттал Кривий Ріг». Підвищення пластичності катанки забезпечило виготовлення сталевого дроту малого діаметру без проміжної термічної обробки, що дозволило знизити видатковий коефіцієнт металу в середньому на 10%. EN: The dissertation is devoted of increasing in thermo-mechanical processing the plastic properties of steel wire rod. The obtained steel wire rod has the structure: high carbon – the dispersion of perlite without closed cementite net, the minimum depth of equable decarburized layer; low carbon – uniform structure of ferrite with a minimum of perlite; alloy – the occurrence of bainite-martensite areas up to 10% in the mixed structure. The results were used on the rod mills OJSC “Byelorussian steel works” and РJSC “ArcelorMittalKryvyiRih“. The increasing of plasticity provided the production of steel wire of small diameter without intermediate heat treatment, thus reducing the expenditure coefficient of metal by 10% in average. RU: В диссертационной работе решена актуальная научно-техническая проблема – повышение после высокотемпературной прокатки пластических свойств металла путем развития научных основ о влиянии процессов ТМО на структурообразование и качественные характеристики стальной катанки. Установленные закономерности позволили совершенствовать технологию ТМО катанки и при экономии материальных ресурсов обеспечить производство стальной проволоки малого диаметра для металлокорда (в том числе сверхвысокопрочного), высокопрочной бортовой, канатной, легированной сварочной и низкоуглеродистой. Изучена кинетика превращения аустенита непрерывнолитой стали 90 при непрерывном охлаждении и в изотермических условиях. Установлено, что выделения цементита по границам зерен подавляются и полностью отсутствуют при скоростях более 10°С/с и при изотермическом распаде. Определено, что величина эффекта рекалесценции в стали 90 зависит от времени превращения. Установлено, что при ТМО снижение температуры после горячей деформации с 1050…1100°С до 900…950°С в результате принудительного охлаждения при повышении дробности деформации (на 20%) приводит к увеличению пластических свойств высокоуглеродистой стали. Полученная катанка для стальной проволоки, в отличие от традиционной, имеет повышенные пластические свойства. Основу структуры катанки составляет: высокоуглеродистой – сорбитообразный перлит (более 70%) с отсутствием избыточных структур (замкнутой цементитной сетки), минимальный обезуглероженный слой равномерно распределен по периметру; низкоуглеродистой – равномерная структура феррита с минимальным количеством пластинчатого перлита; легированной – наличие бейнито-мартенситных участков до 10% в смешанной структуре. Повышены требования к микроструктуре и свойствам высокоуглеродистой катанки и проволоки, которые отражены в изменении №11 к ЗТУ 840-03-2006 «Катанка стальная сорбитизированная для металлокорда, бортовой проволоки и проволоки для рукавов высокого давления» и ТУ У 276.3-23365425-638.2008 «Проволока стальная термически обработанная». Результаты использованы на ПАО «АрселорМиттал Кривой Рог» при разработке СТИ 228-112-2008 «Производство катанки из легированных сталей для сварочной проволоки ответственного назначения», изменения №3 к режимам охлаждения проката в потоке проволочного стана 150-1 СПЦ-1. Разработаны и внедрены на ОАО «БМЗ» режимы ТМО стальной катанки, в том числе для сверхвысокопрочной проволоки и металлокордапо ЗТУ 840-03-2006 (Изменения к ТК 840-П13-01-2002 и ТК 840-П3-01-2007 на режимы двухстадийного охлаждения катанки различного марочного сортамента в потоке стана 150). Повышение пластичности после высокотемпературной прокатки обеспечило изготовление стальной проволоки малого диаметра различного назначения без промежуточной термической обработки с сохранением требуемых конечных характеристик. Катанка, изготовленная по новому режиму ТМО, переработанная на проволоку малого диаметра, имеет лучшую технологичность в сравнении с базовой. Так, при производстве высокопрочногометаллокорда обрывность снизилась на 34%, а сверхвысокопрочного – на 23%. Освоение усовершенствованных режимов ТМО позволило снизить расходный коэффициент металла в среднем на 10%. Общий фактический экономический эффект от внедренных новых технологических решений составляет 31,7 миллиона гривен, доля автора – 4,44 миллиона гривен.

Additive manufacturing has gained worldwide popularity due to its numerous benefits, which includes structural efficiency, reduction of material consumption and wastage, enhanced customisation, improved accuracy and safety on-site. Among the various categories of the additive manufacturing process, Wire and arc additive manufacturing (WAAM) has proven its ability of producing medium to large scale components. However, there is still a lack of knowledge regarding the structural response and mechanical properties of WAAM-produced elements. This paper provides results of numerical and experimental studies on WAAM rods produces using a commercial ER308LSi stainless steel welding wire. The aim is to evaluate the effect of initial imperfections and material mechanical properties on the response of such rods under compression. Tensile and compression tests were carried out in order to determine the mechanical properties of the rods. Subsequently, numerical simulations were performed in order to simulate the mechanical response of the rods under different conditions.

The aim of the master´s thesis is to analyze the types of road restraint systems, a description of testing road restraint systems and the use of wire rope safety fence in the Czech Republic and abroad. In addition, there is an analysis on the highway of R48 in the section Nový Jičín – Příbor and assessed in terms of the number and type of accidents in connection with wire rope safety fence.

碩士
高苑科技大學
機械與自動化工程研究所
100
Fastener industry is very important in the domestic metal manufacturing industries. Billet-cutting is the most efficient and cheapest method. According to the practical cutting mechanism, a cutting mechanism is designed to carry out the wire-shearing experiment. For ANSI 1022 billet which is cut by the cutter of R 0.2mm inner fillet with billet-clamping method, the shearing quality and shearing force are investigated. It is revealed experimentally that the shearing zone on the shearing surface which acted by cutter is greater. While, the shearing zone on the other side which acted by cutting die is smaller. The billet cut with close cutting die has a burr. In order to investigate the roundness and the maximum thickness of shearing zone on the shearing surface, Taguchi method is used. The control factors are wire material, inner fillet of cutter, the clearance between cutter and cutting die, and the clamping force on cutting die. It is displayed that small clamping force and ANSI 1022 wire billet result in well roundness on both sides of a billet. The maximum thickness on shearing zone is smaller when the billet is cut by the cutter without fillet (R0).

碩士
高苑科技大學
機械與自動化工程研究所
100
This research deals with three kind of commonly used hot rolling wire rods, that is, the screws, nuts and hand tools etc., which are machined after 5 dies are changed to make surface reduction rate from 0% to 45% and so on. The mechanical property influence, the metallography microstructure and the change of spheroidization quality will be observed after investigating the spheroidization treatment. The result shows that when the surface reduction rate after the wire rod is spheroidized reaches to 23.5%. This result makes the strength and hardness of cold machining formed materials decreased, however its ductility obviously increases. Right at this moment, the surface reduction rate matches the cold forging steel materials chosen as the lowest mechanical property. But at the stage the machining hardness does not obviously increase. If the life time of the mold is increased, that will improve the optimal condition when the carbon steel and the annoy steel are made. On the other hand, the steel material of the wire rods with different carbon amount is spheroidized at a higher slope along with the increase of the surface reduction rate, This shows that the carbide's spheroidization driving energy of the alloy steel wire rod is bigger. When the surface reduction rate reaches at 23.5%, the spheroidization rate may achieve 97%. However, the spheroidization rate of wire rod due to low carbon content only achieves 93% the highest , when the surface reduction rate reaches at 35%. Therefore, the wire rod's spheroidized quality will be influenced by the carbon content. Before the cold forging steel materials with lowest mechanical property are chosen, the first step is to design the final size of the wire materials and then to calculate the necessary size of the wire rod materials from the optimal surface reduction rate. Keywords: Spheroidization Treatment, Surface Reduction Rate, Spheroidization Rate, Wire Drawing

碩士
國立高雄第一科技大學
行銷與流通管理所
90
Due to the situation of the down-stream industry emigrating seriously, the circumstance of over-supply and Taiwan’s participating in WTO, the traditional manufacturing industries of wire rod steel in Taiwan are suffering from the strong competition among the large steel companies all over the world. Local wire rod industry makers should devise a way to satisfy the customer in the markets with vigorous competition and ascendance to insure the competitiveness of business on the good customer service. In addition, a customer relationship management technology may also make the company have more advantageous position. The purpose of this study is to investigate the factors with which the electronic commercial technique and production-marketing process affect the customer relationship management and the future intention. The subjects of this research focus on the wire rod down-stream users and the domestic wire rod manufacturers in Taiwan. This research uses three research methods: literature review, in-deep interviews and questionnaires to verify these hypotheses. The results of this study show that the wire rod industry manufactures considers the benefits from using CRM as follow: 1) integrating down-up stream, 2) distributing the functions of information, 3) using the Internet to decrease operation time, 4) decreasing the data error rate, 5) expending the range of markets, 6) shorting order time and conveniences, 7) improving efficiency in the internal ERP system and computerization, and 8) improving the quality and quantity of management dimension and operation dimension by the internal ERP system. According to this study, the technological dimension of electronic commerce and the management dimension of product-sell process of a company are positively related to the factors of trust, commitment and customer satisfaction in the operation dimension of customer relationship management. On the other hand, the technological dimension of electronic commerce is most outstanding. Trust, commitment, customer satisfaction is positively related with future intension. The factors in management dimension and operation dimension affect few because there was little difference on the quality, product cycle, capacity and price in each wire rod supplier. Therefore, it cannot be a key point of keeping a long-term cooperation because of the capacity is limited to the equipment of a factory and the price decided by the market. Accordingly, these are not the most important factors that affect the cooperation will of both sides. This study finds that the relation commitment of steel wire rod industries is grounded on the customer relationship management. The results of overall-satisfaction analysis also show that: 1) the commitment and satisfaction affect the future intension notably, and positively and the commitment of customers is more important than the trust of customers. It is because that the cost of a steel wire rod industry to invest in building a factory and purchasing equipments is very high; 2) the commitment and customer satisfaction affect positively the future intension, and the factors of commitment have greater influence than customer satisfaction. Consequently, the commitment of a long-term cooperation can lead to the intension of future cooperation. Again, customer satisfaction bound up with future intension is proved.

碩士
台灣首府大學
工業管理研究所
102
The complaints arising from the customer on rod processing for different products, relative to produce a wide variety of cases, which were often analyzed by senior staff according to their experience. However, in recent years because of the streamline enterprise personnel policy, and the knowledge and experience accumulated heritage, it often produce misanalysis, which easily lead to new customer complaints and cannot quickly understand the cause of the defects and the direction of improvement. Therefore, in order to enhance the efficiency of the new personnel analysis for the customer complaints case, in addition to the usual training and experience, the expert systems can also build a series of confirmed factors for a variety of defects inferred from customer complainants. This study focuses on the confirmation of the defects of wire rod inferred by complaining customers using an expert system for the X steel plant. In the study, the customer responses with inferred factors were taken as the basis of determination of the defect factors, and then which were confirmed by integrating and constructing knowledge through SQL databases, and structuring inference engine through the neural network and case-based reasoning techniques. In addition, the study provided the information analysts appropriate manner as a reference information by the combined operation of the web-based interface, with the "Defect Analysis Table", the "Defect and Process Control Collating Table" and the "Defects and Process Improvement Recommendations Table". The three Tables can be used to explore the position which is prone to defects in the production process or the processing system. Furthermore, the study suggested some preventive methods to reduce defects, and then let the company can reduce costs and improve product quality through the use of resources. Keywords：wire rod defects, expert systems, database, neural network

碩士
高苑科技大學
經營管理研究所
98
Abstract This research focuses on steel product-wire rod coil and uses the Taguchi quality engineering and regression analysis method to optimize the tensile strength of low carbon steel wire rod in stelmor cooling of rolling process, expect to find out the optimum control parameters of SAE 1012 ( low carbon steel grade ) in stelmor cooling process. According few related studies on the stelmor cooling process, the process can be improved by step by step. The Smaller-The-Best quality characteristic is the low tensile strength, the L8(27) Orthogonal Array is selected to design experiment and run the experiments. In the initial study, to avoid distrubing the manufacture processes and machines, we determine the five important control parameters, carbon percent, laying temperature, slow cooling cover, transfer roller speed, blower position, to be our experimental control factors. According to experimental results, we can determine the optimum control parameters. From the wire tensile strength experimental result, we can find out the optimum control factors are lower carbon percent and higher laying temperature. The other factors are not significant to affect the wire tensile strength. Keywords：Taguchi Method, Quality Engineering, Orthogonal Array, Quality Characteristic, Stelmor Cooling, Singal Noise Ratio

碩士
高苑科技大學
機械與自動化工程研究所
102
Abstract In this study, three kinds of rolled wire rod materials constantly used on screws and bolts are concerned. The relation among mechanical properties, phase ratios, micro-structures and grain sizes is investigated on the wire materials of low carbon steels and extra low carbon steels. Also the Electron Microscope and Energy Spectrum analysis are applied to distinguish the type of Precipitation phase. The results are shown that the precipitation phase of titanium nitrides and titanium carbides exist in the extra low carbon steel so that the hardness ratio of the wire materials with extra low carbons after cold forming is higher than that of the wire materials with low carbons for around 10%. In addition, The wire rod materials with course ferrite grains mainly added by titanium elements in extra low carbon steels could be made as the wire materials for cold processing and it still kept good ductility not necessary to be softened under heat treatment. So in the research of function comparisons, to save cost expenses through cold forming without annealing process is expected. Keywords: Extra low carbon steel, Phase ratio, Grain size, Precipitation phase.

碩士
國立中正大學
企業管理所
97
The steel industry is the foundation of all industries, it is the basic industry of the national construction and the national defense industry, and it has also being called the mother of industries. Due to the consideration of economic development and security reason of the national defence, the governments of most countries often taking high tariff, quota to limit or classifying as the specific project of importing etc., in order to protect the development of the national steel industry. The production facilities, equipments, raw materials and energy consumptions are all more costly than the general industries. Thus, the steel industries are highly capital and skill intensive. The steel industry in Taiwan has been through and strived for half a century. Nowadays, the complete foundation of the steel industry in Taiwan has been established and proceeds to grow up. However, the breakout of the global financial crisis last year causes the sudden stagnation for the demand of the steel-made products, and brings the severe crisis ever for the steel industry. In addition, the drastic fluctuation of the international petroleum price also causes the production costs to go up as well as the prices of a variety of energy and raw materials. Under the severe environment today, the profits in the steel industries have being shrinked. That forces the managers in this industry to take steps to deal with this situation. In addition to making great efforts to develop the new products, to increase the profit margins, and to maintain basic and smooth operations of produciton lines and the prerequisite in the scale of economy, managers can’t help but make more cost-effective decisions. Among these decision problems, the optimal productin planning problem and product mix problem are two of the most crucial problems to the steel industry. Thus, the objective of this research is to develop the mathematical programming models to cope with these two decision problems. By considering the hot-rolled line of wire rods and reforming bars material for real industry production, we take various kinds of limiting conditions under the realistic environment into the mathematical programming models, and obtain the best production planning and the optimal product mix for the case steel firm so that the corporate''s minimum total production costs and the best profit-making level can be achieved.