Cast Iron

A small painting by Jan Brueghel the Elder, portraying a blast furnace, is to be found at Galleria Doria-Pamphilj in Rome. The authors discuss this painting while considering the contemporary Flemish paintings of ironworks. From the peculiarity of this painting, from the scene it portrayed and from news about Jan Brueghel´s stay in Italy, the authors conclude that this painting may represent a Bergamasque blast furnace built in Latium.

The mono-azo dye, Orange II, solution was substantially degraded with cast iron particles under varied conditions of experimental variables such as pH, initial dye concentration and cast iron dosage.At all solution pH studied, the degradation efficiency achieved was > 90%. With an initial dye concentration of 100 mg/L and optimum cast iron load of 28.56 g/L, the optimum degradation efficiency of 97.63% was achieved at pH 3. With same cast iron load and solution pH, more than 95% dye degradation efficiency was achieved at different initial Orange II concentrations ranging from 50-500 mg/L. The efficiency of cast iron particles in degrading Orange II dye was compared with that of pure elemental iron used in other study. Cast iron particles showed better degradation efficiencies than elemental iron that too at relatively lower dosages. Ultimately, from the results it can be inferred that cast iron fillings can be successfully applied to treat textile effluents containing high dye concentration and treatment efficiency can be enhanced by optimizing the reaction conditions.

The complex role of sulfur in magnesium treated iron was evaluated in both ductile and compacted graphite irons. At elevated levels, sulfur can act as a harmful element resulting in magnesium-neutralization and increased dross formation but is also beneficial and essential at lower levels because it promotes suitable nuclei for graphite precipitation. It also exercises graphite nodularity shape control at intermediate augmented sulfur levels. Ductile and compacted graphite irons were prepared in an electric furnace with the same base iron melt chemistry for both the laboratory and production foundry trials. In the case of ductile irons, a late sulfur-addition during post-inoculation and after magnesium treatment produced high nodule counts, reduced occurrence of carbides, and provided excellent nodularity. These results were recorded with less than 0.01 weight percent of sulfur additions. Significant improvements in nodule count, nodularity and chill reduction were found when calcium, as a calcium silicon alloy, and iron pyrites (FeS 2 ) were employed together as a post-inoculant. Re-sulfurizing a magnesium treated iron for compacted graphite iron production, in conjunction with knowing the initial base iron sulfur enables control of the graphite nodularity. Specially formulated iron sulfide briquettes (FeS 2 ), dissolved more rapidly than granular iron pyrites yielding sulfur recoveries in the range of 85 to 90 percent. With the advantage of little to no odor they were found to be an improved and more reliable sulfur additive in both compacted graphite and ductile irons. nodularizing elements such as titanium and aluminum are used in CG production. This production research was a response to the desire of many foundries to add alternative elements to "denodulize" magnesium treated ductile iron rather than elements that might contaminate other cast components being produced. (

The main objective of this work is to investigate the mechanism of sulfur diffusion from the mold (sand resin P-toluol sulfonic acid mold, sulfur-containing acid) in liquid cast iron in order to limit the graphite degeneration in the surface layer of iron castings. A pyramid trunk with square section samples was cast. On the opposite side of the feed canal of the samples, steel sheets with different thicknesses (0.5, 1, and 3 mm) were inserted with the intention of blocking the diffusion of sulfur from the mold into the cast sample during solidification. The structure evaluation (graphite and matrix) in the surface layer and the casting body was recorded. The experimental results revealed that by blocking the direct diffusion of sulfur at the mold-casting interface, a decrease of the demodified layer thickness (for 0.5 mm steel sheet thickness) is obtained until its disappearance (for steel sheet thicknesses of more than 1 mm). The paper contains data that may be useful in elucidati...

The present paper reviews original data obtained by the authors from recent separate publications with additional unpublished data, specifically concerning the Lanthanum (La)’s role in the solidification pattern and graphite formation in gray cast irons. Iron melting at 0.018–0.056%S, a 3.7–4.1% carbon equivalent (CE) and less than 0.005%Alresidual are inoculated with La-bearing FeSi alloys at different associations with other inoculating elements. Complex Al-La small inclusions as possible better nucleation sites for (Mn,X)S compounds and La-Ca presence in the body of these sulfides, which possibly provide better nucleation sites for flake graphite, are identified in 0.026%S cast iron. At a lower sulfur content (0.018%S), La,Ca,Al-FeSi alloy still has a high efficiency, but more complex La-bearing alloys are recommended for a higher dendritic austenite amount (LaBaZrTi–FeSi) or for lower eutectic recalescence (LaBaZr–FeSi). La has limited but specific benefits at 0.05–0.06%S irons,...

The chemical composition of cast iron used for casting ball bearing machining disks was varied to optimize the properties such as castability, hardenability, and durability in ball machining. The cast iron characteristics were most strongly dependent on the Ni content and the carbon saturation degree, S c . This paper describes the types of test specimens, the working conditions, and the experimental results. The increase of the degree of carbon saturation reduces the tendency to form shrinkholes in the castings. The decrease in the Ni content negatively affects the final hardening treatment. A way to control solidification defects in cast iron, by reducing the Ni content, has been verified on cast disks.

The objective of this paper is to review the factors influencing the formation of degenerated graphite layers on the surfaces of ductile iron castings for chemical resins-acid molding and core-making systems and how to reduce this defect. In the resin mold technique the sulphur in the P-toluol sulphonic acid (PTSA), usually used as the hardener, has been identified as one factor causing graphite degeneration at the metalmold interface. Less than 0.15% S in the mold (or even less than 0.07% S) can reduce the surface layer depth. Oxygen may also have an effect, especially for sulphur containing systems with turbulent flows in the mold, water-bearing no-bake binder systems, Mg-Silica reactions, or dross formation conditions. Despite the lower level of nitrogen in the iron melt after magnesium treatment (less than 90 ppm), nitrogen bearing resins have a profound effect on the frequency and severity of surface pinholes, but a limited influence on surface graphite degeneration.

during all the process of execution of the finished products. The control of casting defects is a major problem for most small foundries where a variety of problems can occur. It's very important to have an opposite process assessment, to perform preventive activities, and to make use of research techniques for better loss prevention. The first step is to properly identify the casting defect and then to classify the defect according to a casting defect classification system. Casting production involves various processes which include pattern making, molding, core making, melting pouring, shell breaking, shot blasting etc. It is almost impossible to produce defect free castings. Occurrence of the defect may involve single or multiple causes. These causes can be minimized through systematic procedure. This paper deals with casting defects in Diverter Wheel. A Diverter wheel is a part used in lift on which metal cable is wound to give up and down movement to the lift.

during all the process of execution of the finished products. The control of casting defects is a major problem for most small foundries where a variety of problems can occur. It's very important to have an opposite process assessment, to perform preventive activities, and to make use of research techniques for better loss prevention. The first step is to properly identify the casting defect and then to classify the defect according to a casting defect classification system. Casting production involves various processes which include pattern making, molding, core making, melting pouring, shell breaking, shot blasting etc. It is almost impossible to produce defect free castings. Occurrence of the defect may involve single or multiple causes. These causes can be minimized through systematic procedure. This paper deals with casting defects in Diverter Wheel. A Diverter wheel is a part used in lift on which metal cable is wound to give up and down movement to the lift.

In this study, tensile and abrasive wear performances of two different quality as-cast ductile irons have been examined at various temperatures between 25 and 600°C. Tensile tests were carried out with a strain rate of 3ϫ10 Ϫ4 /s. Wear tests were performed under a compression stress of 5.7 N/mm 2 , by rubbing samples on 125 mm Al 2 O 3 abrasive grains. In the temperature range of 100-300°C, where serrated flow is observed during tensile testing, tensile strength values of both ductile irons were invariable. Above 400°C, further increase of temperature caused dramatic decrease in tensile strength. As a general trend, abrasive wear resistances of the both ductile irons increased with increasing tensile strength. Exceptionally, maximum resistance to abrasive wear is obtained from both ductile irons at 100°C, probably due to dynamic strain aging. KEY WORDS: abrasive wear; ductile iron; high temperature; strain aging; tensile characteristics.

The surface hardening process is one of the high temperature treatment precess wich is applied only on the surface of the object of the treatment so that it result an object with superficial hardness without changing the interior matrix shape of the object. The materials used in this reseach are perlitics gray cast iron and low carbon steel wich are easily available an yhe market to increase the hardness and resistance of the surface of the object througt borodisation. As the diffusion material, boron, wich was derived from ferro boron powder was used. The experiment was conducted by veryng temperature of 800 o C and 875 o C, wich the resisting periods of 1 hour, 3 hours, 5 hours. From this experiment, it was expected that there was an increase in hardness and reistance of the object surface without changing its interior matrix shape. After conducting the experiment and some test namely metallography test, hardness test, and resistence test, it showed that there was diffusion proces...

High-Chromium White Cast Iron is a material highly used in mining and drilling shafts for oil extraction, due to its high wear resistance. However, because of the austenitic matrix found in the as-cast state, an adequate heat treatment cycle is necessary. This paper studies the effects of different cooling media after a destabilization treatment on the microstructure, hardening and abrasion resistance behaviors of a hypoeutectic high chromium white cast iron. The results show that although air cooling followed by immersion in CO 2 can effectively reduce the retained austenite, this is not enough to transform completely the retained austenite into martensite. The low retained austenite percentages improve bulk hardness, but they decrease the abrasion resistance of the high chromium cast iron. The best combination of hardness and wear resistance was found in the samples cooled in air, due to the percentage of retained austenite and a moderate precipitation of chromium carbide.

Step plate castings with section thicknesses of 1.5 mm to 6 mm and individual (single) castings with section thicknesses of 2 mm to 6 mm were produced using a ductile iron chemistry. Microstructures of these thin wall ductile iron castings were characterized quantitatively using an image analyzer. Matrix structure and (amount of pearlite, ferrite, and massive carbides), graphite structure (volume fraction, nodule size, nodule count, and nodularity) were investigated as a function of section thickness. Pearlite content, nodule count, and nodularity increased with decreasing section thickness, whereas the nodule size decreased. Nodule count exceeded 2000 nodules per mm 2 at the thinnest sections. Statistical analysis was performed to investigate the effect of casting parameters on the microstructure.

This paper is focused on evaluating the influence of iron content on SDAS factor, Al5FeSi phase size, and porosity of secondary aluminum alloy AlSi7Mg0.6 used in the automotive industry. These characteristics were evaluated by quantitative analysis on sand-casted experimental alloys with various iron contents (0.128; 0.202; 0.429; 0.75; 1.264 %). Results have shown a decrease of SDAS factor with increasing of iron content. Al5FeSi phase average length and thickness values increased with the rising iron content. These dependencies began to reveal themselves when the iron content reached values around the critical value of the iron content -Fecrit. (0.475 % Fe). The average area of pores (2.05 -3.8 %) and pore size (39 597 -70 332 µm 2 ) increased with increasing of iron content (0.128; 0.75; 1.264 %) too.

This paper is focused on evaluating the influence of iron content on SDAS factor, Al5FeSi phase size, and porosity of secondary aluminum alloy AlSi7Mg0.6 used in the automotive industry. These characteristics were evaluated by quantitative analysis on sand-casted experimental alloys with various iron contents (0.128; 0.202; 0.429; 0.75; 1.264 %). Results have shown a decrease of SDAS factor with increasing of iron content. Al5FeSi phase average length and thickness values increased with the rising iron content. These dependencies began to reveal themselves when the iron content reached values around the critical value of the iron content -Fecrit. (0.475 % Fe). The average area of pores (2.05 -3.8 %) and pore size (39 597 -70 332 µm 2 ) increased with increasing of iron content (0.128; 0.75; 1.264 %) too.

Sn-based Babbitt coatings are widely used for sliding in hydrodynamic bearings. The Babbitting of bearing surfaces is among others accomplished by casting; however, this implies some disadvantages such as segregations, or susceptibility to shrinkage defects. Thermal spraying represents a promising method to overcome these challenges. To date, no studies on Babbitt coatings deposited by means of low-pressure cold spraying (LPCS) are available in the literature. In this study, a first attempt is made to produce a Sn-Sb-Cu-based composite coating reinforced with alumina particles by means of LPCS which enables the coating of internal diameters (IDs) of cylindrical components. A tailor-made feedstock was utilized which consists of a powder mixture of Sn, Sb, Cu and alumina. The composite coating is investigated with regard to its microstructural and tribological characteristics using scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), as well as dry sliding experiments. Metallographic investigations demonstrate the feasibility of depositing an alumina-reinforced Sn-Sb-Cu-based composite coating with a dense microstructure and low porosity. The composite coating mainly consists of Sn, SbSn, Cu and hexagonal CuSn. Despite a small fraction of alumina particles, the microhardness of the composite coating is primarily determined by the formation of SbSn intermetallic phases dispersed in the soft Sn-Sb-rich matrix. The composite coating possesses a coefficient of friction of 0.43 ± 0.01 and wear coefficient k of 17.27 ± 7.77 9 10 -5 mm 3 N m -1 sliding against a 100Cr6 counterbody.

U ovom je radu predstavljeno numeričko modeliranje mehaničkog ponašanja nanokompozitnih materijala, zasnovano na računalnoj homogenizaciji kao višerazinskoj metodi modeliranja. Kao uvod, dana je kratka povijest nanomaterijala i teorijska pozadina o ugljičnim nanocijevima i numeričkom modeliranju istih. Također, dana je teorija o kompozitnim materijalima, budući se na teoriji kompozita zasniva i teorija nanokompozitnih materijala. Posebna pozornost obraćena je međudjelovanju između osnovne matrice nanokompozitnog materijala i ugljične nanocijevi kao poboljšanja te je predstavljen način numeričkog modeliranja takvih međudjelovanja koji se najvećim djelom zasnivaju na slabim van der Waals vezama. U svrhu analize tih međudjelovanja razvijen je i poseban program, koji na osnovu zadanih parametara omogućuje modeliranje veze između matrice nanokompozita i nanocijevi ili između dva različita sloja unutar višestrukih ugljičnih nanocijevi. Problem modeliranja nanokompozitnih struktura je višerazinski problem, stoga je dio rada posvećen višerazinskim metodama, gdje je veća pažnja posvećena računalnoj homogenizaciji prvog reda. Upravo je na računalnoj homogenizaciji prvog reda i upotrebi reprezentativnog volumnog elementa baziran program za numeričko modeliranje nanokompozita. U svrhu verifikacije programa, dana su 4 modela nanokompozitnih materijala, različitih karakteristika, a dobiveni rezultati uspoređeni su s rezultatima drugih autora.

The effects of magnesium variation and austempering heat treatment on mechanical and microstructural properties of ductile iron produced using the rotary furnace were investigated. Varied quantity of magnesium-ferrosilicon in the range of 0.03 % to 0.06 % were used as nodulirizer to treat 4 kg mass of molten metal per ladle by sandwich process and poured into sand mould.  Mechanical test (tensile, hardness, fatigue, impact and wear) and micro-structural examinations were carried out on the four samples produced. Samples C and D of 0.056% and 0.061% magnesium showed an improvement in their micro-structural properties due to the presence of more graphite nodules. Hence, they were observed to have exhibited better tensile strength of 598.07MPa and 609.03MPa. The fatigue strength also increased to 501.91MPa and 509.27MPa respectively. These two samples were further subjected to austempering heat treatment by heating to 850ºC for austenitization and soaked for homogenization for one hour...

The market for ductile cast iron as a substitute material increases every year. The material structural performance is strongly dependent on the microstructure. Micromechanics can help in understanding the role played by the microstructure constituents as well as the effects associated to the shape of the spheroids, their density, surface roughness, etc. The potential of application for micromechanics modeling can be further increased if features such damage mechanics and residual stresses are incorporated. In this paper, a micromechanics modeling approach based on the unit cell development has been developed paying particular attention to the role and the behavior of the constituents. Residual stresses, resulting from the cooling down to room temperature, have been demonstrated to be critical for an accurate prediction of the non-linear behavior of the DCI in the early deformation range. As far as damage mechanics is concerned, it has been demonstrated that voids nucleating from debonded spheroids are not sufficient to explain catastrophic failure at the macroscale while the occurrence of additional ductile damage in the matrix material is the driving process for rupture in ferritic DCI.

This is to certify that the thesis entitled "Development of Cu-Based Metal Matrix Composites Using Silicon Carbide, E-Glass Fiber and Multiwalled Carbon Nanotubes as Reinforcement" being submitted by Mr. Harshpreet Singh to the National Institute of Technology Rourkela, for the award of the degree of Masters of Technology (Research) is a record of bonafide research work carried out under my supervision and guidance. The results presented in this thesis have not been submitted elsewhere for the award of any other degree or diploma. This work in my opinion has reached the standard of fulfilling the requirements for the award of the degree of Masters of Technology (Research) in accordance with the regulations of institute.

Spent fuel canisters stored in halite (NaCl) deposits (salt beds) are subject to a severely corrosive environment when the hot brine inclusions, rich in calcium and magnesium chlorides, migrate to the canister. Since no data base exists on corrosion in halite brines, a survey was made of the corrosion resistance of potential canister materials in other concentrated brine environments. Corrosion-resistant metals include Ta r Ti Code 12, TiPd Alloy, Inconel 625, Hastelloy C-276, and Fe-base 29-4 Alloy. Although carbon steels have cost and availability advantages, they suffer from excessive corrosion rates in brines. Corrosion-resistant nonmetals include carbon. Teflon-type fluorocarbons, epoxide coatings, and polymer cements. While these materials are not suitable for constructing the canister, they could be used as a protective coating on a carbon steel canister. On the basis of this survey, we recommend a coated carbon steel canister, used with cathodic protection. It is important to start a test program to gather a data base on the corrosion of materials in halite brines and to verify the suitability of canister materials. vii SUMMARY Corrosion is a major consideration in the selection of materials for canisters to store spent fuel in geologic media. These canisters are required to isolate the spent fuel from the environment, and they must be retrievable during the first 25 to 50 years of storage. A canister must be able to survive in the storage medium, retaining sufficient structural integrity to prevent radioactive release during both storage and retrieval. If the retrieval option is not exercised, permanent disposal is accomplished by sealing the burial site. The type of geologic storage medium currently favored for spent fuel storage is halite (NaCl) deposits. The major disadvantage of halite as a storage medium results from the presence of liquid brine. These brine inclusions can migrate up the thermal gradient to a storage canister and there produce an extremely corrosive environment that severely limits the selection of canister materials. Brines in halite deposits contain not only NaCl, but also high concentrations of the more soluble calciun and magnesium chlorides. These chlorides hydrolyze readily and create acidic brines that are much more corrosive than the more neutral NaCl brines. Canister corrosion rates are also accelerated by the elevated temperature resulting from self-heating of the spent fuel and by dissolved oxygen. Corrosion of the inside of the canister is not expected to be a problem, although if moisture or organic materials are introduced along with the spent fuel rods, hydrolysis or radiolysis could result in high pressures and perhaps hydrogen attack. No data base exists on the corrosion resistance of materials An halite brines, and indeed, these brines have not yet been well characterized. Other IX

The Iron Ages in the West and China did not start with the first appearance of iron but with the first functional applications of iron. Although the initial trajectory leading to these applications was similar in both regions, the West entered its Iron Age with bloomery iron, while China replaced bloomery iron with cast iron. Our zoomed-out approach suggests that this divergence had very little to do with differences in technological capital between the two regions, but was influenced mainly by the applications demanded of iron within the respective socio-political environments. We propose that access to the technologies associated with bronze and pottery, to mass produce cast iron, differentiated China from the West and set each region on its respective course. We further propose that the West's trajectory to adopt bloomery iron was fixed through its reliance on specialists (blacksmiths) who could work independently of these technologies. China's trajectory to adopt cast iron was fixed by the socio-economic powerbase required to set up a cast iron industry at a state level, which was reinforced by an Imperial monopoly from the Han dynasty. Essentially, we have investigated why the West did not develop cast iron technology earlier than China, and why China developed cast iron technology 2000 years before the West.

The control of parameters such as liquid fraction, holding time, and cooling rate during thixoforming can help control the final microstructure of the thixoformed part, thus improving its mechanical properties. This study intended to investigate conditions required to obtain martensite in hypoeutectic gray cast iron at 3.1% CE (carbon equivalent) deformed in the semisolid state. Samples heated up to 1130, 1135, and 1145 ∘ C (liquid fractions of 10, 30, and 45%) were compressed into platens without any holding time (0 s). If a sample presented a martensitic structure for 0 s holding time, new samples were retested at the same temperature for 30, 60, and 90 s holding times. The die casting process was simulated by allowing the platens to become locked after hot compression. Samples that cooled in the locked platens were submitted to higher cooling rates than samples that cooled with the platens open and presented martensite instead of the conventional ferrite and pearlite. Thus, the factor that had the greatest influence on the formation of martensite was the cooling rate rather than stress. The thixoforming process presented good morphological stability, which is highly desirable for industrial applications.

We are also grateful to Stephanie Chang for providing us with background information on the Portland Bureau of Water Works network and sharing with us results of her analysis study of network vulnerability, direct economic impacts of earthquake disruptions, and maintenance and mitigation costs. Helpful comments on an earlier draft were provided by Ann Fisher.

The aim of this study was to investigate the effect of the austempering treatment applied on ductile graphite cast iron with different chemical composition; microstructure, hardness, tensile strength and wear resistance. For this purpose sand mold casting models of camshafts were prepared and casting simulation was carried out with the NOVACAST program. The casting quality of camshafts and production process was optimized. For nodulizing process, Fe-Si-Mg alloy has been used and Fe-Si-Ba-Ca-Al alloy has been used for inoculation process. The casting has been done 1430 • C and the pouring time in 15 s. In different analyzes, a cast camshaft subjected to a 90 min austenitizing process at 900 • C under a mill vacuum furnace. The austenitized cam shafts have been quenched into the molten salt bath (50% KNO3 + 50% NaNO3) at 260 • C temperature, held for 30, 60, 90, 120, 150, 180 and 210 min and then cooled in air. Microstructures analysis of cam shafts have been examined by optical microscope and scanning electron microscopy (SEM), mechanical tests (hardness, tensile tests and wear tests) have been performed. Results show that austempering heat treatment increases the tensile strength of cam shaft as-cast condition. In this study, the tensile strength values of the austempered structure, camshaft core which has been formed in 120 minute duration which has the combination of excellent strength and ductility, have been brought from the level of 711.08 MPa to 1424.28 MPa.

The aim of this study is to investigate the effects of heat austempering and induction hardening on the wear properties of GGG60 ductile cast iron for camshaft production. For this purpose, camshafts have been produced by sand mould casting method. Fe-Si-Mg alloy has been used for inoculation process to achieve iron nodulization. The casting has been done between 1410-1420 • C. The casted camshafts have been austenitized at two different temperatures (800 and 900 • C) and time intervals (60 and 90 min) under controlled furnace atmosphere. The austenitized camshafts have been quenched into the molten salt bath at 360 • C, held there for 90 min and then cooled in air. This way, austempering heat treatment has been applied. After that, surface hardening process was conducted using induction hardening machine with medium frequency. Microstructure of camshafts has been examined by optical methods and mechanical tests have been performed. Results show that austempering heat treatment increases the wear resistance of camshaft, compared to as-cast condition. Wear resistance of the camshaft increases with increasing austenitizing temperature, time and with induction hardening. The lowest weight loss of 0.62 mg has been obtained for the induction hardened camshaft austenitized at 900 • C for 90 min.

Iron is a very important element required for haemopoietic activity hence the need to assess iron profile of some apparently healthy university students. Twenty-five (25) male and twenty-five (25) female students of Madonna University, Elele, were used for this study. The subjects gave their consent and 5ml of venous blood sample was collected. The samples were analyzed using standard methods. Parameters analyzed include Total serum Iron (TSI), Unsaturated Iron Binding Capacity (UIBC), Total Iron Binding Capacity (TIBC), Haemoglobin concentration (Hb) and Packed Cell Volume (PCV). The result obtained showed that the males had a significantly (p<0.05) higher values of 43.77±3.5% and15.20±1.1g/dl than females with 39.83±3.1% and 13.52±1.1g/dl for PCV and Hb respectively. Result for the Total Serum Iron gave a value of 17.26±2.4 µmol/l for males and 13.40±2.7 µmol/l for females. Conversely, UIBC and TIBC were significantly (p<0.05) lower in males with 45.95±5.2 and 63.21±4.4 µmol...

The treatment of inoculation of white cast iron with carbide precipitations that consist of increasing the number of primary austenite grains is not as well-known as the treatment of inoculation of gray cast iron in which the number of eutectic grains increases. In the studies included in the publication, experiments were carried out using the addition of ferrotitanium as an inoculant for chromium cast iron. The Cellular Automaton Finite Elements (CAFE) module of ProCAST software was used in order to analyze the formation of the primary structure of hypoeutectic chromium cast iron in a casting of various thicknesses. The modeling results were verified using Electron Back-Scattered Diffraction (EBSD) imaging. The obtained results confirmed obtaining a variable number of primary austenite grains in the cross-section of the tested casting, which significantly affects the strength properties of the obtained chrome cast iron casting.

This method is based on the determination of similarity criterion Z as the average temperature difference between the reference and analyzed curves in the solidification region. The purpose of this work is to describe the thermal express-analysis (TDA) device created by us and the substantiation of the reliability and sensitivity of the results of the new method, including the definition of a two-sided confidence interval using Student's t-test. The error of the method was determined with the Student's criterion taken into account. The high sensitivity of the method to the metallurgical prehistory of the gray and white cast iron melts was confirmed. The method has been successfully tested under laboratory and experimental-industrial conditions on induction melting cast iron. The new method uses a disposable environmentally friendly submersible steel sampler with a heat-resistant coating inside and out. The method allows for the quick adaptation to the conditions of specific foundries (especially with the frequent changes of classes and types of cast iron) due to replenishing the database of the reference samples. The basic features of the new method are its universality, self-adaptability, speed, relative simplicity, and high sensitivity to the metallurgical prehistory of molten iron.

Volume changes of the binary Fe-C alloy with nodular graphite were forecast by means of the Cellular Automaton Finite Differences (CA-FD) model of solidification. Simulations were performed in 2D space for differing carbon content. Dependences of phase density on temperature were considered in the computations; additionally density of the liquid phase and austenite were deemed as a function of carbon concentration. Changes of the specific volume were forecast on the base of the phase volume fractions and changes of phase density. Density of modeled material was calculated as weighted average of densities of each phase.

The study presents a mathematical model of the crystallisation of nodular graphite cast iron. The proposed model is based on micro- and macromodels, in which heat flow is analysed at the macro level, while micro level is used for modelling of the diffusion of elements. The use of elementary diffusion field in the shape of an averaged Voronoi polyhedron [AVP] was proposed. To determine the geometry of the averaged Voronoi polyhedron, Kolmogorov statistical theory of crystallisation was applied. The principles of a differential mathematical formulation of this problem were discussed. Application of AVP geometry allows taking into account the reduced volume fraction of the peripheral areas of equiaxial grains by random contacts between adjacent grains. As a result of the simulation, the cooling curves were plotted, and the movement of "graphite-austenite" and "austenite-liquid” phase boundaries was examined. Data on the microsegregation of carbon in the cross-section of ...

Formation of the shrinkage defects in ductile iron castings is far more complicated phenomenon than in other casting alloys. In the presented paper changes the ductile iron density during solidification is analyzed. During the solidification path the influence of the temperature, phase fractions and phase composition is taking into account. Computer model, using cellular automata method, for estimation of changes in density of ductile iron during its solidification is applied. Results of the solidification modeling for Fe-C binary alloys with different composition in the castings with a different wall thickness are presented. As a result of calculations it was stated that after undercooling ductile iron below liquidus temperature volumetric changes proceed in three stages: pre-eutectic shrinkage (minimal in eutectic cast iron), eutectic expansion and the last shrinkage.

From the present study, niobium additions of 1.79% and 3.98% were added to a 15% Cr-3% C white iron, and their effects on the microstructure, hardness and abrasive wear were analyzed. The experimental irons were melted in an open induction furnace and cast into sand molds to obtain bars of 45 mm diameter. The alloys were characterized by optical and electron microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900 • C for 30 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under three loads (58, 75 and 93 N). The results show that niobium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming niobium carbides at the beginning of the solidification process; thus decreasing the eutectic M 7 C 3 carbide volume fraction (CVF) from 30% for the base iron to 24% for the iron with 3.98% Nb. However, the overall carbide content was constant at 30%; bulk hardness changed from 48 to 55 hardness Rockwell C (HRC) and the wear resistance was found to have an interesting behavior. At the lowest load, wear resistance for the base iron was 50% lower than that for the 3.98% Nb iron, which is attributed to the presence of hard NbC. However, at the highest load, the wear behavior was quite similar for all the irons, and it was attributed to a severe carbide cracking phenomenon, particularly in the as-cast alloys. After the destabilization heat treatment, the wear resistance was higher for the 3.98% Nb iron at any load; however, at the highest load, not much difference in wear resistance was observed. Such a behavior is discussed in terms of the carbide volume fraction (CVF), the amount of niobium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.

Tribological problems and corrosion degradation have been recognized as essential risks for total joint replacements, especially for all-metal arthroplasty. Few studies have focused on the interactions between tribology and corrosion (tribocorrosion) for implant materials. This paper addresses the importance of understanding tribocorrosion and the evaluation of such materials in simulated biological environments. Due to the complex effect of proteins on tribocorrosion, which has been demonstrated in previous studies, this study focuses towards understanding the effects of amino acids as aspects of material degradation. Dulbecco's Modified Eagle's Medium (DMEM) is a cell culture solution. It contains comparable amount and types of amino acids to normal synovial fluid in human joints. 0.36% NaCl solution was employed to isolate the biological species. Three materials were tested; High carbon (HC) CoCrMo (contains 0.19% carbon), low carbon (LC) CoCrMo (widely used materials for total joint replacement) and stainless steel UNS S31603 (316L). Integrated electrochemical tests supported by measurement of friction and near surface chemical analysis were carried out to enable their tribocorrosion behaviour to be fully characterized. As a general conclusion, amino acids were found to react with materials under tribological contacts and form complex organometallic/oxides which lubricate the metallic sample surface. Tribocorrosion plays a very important role in material degradation in the studied environments. HC CoCrMo shows superior wear, corrosion and tribocorrosion resistance -the material characteristics and their effect on the different tribocorrosion processes are discussed.

Iron and steel materials have been extensively used in various engineering fields thanks to their promising merits of abundant resources, low cost, easy workability, stable quality and promising comprehensive mechanical properties. However, friction which occurs on the surface can result in wear and then weaken the service performance of iron and steel materials, deleterious effects of damage/failure, lowering in work efficiency and noise pollution happen finally on normal operations. Inspired by non-smooth surfaces in nature, surface textures are able to realize a positive influence on tribological performance of materials and achieve effective anti-friction/wear-resistant, drag reduction and noise reduction during practical service. This review began with a brief introduction of surface texture. The research progress of the surface texturing for improving tribological performance of iron and steel materials in China was reviewed and summarized in the sight of specific applications.

Considering the rising prices of materials, the enterprises engaged in processing of alloys and in the manufacture of castings seek for ways of production cost reduction. One way of saving is consists in utilisation of recycled materials or in re-melting of foundry returns. This study is focused on evaluation of mechanical and thermo-mechanical properties of the Al-Cu alloy (RR.350) at multiple re-melting in cast condition. The research team focused on a change of following properties: tensile strength, hardness, microhardness, change of chemical composition of the alloy, change of the microstructure of the alloy and dilatation after re-melting.

Influence of repeated using of alloys on base Al – Cu is the goal of this study. Alloy RR350 was used for this study. Specimens for tension examination were casted to the metal forms, which were protected by preservative coating. Pouring temperature and temperature of iron mold were controlled in order to keep constant conditions of experiments for all testing samples. From poured samples the testing rods were prepared to determination of tensile strength under laboratory (20 °C) and under higher temperature (with maximum about 350 °C). Specimens were also taken for determination of hardness (HBS) and metallographic analysis from poured samples. Metaloographic analysis was evaluated by using microscope GX 51, which equips polarization light with magnification from 12.5 to 1000. Thermo-mechanical properties were carried out at the author ́s working place – Department of Foundry Engineering, Faculty of Metallurgy and Material Engineriing, Technical University of Ostrava. Description o...

RS Analysis and DF Analysis have been applied to backscattered ultrasonic signals obtained from three different cast iron samples in order to investigate the fractal nature of the microstructure of these materials. The results show a scenario with two distinct regions whose calculated parameters can be used to estimate their fractal dimensions.

This study presents an analysis of the abrasive effects of sediments from the bed of the Acre River, Brazil, on the wear of three different ferrous materials employed in the manufacture of impellers of centrifuge pumps used to catch raw water. In order to evaluate the abrasive wear and specific wear coefficient (k) as a function of sediment concentration, tests were conducted in samples of SAE 8620 steel, nodular cast iron and gray cast iron by using a rotary-ball abrasion meter. These tests employed abrasive slurry with concentration of 1, 2, 3, 5 and 10 g L-1 of sediments in distilled water. The volume of worn material as a function of the relative velocity of water flow in relation to the impeller blades was mathematically estimated. The experimental results showed that: i) The semi-angular and semi-rounded shapes of the sediments from the Acre River produced evidence of micro-grooving and plastic deformation in the three metallic alloys; ii) SAE 8620 steel showed higher resistan...

Drinking water distribution networks form essential components of all urban centres. Water mains buried in the soil-backfill are exposed to different deleterious reactions, with the result being that the design factor of safety may significantly degrade, leading to structural failure. In particular, metallic distribution and trunk mains are subject to corrosion. Proactive pipeline management, which entails timely maintenance, repair, and renovation, can increase the service life of pipes. Several nondestructive evaluation techniques have recently become available to measure the remaining wall thickness of metallic pipes. In this paper, a previously developed analytical model based on Winklertype pipe-soil interaction (WPSI) is cast in a "possibilistic" framework to translate the remaining pipe wall thickness to current structural factor of safety. The WPSI model takes into consideration external (traffic, frost, etc.) and internal (operating and surge pressures) loads, temperature changes, and loss of bedding support and the reduction of pipe structural capacity in the presence of corrosion pits. Uncertainties associated with the input data-parameters are handled using fuzzy arithmetic operations and interpreted through possibility theory. A Monte Carlo type random sampling method is carried out for performing sensitivity analyses to identify the critical data-parameters that merit further investigation.

This paper proposes a method using probabilistic risk analysis for application to corrosion associated failures in grey cast iron water mains. External corrosion reduces the capacity of the pipeline to resist stresses. When external stresses exceed the residual ultimate strength, pipe breakage becomes imminent, and the overall reliability of a water distribution network is reduced. Modelling stresses and external corrosion acting on a pipe involves uncertainties inherent in the mechanistic/statistical models and their input parameters. Monte Carlo (MC) simulations were used to perform the probabilistic analysis. The reduction in the factor of safety (FOS) of water mains over time was computed, with a failure defined as a situation in which FOS becomes smaller than 1. The MC simulations yielded an empirical probability density function of time to failure, to which a lognormal distribution was fitted leading to the derivation of a failure hazard function. A sensitivity analysis revealed that the contribution of corrosion parameters to the variability of time to failure was more significant than the combined contributions of all other parameters. Areas where more research is needed are identified.

Several factors may contribute to the structural failure of cast and ductile iron water mains, the most important of which is considered to be corrosion. The ANSI/AWWA C105/A21.5-99 10-point scoring (10-P) method is commonly used to predict corrosivity potential of a given soil sample using certain soil properties. The 10-P and other scoring methods use binary logic to classify the soil either as corrosive or noncorrosive. Fuzzy logic extends binary logic in this context as it recognizes the real world phenomena using a certain degree of membership between 0 and 1. This paper presents a fuzzy logic expert system capable of predicting the deterioration of cast and ductile iron water mains based on surrounding soil properties. The proposed model consists of two modules: a knowledge base and an inference mechanism. The knowledge base provides information for better decision-making and is developed in a two-tier fuzzy modeling process. First in direct approach, the expert knowledge generates a subjective model to describe the characteristics of the system using fuzzy linguistic variables. Later in system identification, the field data is used to develop an objective model, which is eventually used in conjunction with the subjective model to provide a more reliable knowledge base for the expert system. The inference mechanism uses fuzzy approximate reasoning methods to process the encoded information of the knowledge base.