bluuebunny/crossref_metadata_2025 huggingface dataset:
Advances in the Development of Carbidic ADI
Authors: Sebastián Laino , Sikora Jorge Antonio , Dommarco Ricardo C.
Published: December 2010

Carbidic ADI (CADI) is a new type of Austempered Ductile Iron containing free carbides in the microstructure, providing a particular combination of wear resistance and impact toughness. In this work, four CADI variants were evaluated, in which carbides were promoted by alloying with chromium. Tests performed under the low stress abrasion condition imposed by the ASTM G65 standard show that CADI can increase the wear resistance up to 100 % when compared with conventional ADI austempered at the same temperature. The carbide content must be higher than 10 % to promote a considerable reinforcing effect. However, at this carbide content level, the impact toughness varies between 7 and 11 J/cm2 for unnotched samples. These values are much lower than those of conventional ADI, but higher than those of other abrasion resistant materials, like white irons. Some CADI variants were also evaluated in field tests, producing abrasion under either low stress or high stress conditions. For this purpose, two CADI prototype parts were studied: screw segments for animal food extruders (low stress abrasion) and wheel loader bucket edges (high stress abrasion). The results gathered showed that CADI behaves satisfactorily under low stress abrasion, but the performance is not so good under high stress conditions. To analyze the differences in the abrasion response, scratch tests were performed in order to evaluate the interaction between the abrasive tip and the microstructure.
The Effect of Partial Melting Homogenization on the Mechanical Properties of Thick Section Austempered Ductile Iron Containing 2% Mn
Authors: Sheikholeslam A. , Nili-Ahmadabadi Mahmoud , Rassizadehghani J.
Published: December 2010

Elements such as Mn and Mo may be added to ductile iron to improve its hardenability and mechanical properties, but segregation of these elements could result in the reduction of mechanical properties and must therefore be considered during the manufacturing of thick section ductile iron. In this research the microstructures of cast specimens containing 2% Mn were studied by optical microscopy and scanning electron microscopy. Results showed that manganese segregates in the intercellular areas while silicon segregates in the regions around graphite nodules. Partial Melting Homogenization (PMH) was carried out on the samples to reduce segregation. Analysis of the results showed that homogenization has been done successfully and segregation in the ductile iron matrix was significantly reduced. The successful effect of homogenization was also studied on austempered samples. PMH prior to austempering resulted in a very uniform bainitic microstructure. Tensile tests were carried out on the samples which showed improved mechanical properties due to combined PMH process and austempering process.
Microstructure and Properties of Isothermally Quenched High Boron White Cast Iron
Authors: Zhang Jian Jun , Gao Yi Min , Xing Jian Dong , Ma Sheng Qiang , Yan Wan Qin , Yan Jing Bo
Published: December 2010

Microstructure and properties of isothermally quenched high boron white cast iron were investigated in this paper. The results show that the microstructure of high boron white cast iron is mainly composed of many continuous and netlike eutectic borides, pearlite and ferrite under as-cast condition. The microhardness of Fe2B ranges in 1200-1600HV whose value seems to approximate that of (Fe,Cr)7C3–type carbide (HV1200~1800) in high chromium white cast iron. After isothermal quenching, the matrix transforms into lower bainite in which carbide precipitations are arranged in parallel rows at an angle of 60 deg to the long axis of the plates, but the morphology of boride remains nearly unchanged compared with its as-cast condition. Moreover, precipitation particles with the size of about 1~4 μm can be found in the matrix of isothermally quenched high boron white cast iron. Impact fracture morphology of isothermally quenched high boron white cast iron indicates that fracture propagated more easily through boride/matrix interface than through matrix.
Effect of Rare Earth-Al Additions on the Structural Variations of Medium Carbon Fe-B Cast Alloy
Authors: Yi Da Wei , Xing Jian Dong , Fu Han Guang , Ma Sheng Qiang , Liu Zhu Xin
Published: December 2010

This study investigates the effect of rare earth and aluminium composite modification on the structural variations of as-cast and heat treated medium carbon Fe–B cast alloys. The as-cast microstructure of Fe–B cast alloy consists of the eutectic boride, pearlite, martensite and ferrite. Moreover, compared to a netlike distribution of the coarse eutectic borides in the unmodified alloy, the eutectic boride structures in the modified alloy are greatly refined and less interconnected. After heat treatment, the phases in Fe–B cast alloy consist of the boride and martensite. The addition of rare earth helps to increase the number of the rod-shaped and round borides in Fe-B cast alloy during austenitizing. Compared to the unmodified alloy, the boride volume fraction and Rockwell hardness of the modified alloy have no significant change, however, the average area of each boride in the modified alloy is lower and the impact toughness is higher.
Abrasion Behavior of High Cr-V-Nb Cast Iron
Authors: Hirose Masanori , Yamamoto Kaoru , Miyahara Hirofumi , Sakata Kazunori , Ogi Keisaku
Published: December 2010

A series of abrasion tests on high Cr-V-Nb cast irons revealed that the addition of MC type carbide formers, V and Nb, remarkably enhances the abrasion resistance of high Cr cast iron, and the abrasion resistance becomes higher with the increase in MC type carbides[1]. Therefore, hyper eutectic Fe-4.7%C-15%Cr-7%V-5%Nb-5%Mo alloy melt was poured into 30kg and 1kg sand mold castings to distribute different sizes of primary and eutectic carbides in hardenable matrix. The abrasion test specimens cut from each casting were austenitized at 1323K for 1h then cooled in air. These specimens were tempered at 773K for 1h followed by air cooling. The hardness of specimens was 1015-1018HV50. The rubber wheel abrasion test, a typical 3 body type one, was performed on these quenched and tempered specimens with 56-107, 107-150 and 297 μm dia. silica grit. The testing load was 86.3N and 172.5N, and the rubber wheel rotation speed was varied from 1s-1 to 4s-1. Though the higher testing load increases the wear loss, the wear rate expressed by the wear volume/( testing load × wear distance) changes depending on the wear condition and the microstructure. In case of 30kg cast specimen, the silica grit preferentially attack and scrape off the matrix, and the wear rate increases with the increase in the testing load. The fine carbides in 1kg cast specimens effectively protect the matrix from the attack of silica grit, and the wear rate decreases with increasing load which causes silica grit blunt and fracture. However, fine carbides tend to be fractured by silica grit and diminish the protective effect. Based on the worn surface structures, the abrasion mechanism is discussed comparing those of steel and eutectic 25%Cr cast iron.
Study of Feeding Parameters for the Production of Sound High-Alloyed Ductile Iron Castings with Aluminum
Authors: Belov Vladimir D. , Ten Edis B. , Drokin Alexander S.
Published: December 2010

This work deals with the problem of casting production from high-aluminum cast iron Al22D. This cast iron is characterized by unique combination of properties [1-3]: high heat-resistance in corrosive gases medium especially containing sulfurous gases; relatively low density in comparison with gray iron and satisfactory mechanical properties. In addition, castings made from high aluminum cast iron Al22D are required in many areas of mechanical engineering. However, obtaining high-quality products from this cast iron is a particular problem due to its low-casting properties, especially its high tendency to gas saturation, oxidization and forming scabs, shrinkage and gas-shrinkage defects.
Therefore, the aim of this work is the study of the castings feeding parameters. In addition, the technology of "exhaust manifold" casting of internal combustion engine designed to work in forced mode was developed on the basis of the obtained results.
Fatigue Characteristic of Spheroidal Vanadium Carbides Cast Iron
Authors: Tanaka Masahito , Shimizu Kazumichi , Ito Daijiro , Noguchi Toru
Published: December 2010

The purpose of this study is to investigate the fatigue characteristic and fatigue fracture mechanism of the high V-Cr-Ni spheroidal carbide cast iron (SCI-VCrNi) with spheroidal vanadium carbide (VC) dispersed within austenitic stainless matrix microstructure. The SCI-VCrNi that has high hardness was developed by 10mass%V adding to 18-8 stainless steel with spheroidal VC is distributed in the matrix. Firstly from the plane bending, the fatigue limit σw has been found to the 358MPa of SCI-VCrNi. Secondly, fracture surface observations were performed to clarify the fatigue mechanism of SCI-VCrNi. The fracture surface of SCI-VCrNi was so rough that the beach mark could not be observed. So, SEM was employed to observe, the fatigue fracture surface which showed a particular fatigue pattern. Also, many fracture cracks of VC were observed. In addition, the secondary cracks are shown at the interface between VC and the matrix. It can be suggested that the bondability between VC and the matrix is strong, and therefore, the propagation of cracks was delayed by the breakage of VC.
Computer Simulation of Lost Foam Process of Cast Iron
Authors: Ohnaka Itsuo , Sugiyama Akira , Konishi Kunihiko , Obana Yoshinori , Zhu Jin Dong , Sako Nobuo
Published: December 2010

Although several computer simulation codes have been developed to predict and prevent defects of lost foam castings, most of them are focused on aluminum alloy castings. This paper presents a new simulation method suitable for not only aluminum alloy but also cast iron. First of all, main assumptions and numerical schemes are as below: 1) Gas flow in the mold follows the D’Arcy’s law. 2) The gas pressure in the kinetic zone (gas gap) is uniform in each gas group and is solved by using the flow field of melt one time-step before. 3) The gas obeys the ideal gas law. 4) Latent heats of evaporative pattern degradation are simplified by an overall latent heat in which both melting and evaporation are considered. 5) The pattern absorbs heat of melt through conduction, radiation and convection. Further, X-ray direct observations of mold filling behaviors of cast iron were carried out in order to better understand the physical fundamentals and to evaluate simulated results. It was found that: 1) Mold filling behaviors of cast iron are quite different from those of aluminum alloy castings depending on the gating system and thickness of the casting. 2) Bubble floating-up often occurred in the case of the downward flow. 3) Although the newly developed simulation code could predict the mold filling to some extent, further work needs to be done, including better understanding of the heat transfer mechanism between the melt and pattern.
An Overview on Cast Iron Research at CMRDI
Authors: Nofal Adel
Published: December 2010

This report is an overview on the cast iron research carried out at the Foundry Department of the Central Metallurgical R&D Institute (CMRDI) over the past three decades. CMRDI is an national industrial research institute, whose main objective is to serve the metallurgical industries in Egypt. This overview shows selected examples of the cast iron research programs covering fundamental research, optimizing melting techniques, developing cast iron alloys for special applications, investigating novel processing techniques of cast iron rather than sand casting, e.g. continuous casting, hot and cold rolling of ductile and austempered ductile irons as well as ausforming of ADI. The influence of elastic vibrations of mechanical and ultrasonic frequencies on the inoculation and structure formation of ductile as well as white high-Cr irons has been the subject of intensive research.
The review illustrates that over 30 years, the foundry group at CMRDI has been striving to keep some sort of balance between fundamental and applied research, with the results of the latter being oriented towards developing the local foundry industry.
Study on Data Base of Modeling Concerning Casting Phenomena in Cast-Iron-Mould Simulation Systems
Authors: Ignaszak Zenon
Published: December 2010

In the foundry processes the hard modeling based on physical-mathematical formula is burdened with simplifications resulting from both: knowledge level on description of particular phenomena and level of theirs complexity. Trends observed in modeling of foundry processes and expectations of users compared with creators’ up-grades propositions are discussed. The author presents real possibilities of efficient modeling validation considering that limits of multiphysics/multiscale modeling exist for massive cast-iron castings, including the zones infected by degenerated structure (e.g. chunky graphite, dross inclusions). The model validation demands experimental-simulation studies. In the paper also the stress grid castings made of lamellar cast-iron are presented as an example of experimental model validation including the thermomechanical properties of cast-iron and furan mould and applying special Hot Distortion (HDplus®) tests of this sand. The validation of thermo-mechanical model was carried out with the use of Comsol system and chosen foundry simulation code.
Researches about the Determination of the Thermal Conductivity Coefficient for Silica Sand Moulds Used in Romanian Foundries
Authors: Ciobanu Ioan , Chisamera Mihai , Munteanu Sorin Ion , Crişan Aurel , Riposan Iulian , Bedő Tibor , Lupinca Cinca Ionel
Published: December 2010

The paper presents the results of the researches regarding the determination of the thermal conductivity coefficient of the moulds used for cast iron parts in Romanian foundries. The instantaneous values of the thermal conductivity coefficient of the moulds are influenced by the type of materials that compose the moulding batch (sand, binder, additional materials) their content (percentage) their characteristics (grains form and dimensions), but also by the temperature. Many software used for casting solidification uses a mean substitutive value. This one include the effect of heat transmission by conduction in the mould wall and the secondary processes that influence the heat transfer throw the mould wall ( burning processes of organic substances, water evaporation and re-condensation processes, mass transport processes). The determination of this mean value in the case of casting grey cast iron parts with thickness of 20 mm is presented in the paper. A regressive method was applied. The solidification time experimentally determined throw thermal analyses is compared with the solidification time obtained by simulation, in three points of the casting. The value of the substitutive coefficient of thermal conductivity that assure the best closeness between the simulated solidification time and the solidification time experimentally determined throw thermal analysis in the three points was established.
Simulation of the Ductile Iron Solidification Using a Cellular Automaton
Authors: Burbelko Andriy A. , Fraś Edward , Gurgul Daniel , Kapturkiewicz Wojciech , Sikora Jorge Antonio
Published: December 2010

The mathematical model of the globular eutectic solidification in 2D was designed. Pro¬posed model is based on the Cellular Automaton Finite Differences (CA-FD) calculation method. Model has been used for studies of the primary and of globular eutectic grains growth during the ductile iron (DI) solidification. A hyper-eutectic composition has been analyzed but this model can be used in the solidification modeling of hypo- and eutectic DI. The proposed model makes possible to trace the unrestricted growth of primary grains of two phases from the liq¬uid, transition from free to cooperative solidification, and cooperative growth of globular eutectic.
Development of Ductile Iron Material, Simulation and Production Technology to Locally Strengthen Castings
Authors: Menk Werner , Tunzini Sabine , Rieck Torsten , Honsel Christoph , Weiss Konrad
Published: December 2010

A lot of innovations in molding and casting technology and also simulation techniques have made ductile iron more and more competitive and it even competes meanwhile against steel forgings. A successful substitution of steel forgings for example is the wheel carrier for a high volume car with the Georg Fischer new ductile iron material 'SiboDur', a ductile iron family with high strength and high elongation at the same time. But there is still a great potential for ductile iron castings to substitute steel forgings, in particular in the automotive industry. One example is the crankshaft for the engine: Quite a lot of gasoline engines are equipped with ductile iron crankshafts, but for instance most of the diesel engines are still running with forged steel cranks. The reason is mostly the belief of design engineers that it is not possible to get similar fatigue limit with castings com-pared to forged steel. This belief may often be correct, but using local strengthening technologies, such as roller burnishing of bearing fillets or inductive hardening of highly stressed areas can raise the fatigue limit of casted crankshafts dramatically. The paper presents studies which show that using the right ductile iron material and optimized roller burnishing conditions can raise the fatigue limit of cast crankshafts to values even higher than forged steel ones (material 38MnVS6). But even quenched and tempered forged steel crankshafts are in the focus to be substituted by castings. It is well known that ductile iron also can be induction hardened, but the induction hardening of ductile iron is still an empirical technology. This leads to the second part of the paper: In a cooperation of Georg Fischer and RWP a research project was carried out to develop a simulation technology to predict the residual stresses in a cast crankshaft due to induction hardening under different condi-tions. The results are very encouraging and enable us today to predetermine the induction hardening conditions to get optimized fatigue behavior of ductile iron crankshafts. Of course, the findings can also be used for other applications than crankshafts.
Prediction of Microstructure and Porosity Formation of Practical Spheroidal Graphite Iron Castings
Authors: Zhao Hai Dong , Liu Bai Cheng
Published: December 2010

The mathematical model for microstructure formation and porosity prediction during solidification process of SG iron casting was established and applied to a practical brake housing casting. Quantitative microstructure analysis of specimens machined from the castings was compared with the simulation, and the two results are in acceptable agreement on nodule counts and size, pearlite fractions and hardness. It is indicated that the model can calculate the fraction of ferrite and pearlite more accurately, and specially can reflect the effect of both under-cooling during solidification and the nodules formed in eutectic period on the pearlite content. The present porosity prediction was compared with those of a former method and commercial software, which leads to that the current methods used for porosity prediction should be investigated and improved further.
Plate Fracture of Nodular Cast Iron
Authors: Heckmann C.J. , Stets W. , Wolf G.
Published: December 2010

Plate fracture is a defective fracture structure in nodular cast iron that can be found especially in the transition area of feeder, feeder neck and the cast part itself. It occurs rather spontaneously due to the fact that the exact reason for it is still unknown. The microstructure of the casting in the area of plate fracture comprises aligned graphite nodules in combination with a pronounced dendritic microstructure as characteristical features. A series of casting trials was performed in which plate like samples were produced. It could be shown by means of metallographic investigation of these samples in combination with the simulation of the solidification that specific local conditions during the solidification are the metallurgical reasons for the appearance of plate fracture. These specific conditions were the local temperature gradient and the velocity of the liquid/solid interface.
Influence of Melting Conditions on Graphite Morphology in Spheroidal Graphite Cast Iron Using Ni-C Alloys
Authors: Kato Yuji , Zou Ying , Nakae Hideo
Published: December 2010

The effects of the cooling rate, atmosphere and holding time on the graphite morphology of spheroidal graphite cast iron were studied using Ni-C alloys. Two groups of parent alloys were prepared using high purity materials, i.e., Group 1 containing the spheroidizing element of Ce, Mg or Ca, while in Group 2, S was added as an anti-spheroidizing element.
For discussing the influence of the cooling rate on the graphite morphology, 0.5g of the Group 1 samples were melted and held for 15 minutes at 1673K in an Ar atmosphere, then cooled at 1000K/min or 20K/min. The results showed that perfect spheroidal graphite could not be confirmed, while irregular graphite appeared.
The atmosphere was changed to Ar+3%H2 for preventing the oxidation, and the holding time was reduced to 10 minutes to prevent fading of the spheroidizing element. These results showed that the formation of spheroidal graphite was confirmed at the cooling rate of 1000K/min in both groups. Nevertheless, at the cooling rate of 20K/min, graphite morphology was only chunky or flake in both groups.
In order to investigate which parameter is more important for the formation of spheroidal graphite, the atmosphere and the holding time were independently changed at the cooling rate of 1000K/min. It was found that the addition of the 3%H2 did not significantly affect the spheroidal graphite formation. Moreover, the holding times of 1min and 20min also did not significantly affect the spheroidal graphite area fraction in the Ni-C alloy, while they affected the ones containing the spheroidizing elements like Mg.
Mechanical Properties and Thermal Expansion Characteristics of Low Thermal Expansion Ductile Cast Iron with same Nickel Equivalent (NiE)
Authors: Hatate Minoru , Nobuki Tohru , Kiguchi Shoji , Shimizu Kazumichi
Published: December 2010

Low thermal expansion ductile cast iron is expected to become a new structural material with high dimensional stability against temperature change. We tried to develop a new low thermal expansion ductile cast iron by means of adding C and Si to Superinver alloy. In this study we prepared four kinds of ductile cast irons whose Co contents vary from 0% to 12 %, and investigated about the effects of Co content and solution-treatments on several main characteristics such as coefficient of thermal expansion and mechanical properties. The results obtained are as follows: With increase of Co content the amount of martensite increases but this martensite can be inverse-transformed to austenite totally or greatly by solution-treatment followed with water-quenching. In the case of Co content less than some 9 % the ability of relatively larger plastic deformation can be expected in inverse-transformed austenite.
Effect of Copper Addition on Mechanical Properties of Nodular Indefinite Chilled Iron (NICI)
Authors: Prasetyo Y. , Lee S.K. , Baek Eung Ryul
Published: December 2010

Nodular infinite chilled iron (NICI) material with high content of nickel (~4.00%) was usually used as work roll in hot strip rolling mill. Microstructure of NICI was consists with nodular graphite and cementite with matrix phase consist of pearlite, martensite and ausferrite that depend on the alloying content. The introduction of copper was successfully increasing the hardenability of NICI by only using low nickel content (~2.50 %) with small addition of copper (0.52%). The development of NICI was done by hot shakeout of CO2 sand mold of as-cast iron and then isothermal heating in muffle furnace in temperature 300 oC in 6 hours to achieve ausferritic transformation. By achieving the martensite and ausferrite phase in as-cast condition, the sample will not need austenitizing and quenching process and the sample that will be free of quenching crack and thermal stress that usually occurred austenitizing and quenching process. It was confirmed by optical microscope and scanning electron microscope (SEM) observations that with the small addition of copper (0.52%), the amount of pearlite was very small (~1.00%), but with further addition of copper (2.02%), the amount of martensite was significantly increase the hardness until 51.56 HRC but the tensile strength was significantly dropped into 442 Mpa from previously 571 Mpa without copper addition. From hardness and tensile strength data it can be seen that the optimum content of copper is 1.45 % that have good combination of hardness (47.75 HRC) and moderate tensile strength (508 Mpa).
Notch Effects on Impact and Bending Characteristics of Spheroidal Graphite and Compacted Vermicular Graphite Cast Irons with Various Matrices
Authors: Nobuki Tohru , Hatate Minoru , Shiota Toshio
Published: December 2010

The object of this study is to find out and evaluate systematically how the basic factors such as graphite-shape, external notch and matrix-characteristic affect the impact and bending characteristics of cast irons. The Spheroidal Graphite (SG) and Compacted Vermicular graphite (CV) cast iron samples were prepared, and their matrixes were modified into ferritic, pearlitic and bainitic in order to make the various kinds of samples whose graphite-shape and matrix vary widely. From each sample we produced five kinds of Charpy-type specimens by adding five kinds of notches whose stress concentration factor (α) varied from 1.0 (un-notched) to 4.8. The Charpy impact value decreases greatly in the range of α from 1 to 2.3 but decreases slightly in the range of α larger than 2.3. No influence to the fracture energy in the range of α larger than 2.3. Increasing of α results in moderate elevation of transition temperature of Charpy impact value and the transition temperature of CV cast ion is lower than that of SG one. The impact value in brittle fracture region of the cast iron samples were recognized to be a little bit larger than that of cast steel sample, and it was considered to be caused by graphite which act as a kind of buffer effect against crack growth in brittle fracture.
Bending Strength of Cast Materials Reinforced with Hard Particles
Authors: Aso Setsuo , Ike Hiroyuki , Ohguchi Ken-Ichi , Komastu Yoshinari , Konishi Nobuo
Published: December 2010

Particle reinforcement via the insertion of hard particles is a promising process in materials reinforcing. Particle-reinforced spheroidal graphite martensitic cast iron (SGMC), in which mixed particles of cermet and cemented carbide are dispersed, was achieved by an insertion process. A four-point bending strength test was applied to evaluate the particle composite material. An evaporative pattern process was used on the bending-test specimen to form a composite layer in the central part. Using a combination of three sizes of cermet particles and two sizes of cemented-carbide particles, the bending strength was found to increase with each small-particle combination. The Weibull coefficient m of the four-point bending strength of the particle-reinforced composite material (PRCM) ranged from 4 to 13, and m was large in the specimen with large bending strength.
Surface Turbulence at Flow of Gray Cast Iron
Authors: Diószegi Attila , Björklind Tobias , Diószegi Zoltán
Published: December 2010

Gray cast iron has been investigated with respect to surface turbulence during mould filling. Different levels of flow velocities have been provoked in a vertically parted sand mould. The thermal resistant transparent front side of the mould permitted the observation of the flow pattern due to high speed camera registration. The registered frames including the liquid surface were investigated using image analyses. The results show good correlation between the average flow velocity and the liquid iron surface extension. Consequently it has been demonstrated that an increased absorption of hydrogen and nitrogen during mould filling is dependent on the level of liquid surface turbulence.
Selection of Cast Iron Grade for Stub-Anode Fixation in Aluminum Electrolytic Cells
Authors: Nofal Adel , Waly Mohamed , Ahmed Ahmed , Agour Mohamed
Published: December 2010

This work is a trial to reach the optimum composition and structure of cast iron used for anode fixation in the aluminum electrolytic cells. Grey iron with low- and high-phosphorus contents, spheroidal graphite irons with compositions typical of ferritic and pearlitic grades as well as grey iron with different carbon equivalent values were compared. A bench-scale experimental set up was used to simulate the operating conditions at the steel stub/cast iron collar/carbon anode connection. The change in microstructure and electrical resistance was measured at temperatures up to 850°C for 30 days, which correspond to the electrolytic cell operating conditions. The thermal expansion properties of irons were measured using a high precision automatic dilatometer. The electrical resistance at the connection was found to decrease with spheroidal graphite irons. In flake graphite irons the resistance decreases with lower phosphorus content as well as higher CE values due to the enhanced graphitization potential during solidification, which increases the contact pressure at the connection. Decomposition of ledeburitic carbides in the structure plays – to lower extent – some role in increasing the contact pressure. This contact pressure rather than the resistivity of the cast iron seems to play the dominant role in determining the electrical resistance of the connection.
Optimum Pressure Control of Molten Metals for Casting Production Using a Novel Greensand Mold Press Casting Method
Authors: Terashima Kazuhiko , Tasaki Ryosuke , Noda Yoshiyuki , Hashimoto Kunihiro , Iwasaki Junichi , Atsumi Takeo
Published: December 2010

This paper presents a novel method of sand mold press casting. In this process, molten metal is poured into a drag mold, and then the cope mold is placed on top of the drag mold, and the two molds are matched. The mold design for casting, the pouring control and the velocity control of the press have been previously clarified as key factors in the manufacture of sound products. This paper presents methods for modeling and control of the molten metal’s pressure for novel sand press casting technique. Substituting detailed information for the complex mold shape, the poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the sequential control algorithm based on the construction of an inverse system comprised of a sequential switching from higher to lower speed. The effectiveness of adaptive press casting is demonstrated by using CFD model simulations.
Technology and Effectiveness of Cast Iron Treatment by Gas Injection
Authors: Ten Edis B.
Published: December 2010

In this work the development of the technology and equipment for gas injection treatment of cast iron by inert gas (nitrogen) is presented. The equipment includes the plunging lance as a lined steel pipe with nozzles. The nozzles are thin channels, which are lined by ceramic tubes with small-diameter. The lance has a multiple use, as it has calibrated channel sizes, and provide the stability regime of gas injection treatment.
The characteristic of the gas injection technology consists of blowing of melt by gas, which is injected into the liquid cast iron through thin jet with a speed near to the velocity of sound. In this case, the dispersion of gas jets in small-sized bubbles is reached, therefore the refining effectiveness increases. The gas injection treatment shows the promotion of casting properties, improvement of homogeneity and fineness of structure, stabilization or increasing of mechanical properties, decreasing of casting defectiveness. The positive effects of the gas injection treatment is the result of complex action of the injecting gas into the cast iron melt. Together with refining and homogenizing action at specified conditions, it offers the modifying and alloying effects also.
Fundamentally New Effective Process of Casting of Hollow Cylindrical Billets of Cast Iron by the Method of Directional Solidification
Authors: Ignatievich Marukovich Yauheni , Fiodaravich Beuza Uladzimir
Published: December 2010

Advantages of new method of manufacture of hollow billets of cast iron are presented. Thermal condition of crystallizer at iterative temperature influences on its internal surface, solidification of casting and structure formation of cast iron in the conditions of intensive unilateral heat sink are examined. Comparative data on properties and operational characteristics of the components obtained by various methods of casting are shown.
Mg7-FeSi Alloy Dissolution Kinetics in the In-Mould Process
Authors: Bublikov Valentin B. , Bachinskyi Yuriy D. , Berchuk Dmitriy N. , Yasinskyi Alexander A. , Nesteruk Elena P.
Published: December 2010

This work presents the results obtained from a research on the kinetics of liquid metal front deep- advancement into granular Mg7-FeSi alloy. The phase-to-phase surface interaction, size of particles, control and speed of heat and mass exchange processes are presented in this paper. On the basis of these results it is shown that the phase-to-phase interaction can be superficial, layer, volumetric or combined.
On the Theories of Graphite Formation in Iron
Authors: Naydek Vladimir L. , Gavrilyuk Vladimir P. , Neizhko Ivan G.
Published: December 2010

The paper reviews the theories of graphite formation in iron. The hypothesis of nodular graphite formation in pure iron-carbon alloy is proposed and discussed.
Magnetodynamic Mixer-Batcher for Overheating and Pouring of Cast Iron
Authors: Dubodelov Viktor I. , Pogorsky Viktor K. , Goryuk Maksym S.
Published: December 2010

Magnetodynamic mixer-batcher is intended for adjustable inductive heating and controlled electromagnetic pouring of cast iron into crystallizers and moulds on automated casting lines, chill-mould casting machines, rotor casting machines. Also, mixer-batcher allows realizing the out-of-furnace treatment of liquid alloys. In comparison with conventional ladle pouring of grey cast iron, application of magnetodynamic mixer-batcher allows to reach more isotropic structure and properties on casting body, to increase 5-10% the mechanical properties of castings, and to refine both the metal matrix structure and dimensions of graphite inclusions. Moreover, using of magneto-dynamic mixers-batchers provides automation of pouring, economy of materials and energy re-sources, increasing productivity, and improvement of ecology.
Improvement of the Metallurgical Quality of Ductile Iron by Conditioning
Authors: Ochoa de Zabalegui Edurne , Arriaran Julian , Bicandi Juan Carlos , Ferrer Daniel
Published: December 2010

Using thermal analysis a preliminary study of the evolution of the metallurgical quality was carried out, concluding that it was strongly deteriorated during the Mg treatment, worsened at the pouring furnace. In order to improve the metallurgical quality a new phase of conditioning before the Mg treatment has been implemented. Also a special ladle was designed and built to be able to perform this new process stage in a robust manner. In this way the main objective was reached, increasing the metallurgical quality of the melt inside the treatment ladle and also at the pouring furnace, obtaining at the same time better process stability. The metallurgical quality improvement reflects at the cooling curves (stable solidification patterns), at the microstructure (higher nodule count, better graphite distribution and more ferrite content in the matrix) and at the mechanical properties (less tensile strength, higher elongation, less hardness and higher impact toughness) of the casting parts.
Microstructure Investigation of Small-Section Nodular Iron Castings with Chunky Graphite
Authors: Asenjo Iker , Lacaze Jacques , Larrañaga Peio , Méndez Susana , Sertucha Jon , Suárez Ramón
Published: December 2010

Parameters that affect chunky graphite formation in heavy-section castings have been studied in previous works which showed that inoculation and cerium addition both increase the tendency for this degenerate graphite. This suggested that laboratory study on chunky graphite formation could be performed on small castings by over-treating the melt. Though the role of silicon was not ascertained, it appeared of potential interest to also investigate its effect in relation with the carbon equivalent of the iron and the nucleation potential of the melt. Keel-blocks were thus cast using Ce or Ce-Mg treated melts, with increased silicon content (up to 4.0 wt.%) and inoculation rate as compared to usual practice. It was observed that chunky graphite systematically appeared in more or less extended areas centred on the upper part of the keel-blocks. The as-cast microstructure (graphite shape and distribution) has then been studied in relation to melt composition and additions (Ce treatment and inoculation) in both affected and non-affected areas. Finally, microanalysis of oxides and other minor phases showed them to be similar to those appearing in heavy-section castings. It may then be concluded that chunky graphite appears in light-section castings in the same way than in heavy-section castings when using over-treated melts.
Effect of Yttrium-Containing Nodulizer on the Microstructure Formation and Mechanical Properties of Heavy Section Ductile Iron Castings
Authors: Ren Qin Xin , You Ming , Yao Yun Bang , Wen Guang Min , Cai Qi Zhou
Published: December 2010

Ductile iron specimens with dimensions of 400mm×400mm ×450mm were prepared by treating the melt with an yttrium-containing nodulizer. The effect of yttrium on microstructure and mechanical properties was investigated, and the formation of degenerate graphite was discussed as well. The results show that the yttrium-containing nodulizer has good nodulization fading resistance for heavy section ductile iron, since the high melting point hexagonal oxide Y2O3 particles were formed from the nodulizer in the melt and those could act as heterogeneous nuclei for graphite nodule for a long time. Segregation of Ti and MgO at grain boundaries broke the austenite shell, resulting in graphite degeneration. When heavy section ductile iron castings with pearlite matrix were cast, graphite nodule size became finer and the nodularity of graphite nodules improved due to the addition of 0.01wt% Sb to the melt, and pearlite content in specimens increased due to alloying with Cu, Cr, Mo. The heavy section ductile iron tool bed was fabricated by treating the melt with the yttrium-containing nodulizer and Ni. The nodularity of the attached block was 85%~90%, tensile strength, elongation and impact toughness were 440MPa, 23.3% and 5.0J/cm2 respectively.
Microstructure and Properties of Cast Iron with Semi-Solid Process Using Cooling Plate Technique
Authors: Takita Mitsuharu
Published: December 2010

Semi-solid metal processing with the cooling plate technique is one of the key technologies for producing advanced materials. The multitude of cast iron families with their wide range of mechanical properties, and relatively low costs combined with the advantage of semi-solid processing allow production of high quality cast components from cast iron. The effect of semi-solid processing using the cooling plate technique on the microstructure and the properties of cast iron is studied. The investigated material is hypo-eutectic, hyper-eutectic gray iron, compacted graphite and ductile cast iron. The results indicated that the microstructure (primary austenite and graphite) becomes finer and more globular by increasing the fraction of solid. The tensile strength of semi-solid processed cast iron is relatively high compared with ordinary cast iron. The values of both the tensile strength and the elongation depend on the fraction of solid. The total fracture strength is observed to depend on the graphite morphology as well as the matrix contribution that mainly depends on fraction of solid. The wear resistance and damping capacity of cast iron were investigated as a function of the relative amount of primary fraction of solid.
Influence of Iron Powder Addition on the Structure Characteristics of Hypereutectic Grey Cast Iron
Authors: Chisamera Mihai , Riposan Iulian , Stan Stelian , Militaru Cristina , Barstow Michael
Published: December 2010

Slightly hypereutectic grey irons (< 4.5%CE), solidified in resin and metal moulds, after an addition of iron powder, either alone or with Ca,Ba,Al-FeSi inoculation (double treatment) were characterized by structure. Iron powder had a role in limiting the carbide presence, while the supplementary inoculation led to the fewest carbides in metal mould samples. No carbides were in resin mould solidification, while graphite morphology progressed from (C + B) in the base iron up to the type (B + A) in double treated iron. Polygonal (Mn,X)S compounds acting as graphite nuclei, whose characteristics depended on the applied treatment, were found: larger size/low compactness [base iron], irregular polygonal with tendency to the highest size and complex morphology [iron powder treatment] and compact polygonal/smallest size [double treatment]. Iron powder has a negative influence on the graphite nuclei and eutectic cell characteristics, but favours austenite dendrite formation, as a reinforcement for eutectic cells. It has a limited graphitizing effect, witnessed only at high cooling rates. A double addition [iron powder + inoculant] appears to be an efficient treatment, with beneficial effects on both the austenite and graphite nucleation, affecting the final structure and chill tendency.
Study on the Grooved Finger and its Application in Micro Gripper
Authors: Zheng Xiao Hu , Liu Yuan Wei , Gu F. , Kim J.K. , Lee Dong Weon
Published: December 2010

A micro grooved finger has smaller bending stiffness and can be used to improve the
performance of some micro cantilever devices. The deflection and bending stiffness of a micro
grooved finger are discussed in this paper. An analytical model of the deflection is built up to study
the effect of the groove sizes on the bending stiffness and the deflection of the grooved finger. The
calculation of the analytical model is consistent with the simulation and experiment results. When the
grooves depth is 0.5 μm, the spring constant of grooved micro finger is 19.8% smaller than that of flat
finger without groove patterns. The spring constant of the finger decreases with the increasing of the
width and depth of the groove. A novel micro electric-thermal gripper is introduced based on the
grooved finger. It consists of four sub-cantilever beams arranged at the diagonal lines of the square
frame in the end of the main cantilever structure suspended from the silicon substrate, which
guarantees an effective contact by the four-point contact area on the top surface to grab object of
importance. The thermal expansion induced deflection makes the fingers moving vertically from an
‘open’ position to a working one. The grooved fingers help to decrease the bending stiffness of the
finger and increase the deflection and the initial gap. The simple fabrication process has a feasibility
of compatible and mass production.
Finite Element Analysis of Thermo-Elastic-Plastic Creep of Super-Heat and High-Pressure Steam Pipe
Authors: Guo Xiu Li , Lu Huai Min , Xu Wen Xuan
Published: December 2010

Based on considering the material properties changed with the temperature, the finite
element analysis and the calculation method of the thermo-elastic-plastic creep damage of the
super-heat and high-pressure steam pipe in the boiler are researched. The incremental original
equation and the finite element calculation formulas are deduced. Furthermore, the stress-strain of the
pipe is calculated and the accelerating life-span test of bursting pipe is carried out. The calculation
result shows that the life-span of 12Cr1MoVG superheater pipe may be more than two hundred
thousand hours in the normal working condition, which is as over twice as length given in the Chinese
national standards. This conclusion may be referred by the engineering design department.
Application of Monto-Carlo Method in HR Investment Risk Evaluation
Authors: Lu Jing Jing , Ning Xuan Xi
Published: December 2010

Monto-Carlo method is widely used for project risk analysis. Evaluating the risk in HR
(Human Resources) investment project, which is of hi-investment and hi-return, by Monto-carlo
method is a new attempt. In this paper, by taking cost, profit and risk in the HR investment as index,
emulation model of HR investment and index function of risk evaluation were established.
Simulation about the whole investment course was done by computer program using Monto-Carlo
method. Case study of HR investment risk evaluation was done later using concrete data.
Research on Sound Absorption Properties of Aramid Micro-Perforated Composite Sound Absorbing Material
Authors: Wen Yi Fang , Rui Yan Nian , Wang Hong Wei , Chen Xin
Published: December 2010

Aramid fiber is one of the most promising materials used in secondary structure of the airplane, which has many merits such as low density, abrasion resistance, impact resistance, permanent flame retardance etc. Current research at home and abroad is mainly on the manufacturing process, mechanical and electrical properties of aramid fibers while the sound absorption property research is less. We prepared aramid micro-perforated composite materials according to the theory of micro-perforated absorber, in order to test and analyse sound absorption properties of micro-perforated sound-absorbing materials with different thickness, aperture, perforation ratio and combined program by using acoustic standing wave tube measurement system. Experimental results show that: the absorption effect of the Micro-perforated Panel Aramid Composite is obvious, in a certain frequency; the absorption coefficient is greatly improved. The study offers a new method for aramid fibers which could be applied in planes and cars.
Improved Dynamic Process Neural Network and its Application
Authors: Zhang Pei Yin , Yu G.B. , Dai B. , Ao Ying Jie
Published: December 2010

The tourism demand is essential in terms of national economy and the improvement of
people’ income. But it is difficult for traditional methods to predict the tendency of the tourism
demand. In this paper, a time series prediction method based on dynamic process neural network
(DPNN) is proposed to solve this problem. An improved particle swarm optimization (IPSO) is
developed. By tuning the structure and improving the connection weights of PNN simultaneously, a
partially connected DPNN can be obtained. The effectiveness of the proposed DPNN is proved by
Henon system. Finally, the proposed DPNN is utilized to predict the tourism demand, and the test
results indicate that the proposed model seems to perform well and appears suitable for using as a
predictive maintenance tool.