Construction Of Furnace Research Articles

Freeze–thaw durability of cement-based geothermal grouting materials

The required vertical closed loop geothermal heat exchanger size highly depends on the peak demand of the building when no complementary heat source is included. If grouting materials were able to resist freezing temperatures, a mean-demand designed geothermal heat exchanger would be sufficient to fulfill the energy requirements of the building, either preventing the oversizing of the geothermal heat exchanger or the necessity of an hybrid system and therefore saving their associated cost. This paper analyzes the freeze–thaw durability of five cement based geothermal grouting mortars. One was a neat cement (N) and the rest contained either limestone sand (L), silica sand (S), electric arc furnace slag (EAF) or Construction and demolition waste (CDW). Mortars were either exposed up to 25 freeze–thaw cycles or to continuous water curing to analyze the influence of both treatments on the volumetric water content, flexural, compressive and pipe to mortar adherence loads and on the thermal conductivity of the resulting mortars. Results show no significant damage due to the freeze–thaw cycles applied to all the mortars but the neat cement, probably due to the non-saturation of the core of the probes. Although neat cement presented no flexural resistance to freeze–thaw cycles and the probes were severely damaged, no influence was observed on the thermal conductivity of the core material, denoting that any loss of efficiency of a geothermal heat exchanger must be due to the increment of the contact thermal resistance between the pipe and grout or the creation of new contact resistances in the fractures of the grout itself.

Iron Will: Cleveland-Cliffs and the Mining of Iron Ore, 1847–2006 by Terry S. Reynolds and Virginia P. Dawson (review)

Reviewed by: Iron Will: Cleveland-Cliffs and the Mining of Iron Ore, 1847–2006 by Terry S. Reynolds and Virginia P. Dawson Clayton Ruminski Iron Will: Cleveland-Cliffs and the Mining of Iron Ore, 1847–2006. By Terry S. Reynolds and Virginia P. Dawson. (Detroit: Wayne State Univ. Press, 2011. 351 pp. Cloth $44.95, ISBN 978-0-8143-3511-6.) Terry S. Reynolds and Virginia P. Dawson’s cowritten Iron Will is an excellent example of business and industrial history, a relatively narrow field of study. Sanctioned as a company history by the last remaining independent iron-mining company now known as Cliffs Natural Resources, the book chronicles “Cleveland Cliffs’ rise to prominence in the late nineteenth century, its struggle to survive the consolidation of the steel industry . . . , the shift from a labor intensive to a capital-intensive business . . . , and the company’s recent transition to a global iron merchant” (3). Despite the authors’ stringent focus upon the company itself, they also succeed in showing the importance the mining of iron ore in the Great Lakes region had on the Midwest and the subsequent development of the iron and steel industry in the late nineteenth and early twentieth centuries. As a professor of history at Michigan Technological University, Reynolds has published several essays on the mining of iron ore in the Great Lakes region and the Cleveland Iron Mining Company, while Dawson, president of History Enterprises, Inc., based in Cleveland, has authored several institutional histories. Included within the authors’ chronological narrative of Cleveland-Cliffs are a number of themes that embrace management, fear of mineral depletion, the cyclical nature of the iron and steel industry, and labor and technology (4). Throughout the book, these themes are well examined, particularly the company’s focus on iron-mining technology and its evolution, such as its transition to greater mechanized open-pit operations and underground mining in the 1860s and 1870s, which led to the depletion of high-grade ores, and the development of taconite pellets in the 1950s. In addition to the mining of iron ore, Dawson and Reynolds also focus on the company’s product diversification throughout various economic crises. Of particular interest is the company’s decision to go into the charcoal iron-smelting business during the depression years of the 1890s by utilizing Michigan’s vast woodlands for fuel for their blast furnaces and by exploiting its by-products, such as wood alcohol and acetone. By the turn of the twentieth century, Cleveland-Cliffs used partnerships to leverage capital resources, as well as investment in other companies, in order to ensure a market for their ore, one such example of the latter being the construction of a large blast furnace in Warren, Ohio, known as the Trumbull-Cliffs Furnace Co., a joint venture between Cleveland-Cliffs and the Trumbull Steel Co. Supplementing the authors’ extensive and detailed narrative is the use of a vast amount of primary sources, including internal reports and correspondence from the company, as well as daybooks and interviews with company personnel. Their sources, which include more than one hundred illustrations, provide a detailed exploration of the company’s history and deliver a unique glimpse [End Page 139] into one of the country’s most important raw-material providers. Despite its sanctioning by Cliffs Natural Resources, the authors successfully removed many of the downfalls that often accompany such a project, including discernible bias within the text and oversight of unscrupulous company labor relations and practice; however, removing all bias is a daunting task. Those interested in mining technology, iron and steel, business, economic, regional and industrial history will find Iron Will both an informative and important addition to the field. Both Dawson and Reynolds present a well-researched economic and industrial history of a company so essential to the Midwest’s industrial prowess throughout the twentieth century, yet with the expanding global economy, Cliffs Natural Resources is currently presented with similar challenges that had plagued them throughout the nineteenth and twentieth centuries. Clayton Ruminski Youngstown State University Copyright © 2014 The Kent State University Press

Effect of an Improvised Furnance on Students Performance in Foundry Technology in Technical Colleges in Rivers State, Nigeria

The purpose of this research was to determine the effect of an improvised furnace on students’ performance in foundry technology in technical colleges in Rivers State. The study adopted research and development incorporating quasi-experimental design. It involved the use of control group, pre-test – post test design. The population of 194 students from four technical colleges in Rivers State were used for the study. The instrument for data collection was made up of Foundry Technology Achievement Test (FTAT) developed by the researcher. The achievement test consists of 50-multiple choice items with four options of A-D. The test items were identified and selected from the content of (NABTEB) syllabus on metal work technology. Test re-test method was used to establish the reliability of the instrument; the tests yielded 0.70,073 and 0.72, 0.74 for the first and second tests respectively. Four experts in metal work technology were involved in both face and content validity of the improvised furnace and 200 multiple-choice test items. The results obtained from the test scores were compiled and analyzed using statistical tools such as; percentage, mean, and analysis of covariance (ANCOVA) in answering the research question and testing the hypothesis at 0.05 level of significance. improvised furnace had positive effects on students’ performance in foundry (15.32). The difference in performance between those taught using improvised furnace and those taught using conventional teaching aids was found to be significant at 0.05 levels of significance. Based on the findings of the study, the researcher recommended that government, technical college principals and the different agencies should provide fund to procure the materials and component for designing and constructing furnace by the teacher for teaching foundry in technical colleges in Rivers State. Also, constant power supply, generators, accumulators, anvil, steel vessel, pipes and electric blower should be provided and distributed by the ministry of education to the technical colleges for construction of furnace for effective teaching of foundry in Rivers State. The industries, government, non-governmental agencies and private enterprises and communities should provide components, consumable materials necessary for teaching foundry and supply the materials directly to the individual technical colleges in Rivers State. DOI: 10.5901/mjss.2014.v5n1p649

Atom probe study of grain boundary segregation in technically pure molybdenum

Molybdenum, a metal with excellent physical, chemical and high-temperature properties, is an interesting material for applications in lighting-technology, high performance electronics, high temperature furnace construction and coating technology. However, its applicability as a structural material is limited because of the poor oxidation resistance at high temperatures and a brittle-to-ductile transition around room temperature, which is influenced by the grain size and the content of interstitial impurities at the grain boundaries. Due to the progress of the powder metallurgical production during the last decades, the amount of impurities in the current quality of molybdenum has become so small that surface sensitive techniques are not applicable anymore. Therefore, the atom probe, which allows the detection of small amounts of impurities as well as their location, seems to be a more suitable technique. However, a site-specific specimen preparation procedure for grain boundaries in refractory metals with a dual focused ion beam/scanning electron microscope is still required.The present investigation describes the development and successful application of such a site-specific preparation technique for grain boundaries in molybdenum, which is significantly improved by a combination with transmission electron microscopy. This complimentary technique helps to improve the visibility of grain boundaries during the last preparation steps and to evidence the presence of grain and subgrain boundaries without segregants in atom probe specimens. Furthermore, in industrially processed and recrystallized molybdenum sheets grain boundary segregation of oxygen, nitrogen and potassium is successfully detected close to segregated regions which are believed to be former sinter pores.

A fire test on continuous reinforced concrete slabs in a full-scale multi-story steel-framed building

To further understand the fire behavior of concrete floor slabs, this paper examines the results of a fire test on continuous concrete floor slabs in a full-scale three-story steel-framed building. The case under experimental study models the reality of fire conditions more closely than previous tests and involves the construction of a special furnace on the building's second floor to heat four panels (two by two) and steel beams on the third floor. The experimental results are investigated in detail and consider the furnace temperature, temperature distribution, vertical and horizontal deflections, and failure patterns of the structural elements during the heating and cooling phases. The testing data indicate that the number and locations of the heated panels in the floor also have a considerable effect on the continuous concrete floor's fire behavior, apart from the boundary constraint conditions provided by the adjacent structural members. In addition, the steel beams exhibit better fire-resistant performance than that observed in standard fire tests depending on their structural integrity and the interaction between structural members. In contrast to its high-strength bolt connections, the building's welded-bolted connections do not cause local buckling of the steel beams subjected to fire.

Chemical Experts at the Royal Prussian Porcelain Manufactory

The royal porcelain manufactories in eighteenth-century Continental Europe were sites of production that implemented chemistry in three different areas: manufacture of porcelain paste, preparation of pigments for ornamenting porcelain and construction of furnaces along with choice of fuel for firing porcelain. This paper provides evidence for the Royal Prussian Porcelain Manufactory in Berlin being a site of chemistry by studying the activities of its so-called Arcanisten, laboratory workers (Laboranten) and chemists between 1787 and 1795. It pays particular attention to the questions of who implemented chemistry and how this was done.

Considerações sobre a concepção do primeiro forno brasileiro para avaliação de lajes e vigas, carregadas, em situação de incêndio

Esse trabalho apresenta parâmetros que norteiam a concepção de equipamento de laboratório destinado a avaliar lajes e vigas em escala natural, com carga, e em situação de incêndio. Parâmetros de interesse, como dimensões internas, taxas de elevação da temperatura com o tempo, infraestrutura para instalação do equipamento, entre outros, são avaliados à luz de normatização nacional e internacional em vigor. Ao final, espera-se que esse relato de exercício de concepção e construção do primeiro forno horizontal brasileiro estimule a construção de futuros equipamentos desse tipo, auxiliando pesquisadores nacionais e internacionais da área a iniciar semelhante, e árdua, empreitada.

BÖHLER L329 VMR

Abstract Böhler (or Boehler) L329 VMR is a nickel base alloy with good resistance to stress-corrosion cracking. The alloy is used in the construction of industrial furnaces. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: Ni-699. Producer or source: Böhler-Uddeholm North America.

BÖHLER L312 VMR

Abstract Böhler (or Boehler) L312 VMR is a nickel base alloy with good resistance to stress-corrosion cracking. The alloy is used in the construction of industrial furnaces. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: Ni-697. Producer or source: Böhler-Uddeholm Corporation.

The Coke and Iron Ore Materials Kinetic Characteristics and Quantitative Indicators of Blast Furnace Process

The most important problem at the blast furnace process developing is the great coke consumption decreasing at the minimization of the general energy costs. One of the most effective ways of iron-making technical progress is the iron ore materials and coke physicochemical properties improvement which allows to increase the iron productivity and decrease the specific coke rate without construction of new blast furnaces and concentrating mills. Some of the quality indicators of iron ore raw materials and coke and their influence on the main parameters of a blast furnace smelting are considered in the paper.

Influence of various factors on the breakage rate of glass fibre

Technical glass fibre fabrics generally are made from alkali-free (R2O<1%) alumina borosilicate E-type continuous glass fibre yarns. These materials have high (up to 600°C) thermal resistivity, low thermal conductivity and are inert to the majority of chemical reagents, resistant to many organic and mineral acids, weak alkali, water and high-pressure steam. E-type glass fibre is used as thermal and acoustic insulating material up to 600°C.The quality of glass fibre as well as of its fabrics depends on many parameters, including quality of raw and refractory materials, furnace construction and parameters, distribution and stoichiometric proportion of chemical elements in filaments, redox ratio in the glass, etc.In order to clarify main causes of filament breakage and surface defects, the morphology and compositional profiles of glass fibre were studied using Fourier Transform Infrared spectroscopy (FTIS), Scanning Electron Microscopy (SEM), X-ray microanalysis and X-ray powder diffraction.

Heat Transfer in Fire Resistance Furnaces - Experimental Investigation of the Variation of Heat Impact due to Furnace Construction and Control Thermocouples -

Heat Transfer in Fire Resistance Furnaces - Experimental Investigation of the Variation of Heat Impact due to Furnace Construction and Control Thermocouples -

SEM and TEM Investigations of Recovery and Recrystallization in Technically Pure Molybdenum

Abstract Beside traditional applications of refractory metals, e.g. in high temperature furnace construction, lighting or glass industry, one of the most important molybdenum products nowadays are large plates which are frequently used as targets for the sputtering of molybdenum layers in thin-film transistor liquid crystal displays. For the hot rolling of the sintered pre-material, the control over the recovery and recrystallization behavior is of particular importance. Molybdenum tends to a very recovery controlled behavior during hot deformation, at which the dislocations arrange into subcell boundaries instantaneously. These pronounced recovery processes seem to consume a large amount of the stored deformation energy for the actual recrystallization. On the other hand, recovery provides the future recrystallization nuclei. For a comprehensive characterization of these microstructural processes, electron microscopy appears to be the most proper means. The aim of this study is to evaluate the significance of electron channeling contrast imaging, electron back scatter diffraction and transmission electron microscopy with regard to recovery and recrystallization processes in molybdenum. Furthermore, appropriate specimen preparation procedures for scanning and transmission electron microscopy are described.

Virtual calibration of a supply air temperature sensor in rooftop air conditioning units

Supply air temperature (SAT) measurement is an important element in sequencing control and automated fault detection and diagnosis (AFDD) in HVAC systems to ensure the comfort of building occupants, decrease energy consumption, and lower maintenance cost. But in rooftop air conditioning units (RTUs) with gas-fired heating, the accuracy and reliability of manufacturer-installed supply air temperature (MSAT) sensors are notoriously difficult to attain. Experimental evaluations in this study, covering both the cooling and heating modes and using both direct measurements of a MSAT sensor and a multi-sensor measuring grid, demonstrate that direct measurements cannot obtain the true value of SAT in RTUs in the heating mode. Erratic measurement errors exist due to nonuniform temperature distribution and intensive thermal radiation in a compact chamber. An innovative indirect virtual calibration method for an MSAT sensor is proposed in this article to solve this issue. It demonstrates that a virtual calibrated MSAT sensor can provide accurate results when combined with a linear correlation for offset error that depends on heating stage and outside air damper signals. The linear correlation could be determined using the calculated temperature difference between the predicted theoretical true value of SAT and the direct MSAT measurement. This virtual calibration method is generic for all RTUs with similar construction of gas furnaces and can be implemented for long-term use. Further experimental evaluation and uncertainty analysis prove that the virtual calibration method can accurately predict the true value of SAT in RTUs within ±1.2°F (0.7°C) uncertainty. This economical technology will not only improve energy management of packaged units in sequencing control but also better facilitate real-time automated control and fault detection and diagnosis.

Construction of Sodium Heat-Pipe Furnaces and the Isothermal Characteristics of the Furnaces

Due to an excellent temperature flattening ability, annular sodium heat pipes operating from 500 °C to 1200 °C have been widely used as liners for isothermal furnaces to provide uniform and stable temperature zones. In order to develop the capabilities to fabricate liquid-metal heat pipes, an apparatus for fabricating sodium heat pipes was set up at the National Institute of Metrology (NIM), China. In this paper, the newly developed fabrication apparatus, the detailed procedures for manufacturing sodium heat pipes, the sodium heat pipes, the constructed furnaces for realizing the aluminum freezing point, and their isothermal characteristics are described. The experimental results showed that the biggest temperature differences within 150 mm from the bottom of the thermometer well in an aluminum point cell placed in the sodium heat-pipe furnaces were better than 15 mK, when the temperatures of the furnaces were controlled at approximately 657 °C.

MECHANISMS KNOWLEDGE OF THE FLOW AND WEAR IN THE BLAST FURNACE CRUCIBLE WITH THE NODAL WEAR MODEL

The presence of thermocouples in the lining of crucibles has become a general practice in the new construction of blast furnaces. The Nodal Wear Model (NWM) has also emerged as an instrument that, while using experimental data, obtains nodal variables whose experimental measurement is not possible: global coefficient of pig-iron/refractory heat transfer [formula] and nodal temperature Ti. Starting from these nodal properties, the wear of the lining or the growth of scabs may be controlled, independently of the mechanisms responsible for them. In the same way, the properties and influence zone of the dead man in the hearth of the blast furnace may be calculated, along with those regions where the fluid is allowed to move without any other restrictions than the ones of the corresponding viscous flow (raceway hearth region).

A low-cost vacuum casting equipment for aluminium alloys

Some of the advantages inherent in the vacuum casting technique such as improved mechanical properties and elimination of shrinkage have been replicated in a low-cost design. Melting and vacuum requirements of the equipment were determined based on a furnace capacity of 15 kg of aluminium. Clay-based refractory and insulating bricks were used for furnace construction. The vacuum system was made from locally available materials and designed for efficiency required for vacuum casting. The equipment was used to melt and cast small-sized specimens using the lost-wax technique and compared with green sand and ceramic mould cast specimens. Tensile and shrinkage tests were carried out on all specimens. The results of the tensile tests were 123, 98 and 113 MPa for the vacuum cast, green sand cast and ceramic mould cast specimens, respectively. Furthermore, shrinkage defect which is common to both green sand and ceramic mould casting was eliminated in vacuum casting. The vacuum casting equipment cost an equivalent of about U.S $1000.00 (One thousand dollars) to construct and can be easily scaled-up for large-sized castings by increasing furnace capacity and the size of the moulding flask.

Increase in the operating efficiency of heating units using ceramic fibers and objects based on them

The operating efficiency of heating units using ceramic fibers and objects based upon them is demonstrated: furnace warm-up time and cooling is saved by a factor of five, there is an overall reduction in fuel consumption with the use of light-weight objects in continuously operating furnaces by 10 - 15%, and in periodically operating furnaces by 45%, and there is a reduction in capital expenditure in furnace construction by a factor of 5 - 10 (according to USA data). In addition, use of thermal insulation materials not only saves energy resources, but in many cases it speeds up production processes, improves ecology, and simplifies lining construction.

Effect of experimental parameters on erosive abrasive wear behaviour of cobalt based (stellite) plasma transferred arc hardfaced surface

Material damage caused by the attack of particles entrained in a fluid system impacting on a surface at a high speed is called ‘erosive abrasive wear’. Carbon steels are the most common ones used in the fabrication and construction of boilers and furnaces. Typical erosive abrasive wear situations encountered in boilers are caused by the impact of hard particles such as ash and clinker entrained in flue gases. These situations can lead to serious damage. Engineering components encountering erosive abrasive wear conditions during operation can be improved by hardfacing with a wear resistant material. In this paper an attempt has been made to analyse in detail the effects of different experimental parameters such as specimen temperature, standoff distance, orifice diameter, air pressure and abrasive particle size on the erosive abrasive wear behaviour of cobalt based alloy (stellite) surface produced by plasma transferred arc hardfacing process. It is found that air pressure caused a predominant effect on the wear rate of a hardfaced surface, compared to other variables. Both experimental and statistical investigations show that the wear resistance of the cobalt based alloy (stellite) surface is four times better than that of the substrate (carbon steel).

Periodic heat wave determination of thermal diffusivity of clays

The responses of Ankaful, Tetegu (# 1 & 2) and Mamfe clays to periodic heat waves were analyzed to deter-mine the thermal diffusivity values. The temperature amplitude attenuated with depth of penetration, while the phase shift increased. The thermal diffusivity values ranged from 3.0 - 9.5 x 10P-7P mP2P/s by amplitude decay and phase lag calculations based on Fourier theory of heat conduction. The large variation in the thermal diffusivity was attributed to non-homogeneity of the clay samples. The damping depths, heating and cooling rates were evaluated to identify most suitable clay samples for construction of kilns and furnaces for high temperature ind-ustrial applications. Tetegu # 1 and Mamfe clays exhibited characteristics of high thermal diffusivity, heat rete-ntion and depth of penetration, and were considered as suitable processing refractory media.