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Sample records for austempered ductile iron

  1. Austempered Ductile Iron Machining

    Science.gov (United States)

    Pilc, Jozef; Šajgalík, Michal; Holubják, Jozef; Piešová, Marianna; Zaušková, Lucia; Babík, Ondrej; Kuždák, Viktor; Rákoci, Jozef

    2015-12-01

    This article deals with the machining of cast iron. In industrial practice, Austempered Ductile Iron began to be used relatively recently. ADI is ductile iron that has gone through austempering to get improved properties, among which we can include strength, wear resistance or noise damping. This specific material is defined also by other properties, such as high elasticity, ductility and endurance against tenigue, which are the properties, that considerably make the tooling characteristic worse.

  2. Austempered ductile iron process development

    Science.gov (United States)

    Gupta, C. D.; Keough, J. R.; Pramstaller, D. M.

    1986-11-01

    Pressure from imports and material substitution has severly affected demand for domestic iron industry products. It is estimated that the potential market for Austempered Ductile Iron (ADI) is as large as the market for carburized and/or through hardened forgings. The primary interest in ADI is generated by the economics of process. Improved machinability and reduced processing costs as well as interesting physical properties has created an enormous interest in all metalworking industries towards ADI. The development of gas-fired austempering processes and resoluton of technical and economic uncertainities concerning the process will help improve the outlook for iron founderies.

  3. Properties investigation of austempered ductile iron

    OpenAIRE

    Sudhanshu Detwal; Deivanathan R

    2016-01-01

    This work concerns microstructural and mechanical properties of an austempered ductile cast iron (ADI). The ductile iron material was produced by the sand mould casting technique. Afterwards, austempering heat treatment was applied to the specimens at two different temperatures of 250°C and 350°C. Austempered Ductile Irons (ADIs) were produced successfully by different two-stage heat treatments, to obtain favorable microstructure and hardness. The microstructure and hardness obtained by such ...

  4. Fracture toughness of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, M.N. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering; Komatsu, S. [Kinki Univ., Higashihiroshima (Japan). Dept. of Mechanical Systems Engineering

    1995-12-01

    The effect of austenitizing temperature, austempering temperature and austempering time on the fracture toughness of austempered ductile iron have been presented and discussed in this paper. Statistical design of experiments with a 2{sup 3} matrix was used to determine the effect of the individual variables and their interactions. The desirable combination of the three variables is suggested based on the analysis.

  5. Properties investigation of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Sudhanshu Detwal

    2016-03-01

    Full Text Available This work concerns microstructural and mechanical properties of an austempered ductile cast iron (ADI. The ductile iron material was produced by the sand mould casting technique. Afterwards, austempering heat treatment was applied to the specimens at two different temperatures of 250°C and 350°C. Austempered Ductile Irons (ADIs were produced successfully by different two-stage heat treatments, to obtain favorable microstructure and hardness. The microstructure and hardness obtained by such variable heat treatments were compared. The austempering temperature and time were found to be decisive parameters in obtaining a desired ADI microstructure.

  6. Some Mechanical Properties of Austempered Ductile Iron

    Science.gov (United States)

    Waanders, F. B.; Vorster, S. W.; Vorster, M. J.

    1998-12-01

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a "process window", on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Mössbauer spectra (CEMS) were measured, after heat treatment.

  7. Some mechanical properties of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Waanders, F.B.; Vorster, S.W.; Vorster, M.V. [Potchefstroom Univ. (South Africa). Dept. of Metall. Eng.

    1997-12-01

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a ``process window``, on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Moessbauer spectra (CEMS) were measured, after heat treatment. (orig.). 7 refs.

  8. Some Mechanical Properties of Austempered Ductile Iron

    Energy Technology Data Exchange (ETDEWEB)

    Waanders, F.B.; Vorster, S.W.; Vorster, M.J. [Potchefstroom University, Department of Metallurgical Engineering (South Africa)

    1998-12-15

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a 'process window', on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Moessbauer spectra (CEMS) were measured, after heat treatment.

  9. Thin Wall Austempered Ductile Iron (TWADI

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    M. Górny

    2009-07-01

    Full Text Available In this paper the analysis of thin walled castings made of ductile iron is considered. It is shown that thin wall austempered ductile iron can be obtained by means of short-term heat treatment of thin wall castings without addition of alloying elements. Metallographic examinations of 2 mm thin walled castings along with casting with thicker wall thickness (20x28 mm after different austempring conditions are presented. It has been proved that short-term heat treatment amounted 20 minutes of austenitizing at 880 oC followed by holding at 400 oC for 5 minutes causes ausferrite matrix in 2 mm wall thickness castings, while casting with thicker wall thickness remain untransformed and martensite is still present in a matrix. Finally there are shown that thin wall ductile iron is an excellent base material for austempering heat treatments. As a result high mechanical properties received in thin wall plates made of austempered ductile iron.

  10. Thin wall ductile and austempered iron castings

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2010-07-01

    Full Text Available It has been shown that it is possible to produce thin wall castings made of ductile iron with wall thickness in the range of 1.2 to 2.9 mm(without chills, cold laps and misruns. Thin wall ductile iron castings can be lighter (380 g than their substitutes made of aluminium alloys (580g. The kinetics of austenitising transformation was studied in unalloyed ductile iron. The advance of transformations during austenitising was monitored by measurement the fraction of martensite and also by dilatometic studies. It has been shown that in thin wall ductile iron castings austenitising at 880 oC for 20 minutes is adequate to obtain the austenite matrix at the end of the first stage of austempering heat treatment cycle.

  11. Thin Wall Austempered Ductile Iron (TWADI)

    OpenAIRE

    M. Górny; E. Fraś

    2009-01-01

    In this paper the analysis of thin walled castings made of ductile iron is considered. It is shown that thin wall austempered ductile iron can be obtained by means of short-term heat treatment of thin wall castings without addition of alloying elements. Metallographic examinations of 2 mm thin walled castings along with casting with thicker wall thickness (20x28 mm) after different austempring conditions are presented. It has been proved that short-term heat treatment amounted 20 minutes of a...

  12. Abrasive wear behaviour of as cast and austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Baydogan, M.; Koekden, M.U.; Cimenoglu, H. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Science Engineering Istanbul (Turkey)

    2000-07-01

    In this study, abrasive wear behaviour of as cast and austempered GGG 50 and GGG 80 quality ductile irons was investigated. In the as cast condition, GGG 50 and GGG 80 quality ductile irons were having ferritic and pearlitic matrix structures, respectively. Austempering at 250 C after austenitisation at 900 C for 100 minutes produced bainitic matrix structure in both of the investigated ductile irons. Abrasive wear tests performed by rubbing the as cast and austempered specimens on Al{sub 2}O{sub 3} abrasive bands, revealed that austempering treatment improves abrasion resistance about 10-70% depending on the abrasive particle size and composition of the base iron. In the as cast condition, pearlitic GGG 80 grade ductile iron, has higher wear resistance than ferritic GGG 50 grade ductile iron. In the austempered condition GGG 50 and GGG 80 grade ductile irons which have bainitic matrix structure, exhibit almost similar wear resistance. (orig.)

  13. The austempering study of alloyed ductile iron

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    Eric, Olivera [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)]. E-mail: oliverae@vin.bg.ac.yu; Jovanovic, Milan [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro); Sid-baranin, Leposava [University of Novi Sad, Faculty of Technical Sciences, Novi Sad (Serbia and Montenegro); Rajnovic, Dragan [University of Novi Sad, Faculty of Technical Sciences, Novi Sad (Serbia and Montenegro); Zec, Slavica [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)

    2006-07-01

    Austempered ductile iron (ADI) proved to be an excellent material as it possesses attractive properties: high strength, ductility and toughness are combined with good wear resistance and machinability. These properties can be achieved upon adequate heat treatment which yields optimum microstructure for a given chemical composition. In this paper an investigation has been conducted on ADI alloyed with 0.45%Cu and austempered in a range of times and temperatures. The microstructure and fracture mode developed throughout these treatments have been identified by means of light and scanning electron microscopy and X-ray diffraction analysis. It was shown that strength, elongation and impact energy strongly depend on amounts of bainitic ferrite and retained austenite. Based on these results an optimal processing window has been established.

  14. Calorimetric examinations of austempered ductile iron ADI

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    F. Binczyk

    2007-12-01

    Full Text Available The study presents the results of calorimetric examinations during heating and cooling of austempered ductile iron ADI after austempering at temperatures of 280, 330 and 380oC. The samples for examinations were taken from cast rods of 20 and 60 mm diameter. Examinations were carried out on a differential scanning calorimeter, type Multi HTC S60. During heating, on a DSC curve one strong exothermic effect has been noted to occur (it does not occur in the case of common-grade cast iron, accompanied by two endothermic effects. The exothermic effect occurs within the range of about 20oC. Depending on the temperature of austempering treatment, its beginning falls to the temperatures from 469 to 490oC. The heat of this effect is proportional to the austenite content in ADI matrix after austempering. The endothermic effects are related with decomposition of pearlite (or bainite and with phase transformation α → γ (ferrite as a constituent of ausferritic matrix.

  15. Stacking faults in austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Hermida, J.D. [CNEA, San Martin (Argentina). Dept. de Materiales

    1996-06-01

    During last decade, Austempered Ductile Iron (ADI) has been successfully used as an acceptable replacement material for steel in many applications, due to the relatively high strength and reasonable ductility obtained. These properties are the result of the special microstructure exhibited by this material at the end of the upper bainite reaction: ferrite platelets surrounded by high carbon stabilized austenite. However, at the beginning of the austempering treatment, the existence of interdendritic low carbon austenite is revealed by its transformation to martensite when cooling the sample or during subsequent deformation. The completion of the upper bainite reaction is of decisive importance to mechanical properties because the remaining martensite reduces ductility. It was observed that the rate of the upper bainite reaction is governed by the carbon content difference between the low and high carbon austenites. The carbon content is obtained by the lattice parameter measurement, because there exists a known expression that relates both magnitudes. Several works have used X-ray diffraction to measure the lattice parameter and phase concentrations as a function of austempering time. In these works, the lattice parameters were obtained directly from the {l_brace}220{r_brace} and {l_brace}311{r_brace} peaks position. The purpose of this work is to show more precise lattice parameters measurement and, very closely related to this, the existence of stacking faults in austenite, even at times within the processing window.

  16. Tensile properties of copper alloyed austempered ductile iron: Effect of austempering parameters

    Science.gov (United States)

    Batra, U.; Ray, S.; Prabhakar, S. R.

    2004-10-01

    A ductile iron containing 0.6% copper as the main alloying element was austenitized at 850 °C for 120 min and was subsequently austempered for 60 min at austempering temperatures of 270, 330, and 380 °C. The samples were also austempered at 330 °C for austempering times of 30 150 min. The structural parameters for the austempered alloy austenite (X γ ), average carbon content (C γ ), the product X γ C γ , and the size of the bainitic ferrite needle (d α ) were determined using x-ray diffraction. The effect of austempering temperature and time has been studied with respect to tensile properties such as 0.2% proof stress, ultimate tensile strength (UTS), percentage of elongation, and quality index. These properties have been correlated with the structural parameters of the austempered ductile iron microstructure. Fracture studies have been carried out on the tensile fracture surfaces of the austempered ductile iron (ADI).

  17. Neural Network Analysis of Tensile Strength of Austempered Ductile Iron

    OpenAIRE

    Z. Ławrynowicz; S. Dymski; M. Trepczyńska - Łent; T. Giętka

    2007-01-01

    The neural technique was applied to the analysis of the ultimate tensile strength and additionally the yield strength of austempered ductile iron (ADI). Austempered ductile iron is an excellent material and it possesses attractive properties as high strength, ductility and toughness. This paper begins with an introduction to neural networks and demonstrates the ability of the method to investigate new phenomena in cases where the information cannot be accessed experimentally. The model allows...

  18. Wear resistance properties of austempered ductile iron

    Science.gov (United States)

    Lerner, Y. S.; Kingsbury, G. R.

    1998-02-01

    A detailed review of wear resistance properties of austempered ductile iron (ADI) was undertaken to examine the potential applications of this material for wear parts, as an alternative to steels, alloyed and white irons, bronzes, and other competitive materials. Two modes of wear were studied: adhesive (frictional) dry sliding and abrasive wear. In the rotating dry sliding tests, wear behavior of the base material (a stationary block) was considered in relationship to countersurface (steel shaft) wear. In this wear mode, the wear rate of ADI was only one-fourth that of pearlitic ductile iron (DI) grade 100-70-03; the wear rates of aluminum bronze and leaded-tin bronze, respectively, were 3.7 and 3.3 times greater than that of ADI. Only quenched DI with a fully martensitic matrix slightly outperformed ADI. No significant difference was observed in the wear of steel shafts running against ADI and quenched DI. The excellent wear performance of ADI and its countersurface, combined with their relatively low friction coefficient, indicate potential for dry sliding wear applications. In the abrasive wear mode, the wear rate of ADI was comparable to that of alloyed hardened AISI 4340 steel, and approximately one-half that of hardened medium-carbon AISI 1050 steel and of white and alloyed cast irons. The excellent wear resistance of ADI may be attributed to the strain-affected transformation of high-carbon austenite to martensite that takes place in the surface layer during the wear tests.

  19. Nondestructive Evaluation of the Austempered Ductile Cast Irons

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    Lee, S. S.; Lee, S. K. [Korea Standards Research Institute, Daejeon (Korea, Republic of)

    1989-05-15

    Austempered ductile cast iron (ADI) which has been recently developed shows good mechanical properties. These properties are related to the microstructure which is greatly affected by processing variables such as austempering time and temperature. In this study, the relationships between mechanical properties from impact test, and hardness test and the results from ultrasonic velocity measurement and electrical resistivity measurement are studied on the ADI samples which are heat treated at different austempering temperature and time. From the results, we conclude the followings. The ultrasonic velocity measurement could be used for the study of austempering reaction mechanism. The electrical resistivity measurement could be used as quality assurance technique for the ADI

  20. Effect of fully and semi austempering treatment on the fatigue properties of ductile cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Gun; Lim, Bok Kyu; Hwang, Jung Gak [Kangwon National Univ., Chuncheon (Korea, Republic of); Kim, Dong Youl [Samcheok National Univ., Samcheok (Korea, Republic of)

    2005-03-01

    Single phase bainite structure which is obtained by the conventional austempering treatment reduces the ductility of ductile cast iron. Because of the reduction of ductility it is possible to worsen the fatigue properties. Therefore, semi austempered ductile iron which is treated from {alpha}+{gamma} is prepared to investigate the static strength and fatigue properties in comparison with fully austempered ductile iron (is treated from {gamma}). In spite of semi austempered ductile iron shows the 86% increase of ductility. Also, semi austempered ductile iron shows the higher fatigue limit and lower fatigue crack growth rate as compared with fully austempered ductile iron. By the fractographical analysis, it is revealed that the ferrite obtained by semi austempering process brings about the plastic deformation (ductile striation) of crack tip and gives the prior path of crack propagation. The relatively low crack growth rate in semi austempered specimen is caused by above fractographical reasons.

  1. Carbon content of austenite in austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Chang, L.C. [Kuang Wu Inst. of Tech. and Commerce, Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering

    1998-06-05

    The development of austempered ductile iron (ADI) is a major achievement in cast iron technology. The austempering heat treatment enables the ductile cast iron containing mainly strong bainitic ferrite and ductile carbon-enriched austenite, with some martensite transforms from austenite during cooling down to room temperature. A key factor controlling the stability of the retained austenite can be evaluated soundly using the thermodynamics principles. It is the purpose here to demonstrate that the data of ADI from numerous sources have a similar trend.

  2. Thermomechanical treatment of austempered ductile iron

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    A. A. Nofal

    2007-11-01

    Full Text Available The production of lightweight ferrous castings with increased strength properties became unavoidable facing the serious challenge of lighter aluminum and magnesium castings. The relatively new ferrous casting alloy ADI offers promising strength prospects, and the thermo-mechanical treatment of ductile iron may suggest a new route for production of thin-wall products. This work aims at studying the influence of thermomechanical treatment, either by ausforming just after quenching and before the onset of austempering reaction or by cold rolling after austempering. In the first part of this work, ausforming of ADI up to 25% reduction in height during a rolling operation was found to add a mechanical processing component compared to the conventional ADI heat treatment, thus increasing the rate of ausferrite formation and leading to a much finer and more homogeneous ausferrite product. The kinetics of ausferrite formation was studied using both metallographic as well as XRD-techniques. The effect of ausforming on the strength was quite dramatic (up to 70% and 50% increase in the yield and ultimate strength respectively. A mechanism involving both a refined microstructural scale and an elevated dislocation density was suggested. Nickel is added to ADI to increase hardenability of thick section castings, while ausforming to higher degrees of deformation is necessary to alleviate the deleterious effect of alloy segregation on ductility. In the second part of this work, the influence of cold rolling (CR on the mechanical properties and structural characteristics of ADI was investigated. The variation in properties was related to the amount of retained austenite (γr and its mechanically induced ransformation. In the course of tensile deformation of ADI, transformation induced plasticity (TRIP takes place, indicated by the increase of the instantaneous value of strain-hardening exponent with tensile strain. The amount of retained austenite was found to

  3. Thermomechanical treatment of austempered ductile iron

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The production of lightweight ferrous castings with increased strength properties became unavoidable hter aluminum and magnesium castings. The relatively new ferrous casting alloy ADI offers promising strength prospects, and the thermo-mechanical treatment of ductile iron may suggest a new fluence of thermomechanical treatment,either by ausforming just after quenching and before the onset of austempering reaction or by cold rolling after of this work, ausforming of ADI up to 25% reduction in height during a rolling operation was found to add a mechanical processing component compared to the conventional ADI heat treatment, thus increasing the rate ics of ausferrite formation was studied using both metallographic as well as XRD-techniques. The effect of ausforming on strength was quite dramatic (up to 70% and 50% increase in the yield and ultimate strength respectively). A mechanism involving both a refined microstructural scale and an elevated dislocation density was suggested. Nickel eformation is necessary to alleviate the deleterious effect of alloy segregation on ductility.luence of cold rolling (CR) on the mechanical properties and structural characteristics ofADI wasinvestigated. The variation in properties was related to the amount of retained austenite nsformation. In the course of tensile deformation of ADI, transformation induced plasticity (TRIP) takes place, indicated by the increase of the instantaneous value of strain-hardening exponent with o partial transformation of γr to martensite under the CR strain. Such strain-induced transformation resulted in higher amounts of mechanically generated therefore increased, while ductility and impact toughness decreased with increasing CR reduction.

  4. Effect of Austempering on Plastic Behavior of Some Austempered Ductile Iron Alloys

    Science.gov (United States)

    Olofsson, Jakob; Larsson, Dan; Svensson, Ingvar L.

    2011-12-01

    A numerical description relating microstructure to elastic and plastic deformation behavior would make it possible to simulate the mechanical behavior of complex cast components with tailored material properties. Limited work and data, however, have been published regarding the connection between microstructure and plastic behavior of austempered ductile irons (ADIs). In the current work, the effects of austempering temperature and austempering time on the strength coefficient and the strain hardening exponent of the Hollomon equation were investigated for two ADI alloys. The results show that the plastic behavior is highly dependent on the combination of austempering temperature and austempering time. It was found that as the austempering temperature increases, both the strength coefficient and the strain hardening exponent initially decrease, but after reaching a minimum at the critical austempering temperature, they show a plateau or an increase. The effect of the austempering time on the plastic behavior depends on the austempering temperature. At low austempering temperatures, the strength coefficient and the strain hardening exponent decrease with increased austempering time, whereas at higher austempering temperatures, they show little time dependence. These relations are explained by the microstructural transformations that take place during the austempering heat treatment.

  5. Neutron diffraction study of austempered ductile iron

    Science.gov (United States)

    Choi, C. S.; Sharpe, W.; Barker, J.; Fields, R. J.

    1996-04-01

    Crystallographic properties of an austempered ductile iron (ADI) were studied by using neutron diffraction. A quantitative phase analysis based on Rietveld refinements revealed three component phases, α-Fe (ferrite), γ-Fe (austenite), and graphite precipitate, with weight fractions of 66.0, 31.5, and 2.5 pct, respectively. The ferrite phases of the samples were found to be tetragonal, 14/mmm, with a c/a ratio of about 0.993, which is very close to the body-centered cubic (bcc) structure. The austenite phase had C atoms occupying the octahedral site of the face-centered cubic (fcc) unit cell with about 8 pct occupancy ratio. A strong microstrain broadening was observed for the two Fe phases of the samples. The particle sizes of the acicular ferrite phase were studied by using small angle neutron scattering. The analysis suggested a mean rod diameter of 700 A. The scattering invariant predicts a ferrite volume fraction consistent with the powder diffraction analysis. A textbook case of nodular graphite segregation, with average diameters ranging from 10 to 20 μm, was observed by optical micrography.

  6. Effect of Austempering on Plastic Behavior of Some Austempered Ductile Iron Alloys

    OpenAIRE

    Olofsson, Jakob; Larsson, Dan; Svensson, Ingvar L

    2011-01-01

    A numerical description relating microstructure to elastic and plastic deformation behavior would make it possible to simulate the mechanical behavior of complex cast components with tailored material properties. Limited work and data have however been published regarding the connection between microstructure and plastic behavior of austempered ductile irons (ADI). In the current work the effects of austempering temperature and austempering time on the strength coefficient and the strain hard...

  7. Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI) samples

    OpenAIRE

    Savićević, S.; Avdušinović, H.; A. Gigović-Gekić; Z. Jurković; Vukčević, M.; M. Janjić

    2017-01-01

    Austempered Ductile Iron (ADI) is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In...

  8. Experimental study of the thermal stability of austempered ductile irons

    Science.gov (United States)

    Pérez, M. J.; Cisneros, M. M.; Valdés, E.; Mancha, H.; Calderón, H. A.; Campos, R. E.

    2002-10-01

    A nonisothermal annealing was applied to austempered Ni-Cu-Mo alloyed and unalloyed ductile irons to determine the thermal stability of the ausferritic structure. Differential thermal analysis (DTA) results were used to build the corresponding stability diagrams. The transformation starting temperature of the high carbon austenite was found to be strongly dependent on the austempering temperature, the heating rate, and the chemical composition of the iron. The Ni-Cu-Mo alloying elements and high austempering temperature increased the stability. The transformation of the austenite to ferrite and cementite is achieved via the precipitation of transition carbides identified as silico-carbides of triclinic structure.

  9. Successive Boronizing and Austempering for GGG-40 Grade Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    Murat Baydogan; Seckin Izzet Akray

    2009-01-01

    Boronizing and austempering were successively applied to a GGG-40 grade ductile iron in order to combine the advantages of both process in a single treatment. This new procedure formed a 30 μm thick boride layer on the surface with subsurface matrix structure consisted of acicular ferrite and retained austenite. Reciprocating wear tests showed that successive boronizing and austempering exhibited considerably higher wear resistance than conventional boronizing having a subsurface matrix structure consisting of ferrite and pearlite.

  10. Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI samples

    Directory of Open Access Journals (Sweden)

    S. Savićević

    2017-01-01

    Full Text Available Austempered Ductile Iron (ADI is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In this paper, an investigation of the influence of the austempering temperature on the tensile strength of the ADI samples is presented.

  11. APPLICATION OF AUSTEMPERED DUCTILE IRON TO RAIL WHEEL SETS

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    Sacit DÜNDAR

    2003-03-01

    Full Text Available Austempered Ductile Iron (ADI is made up of a composite structure of acicular ferrite and carbon-enriched austenite. The transformation of austenite to martensite under certain stress levels results in a material with a hard rim and a tough internal structure. These properties makes it an alternate material for the production of railcar wheelsets.

  12. APPLICATION OF AUSTEMPERED DUCTILE IRON TO RAIL WHEEL SETS

    OpenAIRE

    Sacit DÜNDAR

    2003-01-01

    Austempered Ductile Iron (ADI) is made up of a composite structure of acicular ferrite and carbon-enriched austenite. The transformation of austenite to martensite under certain stress levels results in a material with a hard rim and a tough internal structure. These properties makes it an alternate material for the production of railcar wheelsets.

  13. The surface layer of austempered ductile iron investment castings properties

    OpenAIRE

    D. Myszka; M. Kłębczyk; Zych, A.; L. Kwiatkowski

    2009-01-01

    The article presents a unique process of carbonnitriding and nitriding the precision casting surfaces of austempered ductile iron. The results of the research are pointing that adequate process parameters allow to obtain multiple increase of wear resistance and a significant increase of corrosion resistance. Also, changes of cast microstructure and hardness are presented.

  14. Wear and scuffing of austempered ductile iron gears

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, L. [Departamento de Engenharia Mecanica, Instituto Superior de Engenharia, Instituto Politecnico do Porto (Portugal); Seabra, J. [Porto Univ. (Portugal). Dept. Engenharia Mecanica e Gestao Industrial

    1998-03-01

    This paper enhances actual knowledge of the properties of austempered ductile iron (ADI) as a gear material. Results from scuffing tests performed with ADI gears on a FZG test rig are presented and discussed. Contact condition analysis is done using elast-hydrodynamic theory along with several experimental techniques, as surface electronic scanning microscopy, metallurgical spectroscopy and lubricant ferrographic analysis. (orig.)

  15. The surface layer of austempered ductile iron investment castings properties

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2009-01-01

    Full Text Available The article presents a unique process of carbonnitriding and nitriding the precision casting surfaces of austempered ductile iron. The results of the research are pointing that adequate process parameters allow to obtain multiple increase of wear resistance and a significant increase of corrosion resistance. Also, changes of cast microstructure and hardness are presented.

  16. Influence of microstructure on fracture toughness of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.P.; Putatunda, S.K. [Wayne State Univ., Detroit, MI (United States). Dept. of Chemical Engineering and Materials Science

    1997-07-01

    An investigation was carried out to examine the influence of microstructure on the plane strain fracture toughness of austempered ductile iron. Austempered ductile iron (ADI) alloyed with nickel, copper, and molybdenum was austenitized and subsequently austempered over a range of temperatures to produce different microstructures. The microstructures were characterized through optical microscopy and X-ray diffraction. Plane strain fracture toughness of all these materials was determined and was correlated with the microstructure. The results of the present investigation indicate that the lower bainitic microstructure results in higher fracture toughness than upper bainitic microstructure. Both volume fraction of retained austenite and its carbon content influence the fracture toughness. The retained austenite content of 25 vol pct was found to provide the optimum fracture toughness. It was further concluded that the carbon content of the retained austenite should be as high as possible to improve fracture toughness.

  17. Thin wall ductile and austempered iron castings

    OpenAIRE

    E. Fraś; M. Górny

    2010-01-01

    It has been shown that it is possible to produce thin wall castings made of ductile iron with wall thickness in the range of 1.2 to 2.9 mm(without chills, cold laps and misruns). Thin wall ductile iron castings can be lighter (380 g) than their substitutes made of aluminium alloys (580g). The kinetics of austenitising transformation was studied in unalloyed ductile iron. The advance of transformations during austenitising was monitored by measurement the fraction of martensite and also by dil...

  18. Dry sliding wear of Ni alloyed austempered ductile iron

    Directory of Open Access Journals (Sweden)

    E. Akbarzadeh Chiniforush

    2016-09-01

    Full Text Available Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si-0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 °C after austenitizing at 870 °C for 120 min. The mechanical property measurements show that the grades of the ASTM 897M: 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.

  19. Wear Behavior of Austempered Ductile Iron with Nanosized Additives

    Directory of Open Access Journals (Sweden)

    J. Kaleicheva

    2014-03-01

    Full Text Available The microstructure and properties of austempered ductile iron (ADI strengthened with nanosized addtives of titanium nitride + titanium carbonitride (TiN + TiCN, titanium nitride TiN and cubic boron nitride cBN are investigated. The TiN, TiCN and cBN, nanosized particles are coated by electroless nickel coating EFTTOM-NICKEL prior to the edition to the melt. The spheroidal graphite iron samples are undergoing an austempering, including heating at 900 оС for an hour, after that isothermal retention at 280 оС, 2 h and 380 оС, 2h. The metallographic analysis by optical metallographic microscope GX41 OLIMPUS and hardness measurements by Vickers Method are performed. The structure of the austempered ductile iron consists of lower bainite and upper bainite.Experimental investigation of the wear by fixed abrasive are also carried out. The influence of the nanosized additives on the microstructure, mechanical and tribological properties of the austempered ductile irons (ADI is studied.

  20. Production of austempered ductile iron gears for transmission cases

    Energy Technology Data Exchange (ETDEWEB)

    Sagin, A. [Metallurgy Engineering Dept., Technical Univ. of Yildiz, Istanbul (Turkey); Topuz, A. [Chemical and Metallurgical Faculty, Technical Univ. of Yildiz, Istanbul (Turkey)

    2005-07-01

    The investigations presented in this contribution were targeted to replace a gear group made up of SAE 8620 steel in army jeeps with microstructural controlled austempered ductile iron, in order to reduce the manufacturing steps. Furthermore, the vibrations were also expected to decrease, due to the application of austempered ductile iron. The fatigue resistance of unalloyed and Ni alloyed austempered ductile iron have been investigated to see if some improvement as compared to steels with cementite could be achieved. The effect of the austenization heat treatment on the fatigue resistance was studied in metallographic investigations and it turned out that the alloying elements Cu, Ni and Mo have a beneficial effect. For economical reasons, the gears were fabricated of nodular iron containing 3.98% C, 1.89% Si, 0.269% Mn and 0.028% P. Considering the fatigue resistance, a Ni alloyed material with 3.66% C, about 1.81% Si, 0.134% Mn, 0.031% P and 1.51% Ni was chosen. The roundness of the graphites was about 93-100% and 80-85%. The gears were at first produced by austenization at 900 C for 3 hours and then by austempering at 235 C for 2.5 hours. The fatigue tests were performed at the maximum stresses to be expected. (orig.)

  1. Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

    Science.gov (United States)

    Li, X. H.; Saal, P.; Gan, W. M.; Landesberger, M.; Hoelzel, M.; Hofmann, M.

    2016-09-01

    The strain induced martensitic transformation in austempered ductile iron (ADI) has been investigated using high resolution neutron diffraction on samples compressed ex-situ to different plastic strains. In addition bulk texture measurements using neutron diffraction have been performed to calculate the orientation distribution of ferrite and austenite phases for different strain levels. Combing the detailed texture information with neutron diffraction pattern proved to be essential for quantitative phase analysis and extraction of martensite phase fractions. The martensite content induced by strain in ADI depends on austempering temperature and degree of deformation.

  2. Neural Network Analysis of Tensile Strength of Austempered Ductile Iron

    Directory of Open Access Journals (Sweden)

    Z. Ławrynowicz

    2007-07-01

    Full Text Available The neural technique was applied to the analysis of the ultimate tensile strength and additionally the yield strength of austempered ductile iron (ADI. Austempered ductile iron is an excellent material and it possesses attractive properties as high strength, ductility and toughness. This paper begins with an introduction to neural networks and demonstrates the ability of the method to investigate new phenomena in cases where the information cannot be accessed experimentally. The model allows the strength properties to be estimated as a function of heat treatment parameters and the chemical composition. A ‘committee’ model was used to increase the accuracy of the predictions. The model was validated by comparison its predictions with data of tensile tests experiments on austempered samples of ductile cast iron. The model successfully reproduces experimentally determined ultimate tensile strength and it can be exploited in the predictions of both ultimate and yield strength and in the design of chemical composition of cast irons and their heat treatments.

  3. Mechanical properties and structure of austempered ductile iron -ADI

    Directory of Open Access Journals (Sweden)

    Krzyńska A.

    2007-01-01

    Full Text Available The results of experimental study of austempered ductile iron are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with 500 7 grade ductile iron, which was austempered using different parameters of heat treatment. The specimens were first solution treated 1 hour in 910oC and then isothermally quenched for different time in silicon oil bath of temperature 275, 325, 300 and 350oC. The mechanical properties heat treated specimens were tested in tensile to evaluate yield stress Re, 0.2, tensile strength Rm and elongation A10. Additionally hardness of heat treated samples was measured using Brinell-Rockwell hardness tester. Structure of the specimens was studied either with conventional metallography, scanning (SEM and transmission (TEM electron microscopy. It followed from the study that conventional grade ductile iron enabled to produce both low and high strength ADI, depend on heat treatment parameters. As expected the low temperature isothermal quenching produced higher strength ADI compare to the same ductile iron but austempered at 350oC. It was discovered however, that low yield strength ADI obtained for short time quenching at 275oC exhibited high strengthening effect while strained in tensile. So it was concluded that this had to by cause by large amount of untransformed austenite, which FCC lattice is characterized by high strengthening coefficient.

  4. Tensile properties of austempered ductile iron under thermomechanical treatment

    Science.gov (United States)

    Achary, J.

    2000-02-01

    A new processing method was investigated for improving the strength and elongation of austempered ductile iron (ADI) by grain refinement of parent austenite using thermomechanical treatment. The material was deformed at the austenitization temperature by single and multipass rolling before the austempering treatment. The effects of the amount of deformation, austenitization temperature, austempering temperatures, reaustenitization, and secondary deformation on the tensile properties were studied. The properties obtained using the method were compared with those of the ASTM standards. The effect of deformation on the graphite shape was also studied. Tensile strength/yield strength/elongation values were found to increase with increasing austenite deformation up to 40% and then to start decreasing. Tensile strength/yield strength and elongation values of 1700 MPa/1300 MPa/5% and 1350 MPa/920 MPa/15% can be achieved with this method in the ranges of variables studied.

  5. Tensile properties of austempered ductile iron under thermomechanical treatment

    Energy Technology Data Exchange (ETDEWEB)

    Achary, J.

    2000-02-01

    A new processing method was investigated for improving the strength and elongation of austempered ductile iron (ADI) by grain refinement of parent austenite using thermomechanical treatment. The material was deformed at the austenitization temperature by single and multipass rolling before the austempering treatment. The effects of the amount of deformation, austenitization temperature, austempering temperatures, reaustenitization, and secondary deformation on the tensile properties were studied. The properties obtained using the method were compared with those of the ASTM standards. The effect of deformation on the graphite shape was also studied. Tensile strength/yield strength/elongation values were found to increase with increasing austenite deformation up to 40% and then to start decreasing. Tensile strength/yield strength and elongation values of 1,700 MPa/1,300 MPa/5% and 1,350 MPa/920 MPa/15% can be achieved with this method in the ranges of variables studied.

  6. Wear Performance of Cu-Alloyed Austempered Ductile Iron

    Science.gov (United States)

    Batra, Uma; Batra, Nimish; Sharma, J. D.

    2013-04-01

    An investigation was carried out to examine the influence of structural and mechanical properties on wear behavior of austempered ductile iron (ADI). Ductile iron (DI) samples were austenitized at 900 °C for 60 min and subsequently austempered for 60 min at three temperatures: 270, 330, and 380 °C. Microstructures of the as-cast DI and ADIs were characterized using optical and scanning microscopy, respectively. The structural parameters, volume fraction of austenite, carbon content of austenite, and ferrite particle size were determined using x-ray diffraction technique. Mechanical properties including Vicker's hardness, 0.2% proof strength, ultimate tensile strength, ductility, and strain hardening coefficient were determined. Wear tests were carried out under dry sliding conditions using pin-on-disk machine with a linear speed of 2.4 m/s. Normal load and sliding distance were 45 N and 1.7 × 104 m, respectively. ADI developed at higher austempering temperature has large amounts of austenite, which contribute toward improvement in the wear resistance through stress-induced martensitic transformation, and strain hardening of austenite. Wear rate was found to depend on 0.2% proof strength, ductility, austenite content, and its carbon content. Study of worn surfaces and nature of wear debris revealed that the fine ausferrite structure in ADIs undergoes oxidational wear, but the coarse ausferrite structure undergoes adhesion, delamination, and mild abrasion too.

  7. Probabilistic assessment of machine parts from Kymenite, austempered ductile iron

    Science.gov (United States)

    Petrova, I.; Galperin, M.; Alimov, M.; Jokipii, K.

    1992-07-01

    The fatigue properties of Kymenite, austempered ductile iron, were investigated on the basis of the statistical theory of fatigue failure similarity. The fatigue tests were carried out on plain and notched specimens. The S-N curves for a given failure probability and the dependencies of similarity equation parameters on the number of cycles were obtained. These data allow to take into consideration the influence of design factors in the fatigue strength.

  8. An austempering study of ductile iron alloyed with copper

    Directory of Open Access Journals (Sweden)

    OLIVERA ERIC

    2005-07-01

    Full Text Available Austempered ductile iron (ADI has proved to be an excellent material as it possesses attractive properties: high strength, ductility and toughness are combined with good wear resistance and machinability. These properties can be achieved upon adequate heat treatment which yields the optimum microstructure for a given chemical composition. In this paper the results of an investigation the austempering of ADI alloyed with 0.45 % Cu for a range of times and temperatures are reported. The microstructure and fracture mode developed throughout these treatments have been identified by means of light and scanning electron microscopy and X-ray diffraction analysis. It was shown that the strength, elongation and impact energy strongly depend on the amounts of bainitic ferrite and retained austenite. Based on these results, and optimal processing window was established.

  9. Superior austempered ductile iron (ADI) properties achieved by prior hot isostatic pressing (HIP)

    Energy Technology Data Exchange (ETDEWEB)

    LaGoy, J.L.; Widmer, R.; Zick, D.H. [Industrial Materials Technology Inc., Andover, MA (United States)

    1996-12-31

    Ductile iron obtained from different foundries and cast by dissimilar methods has been successfully hot isostatically pressed (HIPed) before austempering to achieve substantially higher ductilities, without significant detriment to other properties, than those reached by austempering along. HIP was attempted to solve different mechanical deficiencies in austempered ductile iron (ADI) such as the lack of ductility in higher strength grades, inconsistent mechanical properties, and service life limitations. A variety of HIP temperatures were analyzed from near the austenitizing region up to within 56 C (100 F) of the melting point of ductile iron. Microporosity was eliminated by HIP at all temperatures, and subsequent austempering revealed a uniform ADI microstructure. HIP proved successful with both unencapsulated castings and those enclosed within steel canisters. Additional benefits caused by HIP processing of ductile iron castings without the austempering treatment include a significant decrease in mechanical property data scatter, high hardness at reasonable ductility levels, and a substantially reduced scrap rate.

  10. Austempering kinetics of Cu-Ni alloyed austempered Ductile Iron

    Science.gov (United States)

    Cekic, Olivera Eric; Sidjanin, Leposava; Rajnovic, Dragan; Balos, Sebastian

    2014-11-01

    The aim of the paper was to investigate the effect of austempering parameters (time and temperature) on the microstructure and mechanical properties of ADI alloyed with 1.5% Cu and 1.6% Ni (in wt.%) in order to establish the optimal processing window. It was shown that the strength, elongation and impact energy strongly depend on the amounts of ausferritic ferrite and retained austenite. A processing window was established according to the results of the kinetics of the isothermal transformation. The results show that the processing window for ADI alloyed with Cu and Ni at 350 °C was relatively wide, while the processing window for the isothermal transformation at 400 °C becomes narrower and shifted to the left. The processing window of ADI austempered at 300 °C is also narrower, but shifted to the right towards the longer times compared to the processing window of ADI austempered at 350 °C.

  11. Microstructure evolution during surface alloying of ductile iron and austempered ductile iron by electron beam melting

    Science.gov (United States)

    Gulzar, A.; Akhter, J. I.; Ahmad, M.; Ali, G.; Mahmood, M.; Ajmal, M.

    2009-07-01

    Alloying and microstructural modification of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modification of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve the surface properties. Martensitic structure evolved in the heat affected zone and ledeburite structure was produced in the molten zone of the ductile iron. Microhardness of the melted specimens enhanced considerably as compared to the as-received samples. However the microhardness of melted Ni-plated samples is lower than that of the unplated specimens. X-ray diffraction clearly revealed the formation of an austenite and Fe 3C phases in the electron beam molten zone. The broadening of peaks suggests refinement of the microstructure as well as internal stresses generated during electron beam melting.

  12. Microstructure evolution during surface alloying of ductile iron and austempered ductile iron by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Gulzar, A. [Materials Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Akhter, J.I. [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Ahmad, M., E-mail: maqomer@yahoo.com [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Ali, G. [Physics Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad (Pakistan); Mahmood, M. [Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan); Ajmal, M. [Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore (Pakistan)

    2009-07-30

    Alloying and microstructural modification of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modification of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve the surface properties. Martensitic structure evolved in the heat affected zone and ledeburite structure was produced in the molten zone of the ductile iron. Microhardness of the melted specimens enhanced considerably as compared to the as-received samples. However the microhardness of melted Ni-plated samples is lower than that of the unplated specimens. X-ray diffraction clearly revealed the formation of an austenite and Fe{sub 3}C phases in the electron beam molten zone. The broadening of peaks suggests refinement of the microstructure as well as internal stresses generated during electron beam melting.

  13. Integrated modeling and heat treatment simulation of austempered ductile iron

    Science.gov (United States)

    Hepp, E.; Hurevich, V.; Schäfer, W.

    2012-07-01

    The integrated modeling and simulation of the casting and heat treatment processes for producing austempered ductile iron (ADI) castings is presented. The focus is on describing different models to simulate the austenitization, quenching and austempering steps during ADI heat treatment. The starting point for the heat treatment simulation is the simulated microstructure after solidification and cooling. The austenitization model considers the transformation of the initial ferrite-pearlite matrix into austenite as well as the dissolution of graphite in austenite to attain a uniform carbon distribution. The quenching model is based on measured CCT diagrams. Measurements have been carried out to obtain these diagrams for different alloys with varying Cu, Ni and Mo contents. The austempering model includes nucleation and growth kinetics of the ADI matrix. The model of ADI nucleation is based on experimental measurements made for varied Cu, Ni, Mo contents and austempering temperatures. The ADI kinetic model uses a diffusion controlled approach to model the growth. The models have been integrated in a tool for casting process simulation. Results are shown for the optimization of the heat treatment process of a planetary carrier casting.

  14. Neutron Diffraction Studies of Intercritically Austempered Ductile Irons

    Energy Technology Data Exchange (ETDEWEB)

    Druschitz, Alan [University of Alabama, Birmingham; Aristizabal, Ricardo [University of Alabama, Birmingham; Druschitz, Edward [University of Alabama, Birmingham; Hubbard, Camden R [ORNL; Watkins, Thomas R [ORNL

    2011-01-01

    Neutron diffraction is a powerful tool that can be used to identify the phases present and to measure the spacing of the atomic planes in a material. Thus, the residual stresses can be determined within a component and/or the phases present. New intercritically austempered irons rely on the unique properties of the austenite phase present in their microstructures. If these materials are to see widespread use, methods to verify the quality (behavior consistency) of these materials and to provide guidance for further optimization will be needed. Neutron diffraction studies were performed at the second generation neutron residual stress facility (NRSF2) at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory on a variety of intercritically austempered irons. For similar materials, such as TRIP steels, the strengthening mechanism involves the transformation of metastable austenite to martensite during deformation. For the intercritically austempered ductile irons two different deformation/strengthening mechanisms, phase transformation and slip, dependent upon the iron chemistry, were observed. Lattice strain and phase fraction data as a function of applied stress are presented.

  15. Effect of alloying elements on austempered ductile iron (ADI) properties and its process: Review

    OpenAIRE

    Amir Sadighzadeh Benam

    2015-01-01

    Austempered ductile iron (ADI) parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the...

  16. Bending Fatigue Strength of Austempered Ductile Iron Spur Gears

    Science.gov (United States)

    Yamanaka, Masashi; Tamura, Ryo; Inoue, Katsumi; Narita, Yukihito

    This paper deals with an experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears. The module is 2.5 and the number of teeth is 26 in the test gears. The material of the test gears corresponds to Japan Industrial Standard (JIS) FCAD1100-15. Some gears are processed by one of two types of fine particle bombarding (FPB). The surface roughness is slightly increased by FPB. The obtained strengths are 623 MPa for the as-austempered gears, and 1011 and 1085 MPa for the gears after FPB. The strength is expressed by the fillet stress level, which is calculated by FEM. The strength of a gear with the same dimensions made of carburized SCr420H alloy steel is 1205 MPa, and the strength of the ADI gear is approximately half that of the carburized steel gear. The FPB process has a significant effect on the ADI gear, improving its strength by 62-74%.

  17. A Microscale Model for Ausferritic Transformation of Austempered Ductile Irons

    Science.gov (United States)

    Boccardo, Adrián D.; Dardati, Patricia M.; Celentano, Diego J.; Godoy, Luis A.

    2017-01-01

    This paper presents a new metallurgical model for the ausferritic transformation of ductile cast iron. The model allows predicting the evolution of phases in terms of the chemical composition, austenitization and austempering temperatures, graphite nodule count, and distribution of graphite nodule size. The ferrite evolution is predicted according to the displacive growth mechanism. A representative volume element is employed at the microscale to consider the phase distributions, the inhomogeneous austenite carbon content, and the nucleation of ferrite subunits at the graphite nodule surface and at the tips of existing ferrite subunits. The performance of the model is evaluated by comparison with experimental results. The results indicate that the increment of the ausferritic transformation rate, which is caused by increments of austempering temperature and graphite nodule count, is adequately represented by this model.

  18. Effect of austempering time on mechanical properties of a low manganese austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Putatunda, S.K.; Gadicherla, P.K.

    2000-04-01

    An investigation was carried out to examine the influence of austempering time on the resultant microstructure and the room-temperature mechanical properties of an unalloyed and low manganese ductile cast iron with initially ferritic as-cast structure. The effect of austempering time on the plane strain fracture toughness of this material was also studied. Compact tension and round cylindrical tensile specimens were prepared from unalloyed ductile cast iron with low manganese content and with a ferritic as-cast (solidified) structure. These specimens were then austempered in the upper (371 C) and lower (260 C) bainitic temperature ranges for different time periods, ranging from 30 min. to 3 h. Microstructural features such as type of bainite and the volume fraction of ferrite and austenite and its carbon content were evaluated by X-ray diffraction to examine the influence of microstructure on the mechanical properties and fracture toughness of this material. The results of the present investigation indicate that for this low manganese austempered ductile iron (ADI), upper ausferritic microstructures exhibit higher fracture toughness than lower ausferritic microstructures. Yield and tensile strength of the material was found to increase with an increase in austempering time in a lower bainitic temperature range, whereas in the upper bainitic temperature range, time has no significant effect on the mechanical properties. A retained austenite content between 30 to 35% was found to provide optimum fracture toughness. Fracture toughness was found to increase with the parameter (X{gamma}C{gamma}/d){sup 1/2}, where X{gamma} is the volume fraction of austenite, C{gamma} is the carbon content of the austenite, and d is the mean free path of dislocation motion in ferrite.

  19. Effect of austempering time on mechanical properties of a low manganese austempered ductile iron

    Science.gov (United States)

    Putatunda, Susil K.; Gadicherla, Pavan K.

    2000-04-01

    An investigation was carried out to examine the influence of austempering time on the resultant microstructure and the room-temperature mechanical properties of an unalloyed and low manganese ductile cast iron with initially ferritic as-cast structure. The effect of austempering time on the plane strain fracture toughness of this material was also studied. Compact tension and round cylindrical tensile specimens were prepared from unalloyed ductile cast iron with low manganese content and with a ferritic as-cast (solidified) structure. These specimens were then austempered in the upper (371 °C) and lower (260 °C) bainitic temperature ranges for different time periods, ranging from 30 min. to 4 h. Microstructural features such as type of bainite and the volume fraction of ferrite and austenite and its carbon content were evaluated by X-ray diffraction to examine the influence of microstructure on the mechanical properties and fracture toughness of this material. The results of the present investigation indicate that for this low manganese austempered ductile iron (ADI), upper ausferritic microstructures exhibit higher fracture toughness than lower ausferritic microstructures. Yield and tensile strength of the material was found to increase with an increase in austempering time in a lower bainitic temperature range, whereas in the upper bainitic temperature range, time has no significant effect on the mechanical properties. A retained austenite content between 30 to 35% was found to provide optimum fracture toughness. Fracture toughness was found to increase with the parameter ( XγCγ/d)1/2, where Xγ is the volume fraction of austenite, Cγ is the carbon content of the austenite, and d is the mean free path of dislocation motion in ferrite.

  20. Development of austempered ductile iron timing gears; Austemper kyujo kokuen chutetsu timing gear no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Yamamoto, S.; Numajiri, S.; Nakajima, K. [Mitsubishi Motors Corp., Tokyo (Japan)

    1996-05-01

    To reduce vibration and noise of gears compared with ordinary steel gears for four cycle diesel engine of small commercial vehicles, austempered ductile iron (ADI) gears have been developed, which have excellent mechanical properties and vibration damping properties equivalent to steel gears. ADI is a material with tensile strength of 1,000 MPa, which is made by austempering the ductile iron to change matrix texture into tough bainite. For a new process method of ADI gears, austempering is conducted after gear cutting, and shaving is conducted, finally. Gear materials before austempering can be smoothly machined without deteriorating their machinability, to produce highly accurate gears. Fifteen percent of noise can be reduced for ADI gears during idling of engine, where 0.7 dB can be reduced in the noise level. The ADI gears provide superior pitting resistance to ordinary steel gears. They have nearly equivalent dedendum bending fatigue strength to ordinary soft nitrided steel gears. 6 refs., 12 figs., 2 tabs.

  1. PARAMETER OPTIMIZATION OF CARBIDIC AUSTEMPERED DUCTILE IRON USING TAGUCHI METHOD

    Directory of Open Access Journals (Sweden)

    P.DHANAPAL

    2010-08-01

    Full Text Available Carbidic austempered ductile iron [CADI] is the family of ductile iron containing wear resistance alloy carbides in the ausferrite matrix. This CADI is manufactured by selecting proper material composition through the melting route.In an effort to obtain the optimal production parameters, Taguchi method is applied. To analyse the effect of production parameters on the machanical properties, signal-to-noise (S/N ratio is calculated based on the design ofexperiments and the linear graph. The analysis of varience is calculated to find the amount of contribution of factors on individual mechanical properties and its significancy. The analytical results of taguchi method are compared with the experimental values, and it shows both are identical.

  2. Kinetic Study of the Austempering Reactions in Ductile Irons

    Science.gov (United States)

    Pérez, M. J.; Cisneros, M. M.; Almanza, E.; Haro, S.

    2012-11-01

    Kinetics of the reaction that occur during the austempering heat treatment in unalloyed and alloyed ductile irons with 1Cu-0.25Mo, 1Ni-0.25Mo, and 0.7Cu-1Ni-0.25Mo, was studied. The austenitization and austempering cycles were achieved by isothermal dilatometry in cylindrical samples of 2 mm in diameter and 12 mm in length. The specimens were austenitized at 870 °C for 120 min, followed by isothermal holding for 300 min at temperatures between 270 and 420 °C. Kinetic parameters such as the order of reaction " n" and the rate of reaction " k" were calculated using the Johnson-Mehl equation while the empirical activation energy was calculated by means of the Arrhenius equation. It was found that the values of " k" decreased with the addition of Cu, Ni, and Mo as well as with the reduction of the isothermal temperature. The activation energy changes with the austempering temperature, in the range 30,348-58,250 J/mol when the heat treatment was carried out between 370 and 420 °C and 10,336-26,683 J/mol when the temperature varied from 270 to 350 °C. The microstructures in samples austempered at 370 and 315 °C were observed by transmission electron microscopy. No carbides precipitation was observed on samples heat treated at 370 °C for less than 120 min, while at 315 °C carbides of hexagonal structure ɛ(Fe2.4C) were found from the beginning of the transformation. The smallest value of activation energy and a slower kinetic transformation seem to be related with the presence of a carbide phase. Additionally, the time results obtained for transformation fractions of 0.05 and 0.95 by the dilatometry analysis were used to build the temperature-time-transformation diagrams for the irons.

  3. Effects of various austempering temperatures on fatigue properties in ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Salman, S. [Marmara University, Technical Education Faculty, Istanbul (Turkey); Findik, F. [Materials Technology Department, Technical Education Faculty, Sakarya University, Sakarya (Turkey)]. E-mail: findik@sakarya.edu.tr; Topuz, P. [Yildiz Technical University, Department of Metallurgy and Material, Istanbul (Turkey)

    2007-07-01

    Austempering is an isothermal heat treatment which when applied to ferrous materials, produces a structure that is stronger and tougher than comparable structures produced with conventional heat treatments. In this paper, ductile iron specimens were applied to various austempering temperatures and interpreted fatigue properties. In this test, Denison 7615 fatigue machine was used for doing double sided bending stresses. The iron was austenitized at 900 deg. C and then austempered at 235, 300 and 370 deg. C for 2 h within a salt bath to obtain various austempered microstructures. Also, the fatigue properties of the bainitic structures which occurred by austempering are examined by scanning electron microscope.

  4. Effects of carbides on fatigue characteristics of austempered ductile iron

    Science.gov (United States)

    Stokes, B.; Gao, N.; Reed, P. A. S.; Lee, K. K.

    2005-04-01

    Crack initiation and growth behavior of an austempered ductile iron (ADI) austenitized at 800 °C and austempered at 260 °C have been assessed under three-point bend fatigue conditions. Initiation sites have been identified as carbides remaining from the as-cast ductile iron due to insufficient austenization. The number of carbides cracking on loading to stresses greater than 275 MPa is critical in determining the failure mechanism. In general, high carbide area fractions promote coalescence-dominated fatigue crack failure, while low area fractions promote propagation-dominated fatigue crack failure. Individual carbides have been characterized using finite body tessellation (FBT) and adaptive numerical modeling (Support vector Parsimonious Analysis Of Variance (SUPANOVA)) techniques in an attempt to quantify the factors promoting carbide fracture. This indicated that large or long and thin carbides on the whole appear to be susceptible to fracture, and carbides that are locally clustered and aligned perpendicular to the tensile axis are particularly susceptible to fracture.

  5. Effect of alloying elements on austempered ductile iron (ADI properties and its process: Review

    Directory of Open Access Journals (Sweden)

    Amir Sadighzadeh Benam

    2015-01-01

    Full Text Available Austempered ductile iron (ADI parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the effects of alloying elements on ADI mechanical properties, microstructural changes, two-stage austempering reactions, processing windows, austemperability, and other aspects are reviewed.

  6. CHOSEN FACTORS INFLUENCING MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AUSTEMPERED DUCTILE IRON

    Directory of Open Access Journals (Sweden)

    Alan Vaško

    2009-10-01

    Full Text Available The paper deals with some factors influencing microstructure and mechanical properties of austempered ductile iron (ADI. Final structure and properties of ADI are obtained by exactly controlled process of heat treatment of nodular cast iron. The influence of conditions of isothermal heat treatment on microstructure and mechanical properties of austempered ductile iron, especially different temperature of isothermal transformation of austenite and different holding time at this temperature, is shown in the paper.

  7. CHOSEN FACTORS INFLUENCING MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AUSTEMPERED DUCTILE IRON

    OpenAIRE

    Alan Vaško

    2009-01-01

    The paper deals with some factors influencing microstructure and mechanical properties of austempered ductile iron (ADI). Final structure and properties of ADI are obtained by exactly controlled process of heat treatment of nodular cast iron. The influence of conditions of isothermal heat treatment on microstructure and mechanical properties of austempered ductile iron, especially different temperature of isothermal transformation of austenite and different holding time at this temperature, i...

  8. Effect of austempering temperature on microstructure and mechanical properties of unalloyed ductile iron: Vpliv austempering temperature na mikrostrukturo in mehanske lastnosti nelegirane duktilne sive litine:

    OpenAIRE

    Bošnjak, Branka; Radulović, Branko

    1999-01-01

    Austempered ductile cast iron (ADI) has emerged in the last several decades as a major engeneering material. The heat-treating of the ductile cast iron produces austempered ductile iron (ADI) with an excellent combination of strength, fracture toughness and wear resistance for a wide variety of applications in automotive, rail and heavy engineering industries. The austempering temperature is the most important parameter in determining both the structure and the mechanical properties of unallo...

  9. Microstructures and Mechanical Properties of a Wear-Resistant Alloyed Ductile Iron Austempered at Various Temperatures

    Science.gov (United States)

    Cui, Junjun; Chen, Liqing

    2015-08-01

    To further improve the mechanical performance of a new type of alloyed bainitic wear-resistant ductile iron, the effects of the various austempering temperatures have been investigated on microstructure and mechanical behaviors of alloyed ductile iron Fe-3.50C-1.95Si-3.58Ni-0.71Cu-0.92Mo-0.65Cr-0.36Mn (in weight percent). This alloyed ductile iron were firstly austenitized at 1123 K (850 °C) for 1 hour and then austempered in a salt bath at 548 K, 573 K, and 598 K (275 °C, 300 °C, and 325 °C) for 2 hours according to time-temperature-transformation diagram calculated by JMatPro software. The microstructures of austempered wear-resistant ductile irons consist of matrix of dark needle-like ferrite plus bright etching austenite and some amount of martensite and some dispersed graphite nodules. With increasing the austempering temperature, the amount of ferrite decreases in austempered ductile iron, while the amount of austenite and carbon content of austenite increases. There is a gradual decrease in hardness and increase in compressive strength with increasing austempering temperature. The increased austenite content and coarsened austenite and ferrite can lead to a hardness decrease as austempering temperature is increased. The increased compressive strength can be attributed to a decreased amount of martensitic transformation. The alloyed ductile iron behaves rather well wear resistance when the austempering is carried out at 598 K (325 °C) for 2 hours. Under the condition of wear test by dry sand/rubber wheel, the wear mechanisms of austempered ductile irons are both micro-cutting and plastic deformation.

  10. Kinetics of the Bainite Transformation in Austempered Ductile Iron ADI

    Directory of Open Access Journals (Sweden)

    Ławrynowicz Z.

    2016-06-01

    Full Text Available The aim of the present research is to check an analytical model of the kinetics of bainite transformation that will enable the producers of ADI to optimise the microstructure and mechanical properties and minimise the expensive and extensive experimental trials. A combination of thermodynamics and kinetic theory was used successfully to estimate the evolution of bainite as a function of temperature, time, chemical composition and austenite grain size and predict the processing window in austempered ductile iron using a bainite transformation model developed previously for high silicon steels. The results of the present research show that the bainitic model developed for high silicon steels is applicable for calculations of the processing window for ADI.

  11. FATIGUE CRACK PROPAGATION THROUGH AUSTEMPERED DUCTILE IRON MICROSTRUCTURE

    Directory of Open Access Journals (Sweden)

    Lukáš Bubenko

    2010-10-01

    Full Text Available Austempered ductile iron (ADI has a wide range of application, particularly for castings used in automotive and earth moving machinery industries. These components are usually subjected to variable dynamic loading that may promote initiation and propagation of fatigue cracks up to final fracture. Thus, it is important to determine the fatigue crack propagation behavior of ADI. Since fatigue crack growth rate (da/dN vs. stress intensity factor K data describe fatigue crack propagation resistance and fatigue durability of structural materials, da/dN vs. Ka curves of ADI 1050 are reported here. The threshold amplitude of stress intensity factor Kath is also determined. Finally, the influence of stress intensity factor amplitude to the character of fatigue crack propagation through the ADI microstructure is described.

  12. New Possibilities of Shaping the Surface Properties in Austempered Ductile Iron Castings

    OpenAIRE

    D. Myszka

    2013-01-01

    The paper presents recent developments concerning the formation of surface layer in austempered ductile iron castings. It was found thatthe traditional methods used to change the properties of the surface layer, i.e. the effect of protective atmosphere during austenitising or shot peening, are not fully satisfactory to meet the demands of commercial applications. Therefore, new ways to shape the surface layer and the surface properties of austempered ductile iron castings are searched for, to...

  13. Dependence of fracture toughness of austempered ductile iron on austempering temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.P. [Karnatak Regional Engineering Coll. (India). Dept. of Metallurgical and Materials Engineering; Putatunda, S.K. [Wayne State Univ., Detroit, MI (United States)

    1998-12-01

    Ductile cast iron samples were austenitized at 927 C and subsequently austempered for 30 minutes, 1 hour, and 2 hours at 260 C, 288 C, 316 C, 343 C, 371 C, and 399 C. These were subjected to a plane strain fracture toughness test. Fracture toughness was found to initially increase with austempering temperature, reach a maximum, and then decrease with further rise in temperature. The results of the fracture toughness study and fractographic examination were correlated with microstructural features such as bainite morphology, the volume fraction of retained austenite, and its carbon content. It was found that fracture toughness was maximized when the microstructure consisted of lower bainite with about 30 vol pct retained austenite containing more than 1.8 wt pct carbon. A theoretical model was developed, which could explain the observed variation in fracture toughness with austempering temperature in terms of microstructural features such as the width of the ferrite blades and retained austenite content. A plot of K{sub IC}{sup 2} against {sigma}, (X{sub {gamma}}C{sub {gamma}}){sup 1/2} resulted in a straight line, as predicted by the model.

  14. Dependence of fracture toughness of austempered ductile iron on austempering temperature

    Science.gov (United States)

    Rao, P. Prasad; Putatunda, Susil K.

    1998-12-01

    Ductile cast iron samples were austenitized at 927 °C and subsequently austempered for 30 minutes, 1 hour, and 2 hours at 260 °C, 288 °C, 316 °C, 343 °C, 371 °C, and 399 °C. These were subjected to a plane strain fracture toughness test. Fracture toughness was found to initially increase with austempering temperature, reach a maximum, and then decrease with further rise in temperature. The results of the fracture toughness study and fractographic examination were correlated with microstructural features such as bainite morphology, the volume fraction of retained austenite, and its carbon content. It was found that fracture toughness was maximized when the microstructure consisted of lower bainite with about 30 vol pct retained austenite containing more than 1.8 wt pct carbon. A theoretical model was developed, which could explain the observed variation in fracture toughness with austempering temperature in terms of microstructural features such as the width of the ferrite blades and retained austenite content. A plot of K {/IC 2} against σ y ( X γ, C γ)1/2 resulted in a straight line, as predicted by the model.

  15. Enhancement of Fatigue Properties of Ductile Irons by Successive Austempering Heat Treatment

    Science.gov (United States)

    Jahangiri, M. R.; Ahmadabadi, M. Nili; Farhangi, H.

    2011-12-01

    The aim of this study is to evaluate the effects of austempering heat treatment on the microstructure, mechanical properties, and bending fatigue behavior of an alloyed ductile iron with chemical composition of 1.6 wt.% Ni, 0.47 wt.% manganese and 0.6 wt.% copper. Based on the results of tensile and impact tests, as well as metallographic studies, optimum heat-treating cycles were determined and applied on the standard fatigue specimens. The results showed that the fatigue strength of specimens austempered successively was practically comparable to those austempered at high temperatures and considerably greater than those austempered at low temperatures.

  16. Microstructure transformation during plastic deformation of the austempered ductile iron

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2009-01-01

    Full Text Available Excellent properties of ADI (Austempered Ductile Iron are widely praised by the world technical literature. These properties depend onthe cast iron microstructure formed during the heat treatment process of a specific type. The matrix of ADI is a mixture of lamellar ferrite and high-carbon austenite. It seems, however, that it is the austenite that is responsible for the high strength and ductility of this material, although investigations and analyses have proved that it is not homogeneous. Various types of austenite found in the ADI matrix include unreacted austenite, stable austenite, and metastable austenite which will be transferred into martensite during machining of castings.In this study an attempt has been made to determine the fraction of metastable austenite and to evaluate its effect on ADI properties.The heat treatment enabled manufacturing ADI characterised by the following properties: T.S.>1000MPa, El.>10%, Y.S.>600MPa. As anext step, the controlled process of plastic deformation of the samples was carried out. Applying the new method it has been established that due to 15% cold work, the structure of the examined ADI contains 9% of martensite; this volume fraction goes up to 17% after 25% cold work. The results of the investigations were cofirmed by X-ray diffraction pattern analysis and magnetic measurements.Consequently, it has been proved that ADI characterised by properties satisfying the criteria of an international standard developed for this particular material contains a large amount of metastable austenite subject to the TRIP (Transformation Induced Plasticity effect.

  17. Unnotched Charpy Impact Energy Transition Behavior of Austempered Engineering Grade Ductile Iron Castings

    Science.gov (United States)

    Kisakurek, Sukru Ergin; Ozel, Ahmet

    2014-04-01

    Unnotched Charpy impact energy transition behavior of five different engineering grade ductile iron castings, as specified by EN 1563 Standards, were examined in as-cast, as well as in austempered states. ADIs were produced with the maximum impact energy values permissible for the grades. Austempering treatment detrimented the sub-zero impact properties of the ferritic castings, but considerably enhanced those of the pearlitic-ferritic irons. The impact energy transition behavior of the austempered states of all the grades examined were noted to be determined by the progressive transformation of the unavoidable carbon-unsaturated and untransformed regions of the austenite remaining in the matrix of the austempered ductile iron to martensite with decreasing temperature.

  18. Fundamental Research on Hobbing of Austempered Ductile Iron Gear

    Science.gov (United States)

    Matsuoka, Hironori; Tsuda, Yoshihiro; Ono, Hajime

    In this study, the influence of graphite particles (number of graphite particles) in austempered ductile iron (ADI) on tool wear and finished surface roughness was investigated, using TiN and (Al, Ti)N coated high-speed steel cutting tools in hobbing. The experiments were performed using a fly tool of the same geometry as that of one blade of a hob, at the cutting speed of 47m/min in dry cutting. As a consequence, the following points were clarified: (1) ADI having an average number of 284 graphite particles per 1mm2 (the average diameter of 28.0µm) showed a good machinability without causing tool failure. The tool life was improved when using the (Al, Ti)N coated tool, and the finished surface roughness Ry was 3.5µm at the end of cutting. (2) It was suggested that the adhesion of deposited metal on the rake face influences the tool failure which occurred when cutting ADI. (3) The interrelation between the center wear and the surface roughness was recognized.

  19. Influence of austenization temperature on the erosion behavior of austempered ductile irons

    Institute of Scientific and Technical Information of China (English)

    L.C.Chang; I.C.Hsui; L.H.Chen; S.T.Lui

    2008-01-01

    The erosion behavior of austempered ductile irons austenized at different temperatures was studied. The results indicate that the erosion rate well correlates with the mechanical properties. At high impact angles, increasing ductility and mechanical energy density results in decreasing erosion rate, whereas increasing hardness reduces the erosion rate at low impact angles.

  20. Effect of austempering parameters on microstructure and mechanical properties of horizontal continuous casting ductile iron dense bars

    OpenAIRE

    Chun-jie Xu; Pan Dai; Zheng-yang Zhang

    2015-01-01

    In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters (i.e. austenitizing temperature and time, and austempering temperature and time) on microstructure and mechanical properties of LZQT500-7 ductile iron dense bars with 172 mm in diameter which were produced by horizontal continuous casting (HCC). The results show that the major factors influencing the hardness of austempered ductile iron (ADI) are austeni...

  1. Microstructural and mechanical characteristics of low alloyed Ni-Mo-Cu austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Bosnjak, B.

    2000-12-01

    The present study investigated the effect of austempering temperature and austempering time on the microstructure and mechanical properties of low alloyed Ni-Mo-Cu ductile iron. The effect of austempering parameters and alloying additions on the austemperability of treated ductile iron has been estimated, too. Specimens were austenitised at 900 degree C for 120 mm, then austempered for 10, 30, 60, 120, 240 and 360 mm at 300, 350 and 400 degree C respectively, and examined by light and scanning electron microscopy. The structure consisted of bainitic ferrite containing retained austenite. the amount of which increased, and the carbon content of which decreased, with increasing austempering temperature. The carbon content of austenite has been evaluated by measuring the lattice parameter by X-ray diffraction. After short periods of austempering time in iron, the carbon content of the retained austenite decreases and on subsequent cooling to room temperature it transforms to martensite. The volume fractions of retained austenite, bainitic ferrite, martensite and austenite carbon content was correlated with microstructural changes and mechanical properties. Optimum properties are obtained at intermediate austempering periods (120-240 mm) when both the amount of retained austenite and austenite carbon content are maximum. (author)

  2. Investigations on the fracture toughness of austempered ductile irons austenitized at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P. Prasad; Putatunda, Susil K

    2003-05-25

    Ductile cast iron was austenitized at four different temperatures and subsequently austempered at six different temperatures. Plane strain fracture toughness was evaluated under all the heat treatment conditions and correlated with the microstructural features such as the austenite content and the carbon content of the austenite. Fracture mechanism was studied by scanning electron microscopy. It was found that the optimum austempering temperature for maximum fracture toughness decreased with increasing austenitizing temperature. This could be interpreted in terms of the microstructural features. A study of the fracture mechanism revealed that good fracture toughness is unlikely to be obtained when austempering temperature is less than half of the austenitizing temperature on the absolute scale.

  3. Microstructure and mechanical properties of CuNiMo austempered ductile iron

    OpenAIRE

    Erić Olivera; Jovanović Marina P.; Šiđanin Leposava P.; Rajnović Dragan M.

    2004-01-01

    Microstructure and mechanical properties of Cu, Ni and Mo alloyed cast ductile iron have been investigated after austempering. Samples were austenitised at 860oC for 1h and then austempered at 320oC and 400oC in the interval from 0,5 to 5h. The X-ray diffraction technique and the light microscopy were utilized to investigate the bainitic transformation, while tensile and impact tests were performed for characterization of mechanical properties. By austempering at 320oC in the range between 2 ...

  4. New Possibilities of Shaping the Surface Properties in Austempered Ductile Iron Castings

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2013-01-01

    Full Text Available The paper presents recent developments concerning the formation of surface layer in austempered ductile iron castings. It was found thatthe traditional methods used to change the properties of the surface layer, i.e. the effect of protective atmosphere during austenitising or shot peening, are not fully satisfactory to meet the demands of commercial applications. Therefore, new ways to shape the surface layer and the surface properties of austempered ductile iron castings are searched for, to mention only detonation spraying, carbonitriding, CVD methods, etc.

  5. Microstructure and mechanical properties of CuNiMo austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Erić Olivera

    2004-01-01

    Full Text Available Microstructure and mechanical properties of Cu, Ni and Mo alloyed cast ductile iron have been investigated after austempering. Samples were austenitised at 860oC for 1h and then austempered at 320oC and 400oC in the interval from 0,5 to 5h. The X-ray diffraction technique and the light microscopy were utilized to investigate the bainitic transformation, while tensile and impact tests were performed for characterization of mechanical properties. By austempering at 320oC in the range between 2 and 5h, a microstructure typical for austempered ductile iron was produced, i.e. a mixture of free bainitic ferrite and highly carbon enriched retained austenite. The characteristic of the whole range of austempering at 400oC is the appearance of martensitic structure. The maximum impact energy (133 J coincides with the maximum value of volume fraction of retained austenite that was obtained after 2,5h of austempering at 320oC. The appearance of martensite during austempering at 400oC is the main cause for much lower tensile properties than at 320oC.

  6. Influence of cooling conditions and amount of retained austenite on the fracture of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    VYACHESLAV GORYANY

    2008-01-01

    Full Text Available SEM Analysis of fracture surfaces from tensile test specimens of thick-walled, austempered ductile irons (diameter 160 mm shows different fracture behavior depending on the austenite retained in the matrix. The results show ductile fractures only in areas containing retained austenite sections. In section areas without or with a very low content of retained austenite, only brittle fracture without any plastic deformation occurs. The content of retained austenite determines the amount of ductile fracture in the microstructure.

  7. Effects of Copper and Austempering on Corrosion Behavior of Ductile Iron in 3.5 Pct Sodium Chloride

    Science.gov (United States)

    Hsu, Cheng-Hsun; Lin, Kuan-Ting

    2013-10-01

    Although alloying and heat treatments are common industrial practices to obtain ductile irons with desired mechanical properties, related information on how the two practices affect corrosion behavior is scarce. In this study, two ductile irons—with and without 1 wt pct copper addition—were austempered to obtain austempered ductile irons (ADIs). Polarization tests and salt spray tests were conducted to explore how both copper-alloying and austempering heat treatments influenced the corrosion behavior of ductile irons. The results showed that the corrosion resistance of 1 wt pct copper-alloyed ductile iron was better than that of the unalloyed one, while ADI had improved corrosion resistance compared with the as-cast. In particular, the ductile iron combined with the copper-alloying and austempering treatments increased the corrosion inhibition efficiency up to 84 pct as tested in 3.5 wt pct NaCl solution.

  8. Mechanical properties of a low alloyed austempered ductile iron in the upper ausferrite region

    Energy Technology Data Exchange (ETDEWEB)

    Wen, D.C.

    1999-05-01

    Microstructural observations, X-ray diffraction testing and measurements of mechanical properties were used to study the characteristics of austempering and the influence of tempered martensite on mechanical properties as a function of austempering time at 400 degree C after austenitising at 900 degree C for a 0.77%Cu-0.5%Ni ductile iron. The austempering times were derived from a resistivity curve measured by a vacuum heat treatment system. The experimental results show that the resistivity change curve could be used effectively for selecting the isothermal holding times of austempering treatment, with all The mechanical properties of ADI austempering at times corresponding to the processing window defined by the electrical resistance measurement satisfying the standard requirement. The formation of martensite in austempering reduced the mechanical properties of ADI but these properties could be increased by a treatment tempering at 200 degree C after cooling and to obtain more ductility and toughness as compared with that undergoing single heat treatment. This increase also extended the effective austempering time interval of ADI over which the ASTM standards were satisfied. (author)

  9. The effect of alloy elements on the microstructure and properties of austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Lin, B.Y.; Chen, E.T.; Lei, T.S. [National Taiwan Institute of Technology, Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering

    1995-05-01

    Ductile cast iron has already demonstrated excellent mechanical properties. If given proper austempering, it can exhibit even more outstanding characteristics. The process of austempering for ductile cast iron is similar to steel, and requires an adequate completely, and then rapidly quenching the austenitizing temperature allowing the matrix of ductile iron to be austenitized completely, and then rapidly quenching the austenitized ductile iron down to 300 C--400 C. Caution is required to prevent austenite from transforming into proeutectoid ferrite or pearlite. Finally, the ductile iron must be kept in an isothermal condition for a proper length of time. Many kinds of experimental techniques such as quantitative metallography, magnetic change, dilatometry, X-ray diffraction, electrical resistivity change etc., may be used to measure the phase transformation during the austempering of ductile irons. However, the method of measuring the change of electrical resistivity, not only provides continuous and complete data, but also the time to start and to finish for both stages of the reaction can be significantly determined. In this paper, the effect of alloy elements on the microstructure and property of ADI was investigated. First, the specimens containing Mn, Cu, Ni and Mo were made separately, then a PC-controlled vacuum heat treating system was used for the heat treatments.

  10. Influence of austempering heat treatment on mechanical and corrosion properties of ductile iron samples

    Directory of Open Access Journals (Sweden)

    M. Janjić

    2016-07-01

    Full Text Available Mechanical properties and corrosion resistance of metals are closely related to the microstructure characteristics of the material. The paper compares the results of these two sets of properties after investigating samples of base ductile iron and heat-treated samples of the base austempered ductile iron (ADI. The basic material is perlite ferritic iron alloyed with copper and nickel. To test the corrosion rate of the base material (ductile iron and the heattreated samples (ADI, electrochemical techniques of potentiostatic polarization were used (the technique of Tafel curves extrapolation and the potentiodynamic polarization technique.

  11. Austempering transformation kinetics of austempered ductile iron obtained by Mössbauer Spectroscopy

    Directory of Open Access Journals (Sweden)

    F. Binczyk

    2008-10-01

    Full Text Available The composition of metallic matrix in ductile iron as-cast and after austempering at temperatures of 280, 330 and 380oC (ADI wasexamined. The study presents the results of these examinations obtained by Mössbauer spectroscopy. The specimens were taken from castrods of 60mm diameter. Using calculated values of the parameters of hyperfine interactions (isomeric shift IS, quadrupole splitting QS andhyperfine effective magnetic field H, isolated by deconvolution of the experimental spectrum, the constituents of the metallic matrix were identified in terms of both quantity and quality. The measured values as well as the data compiled in literature indicate that component Z1 (the, so called, Zeeman spectrum sextet is related with 57Fe atoms present in the structure of ferrite α1 (I stage of o→α1 + st transformation, component Z2 is typical of ferrite α2 (II stage of st→α2 + carbides transformation, while component Z3 has its origin in 57Fe atoms seated in the structure of carbides (Fe3C, Fe2C or Fe2,4C. On the other hand, by analysis of the parameters of hyperfine interactions describing the non-magnetic components (L and Q it has been proved that they are typical of austenite.

  12. Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper

    Science.gov (United States)

    Dasgupta, Ranjan Kumar; Mondal, Dipak Kumar; Chakrabarti, Ajit Kumar

    2013-03-01

    The influences of relatively high manganese (0.45 through 1.0 wt pct) and copper (0.56 through 1.13 wt pct) contents on microstructure development and phase transformation in three austempered ductile irons have been studied. The experimental ductile irons alloyed with copper and manganese are found to be practically free from intercellular manganese segregation. This suggests that the positive segregation of manganese is largely neutralized by the negative segregation of copper when these alloying elements are added in appropriate proportions. The drop in unreacted austenite volume (UAV) with increasing austempering temperature and time is quite significant in irons alloyed with copper and manganese. The ausferrite morphology also undergoes a transition from lenticular to feathery appearance of increasing coarseness with the increasing austempering temperature and time. SEM micrographs of the austempered samples from the base alloy containing manganese only, as well as copper plus manganese-alloyed irons, clearly reveal the presence of some martensite along with retained austenite and ferrite. X-ray diffraction analysis also confirms the presence of these phases. SEM examination further reveals the presence of twinned martensite in the copper plus manganese-alloyed samples. The possibility of strain-induced transformation of austenite to martensite during austempering heat treatment is suggested.

  13. Effect of shot peening process on fatigue behavior of an alloyed austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Amir Sadighzadeh Benam

    2011-08-01

    Full Text Available Shot peening is one of the most common surface treatments to improve the fatigue behavior of metallic parts. In this study the effect of shot peening process on the fatigue behavior of an alloyed austempered ductile iron (ADI has been studied. Austempering heat treatment consisted of austenitizing at 875℃ for 90 min followed by austempering at three different temperatures of 320, 365 and 400℃. Rotating-bending fatigue test was carried out on samples after shot peening by 0.4 – 0.6 mm shots. XRD and SEM analysis, micro hardness and roughness tests were carried out to study the fatigue behavior of the samples. Results indicate that the fatigue strengths of samples austempered at 320, 365 and 400℃ are increased by 27.3%, 33.3% and 48.4%, respectively, after shot peening process.

  14. Effect of Water on Ductility and Fatigue Strength of Austempered Ductile Cast Iron (adi)

    Science.gov (United States)

    Yakushiji, Terutoshi; Ferguson, W. George; Goto, Masahiro

    In order to study the mechanism of decreasing tensile strength and elongation of Austempered Ductile Cast Iron (ADI) in the wet condition, various tension tests and impact tests were carried out. Three point bending fatigue tests were carried out on ADI and annealed 0.55% carbon steel to clarify the influence of water on fatigue strength. The main conclusions are as follow. Embrittlement by water begins when plastic deformation starts in a tension test. The fatigue limit of ADI in water showed a lower value than that in air. The influence of a water environment on fatigue behaviour was similar to that of annealed 0.55% carbon steel. Embrittlement such as that in a tension test was not observed in a fatigue test.

  15. Impact toughness and fracture toughness of austempered ductile iron

    OpenAIRE

    Liu, Jingcheng; Guoxiong SUN

    2004-01-01

    The impact toughness and fracture toughness ofaustermpered ductile iron (ADI) are described. The notched and un-notched charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of mormal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at -40 ℃ it still maintains about 70% of the value at room temperature. The properties of...

  16. The Nature of the Tensile Fracture in Austempered Ductile Iron with Dual Matrix Microstructure

    Science.gov (United States)

    Kilicli, Volkan; Erdogan, Mehmet

    2010-02-01

    The tensile fracture characteristics of austempered ductile irons with dual matrix structures and different ausferrite volume fractions have been studied for an unalloyed ductile cast iron containing (in wt.%) 3.50 C, 2.63 Si, 0.318 Mn, and 0.047 Mg. Specimens were intercritically austenitized (partially austenitized) in two phase region (α + γ) at various temperatures for 20 min and then quenched into a salt bath held at austempering temperature of 365 °C for various times and then air cooled to room temperature to obtain various ausferrite volume fractions. Conventionally austempered specimens with fully ausferritic matrix and unalloyed as-cast specimens having fully ferritic structures were also tested for comparison. In dual matrix structures, results showed that the volume fraction of proeutectoid ferrite, new (epitaxial) ferrite, and ausferrite [bainitic ferrite + high-carbon austenite (stabilized or transformed austenite)] can be controlled to influence the strength and ductility. Generally, microvoids nucleation is initiated at the interface between the graphite nodules and the surrounding ferritic structure and at the grain boundary junctions in the fully ferritic microstructure. Debonding of the graphite nodules from the surrounding matrix structure was evident. The continuity of the ausferritic structure along the intercellular boundaries plays an important role in determining the fracture behavior of austempered ductile iron with different ausferrite volume fractions. The different fracture mechanisms correspond to the different levels of ausferrite volume fractions. With increasing continuity of the ausferritic structure, fracture pattern changed from ductile to moderate ductile nature. On the other hand, in the conventionally austempered samples with a fully ausferritic structure, the fracture mode was a mixture of quasi-cleavage and a dimple pattern. Microvoid coalescence was the dominant form of fracture in all structures.

  17. The abrasion and impact-abrasion behavior of austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Dogan, Omer N.; Lerner, Y.S. (University of Northern Iowa)

    1998-01-01

    Austempering of ductile irons has led to a new class of irons, Austempered Ductile Irons (ADIs), with improved mechanical strength and fracture toughness lacking in gray cast irons. Laboratory wear tests have been used to evaluate the abrasive and impact-abrasive wear behavior of a suite of ADIs. The use of high-stress, two-body abrasion, low-stress, three-body abrasion, and impact-abrasion tests provides a clear picture of the abrasive wear behavior of the ADIs and the mechanisms of material removal. When combined with hardness measurements, fracture toughness and a knowledge of the microstructure of the ADIs, the overall performance can be assessed relative to more wear resistant materials such as martensitic steels and high-chromium white cast irons

  18. Study of mechanical, physical, and corrosion behavior of 0.5% cobalt alloyed austempered ductile iron

    Science.gov (United States)

    Abdullah, Bulan; Jaffar, Ahmed; Alias, Siti Khadijah; Ramli, Abdullah; Izham, Mohd Faizul

    2010-03-01

    Objectives: The purpose of this research was to determine the mechanical properties and corrosion behavior of 0.5% Co-DI before and after heat treatment and compare with commercial ductile iron. Methods: Molten metal of newly developed ductile iron which alloyed with 0.5% Cobalt produced through CO2 sand casting method. The specimens then performed preheat to 500°C in an hour then oil quenched. Specimens then performed annealing to 900°C in half an hour before oil quenched again. 500°C, 600°C and 700°C austempering temperature had been selected subjected to the specimens in half an hour before cooled to room temperature. The tests involved are microstructure analysis which included nodule count and phase analysis, polarization test, spectrometer test, density test, tensile test (ASTM E 8M), hardness test and impact test (ASTM A327) on as cast and austempered specimen. Results: 0.5% Cobalt alloyed austempered ductile iron with 500°C austempered temperature is the optimum temperature for 0.5% Co-ADI. It's not only increase the nodule count in the content, but also improve the mechanical properties such as impact toughness and tensile strength. Corrosion rate of 0.5% Co-DI also improved compare to unalloyed DI.

  19. Wear behavior of an austempered ductile iron containing Mo-Ni-Cu

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, S.; Rahimi, M.A. [Faculty of Materials Engineering, Sahand Univ. of Technology, Tabriz (Iran)

    2005-07-01

    The aim of the this investigation is to study the influence of Ni on tribiological behavior of an austempered ductile iron (ADI) containing Mo, Ni and Cu. Ductile irons with chemical composition Fe-3.56%C-2.67%Si -0.25%Mo-0.5%Cu and Ni contents of 0.8 and 1.5% were cast into standard Y-blocks. Wear test samples were machined off from the bottom section of blocks. Austenitizing heat treatment was carried out at 870 C temperature followed by austempering at 270, 320, and 370 C for 5-1140 minutes. The wear test was carried out by using block-on-ring test machine. Sliding dry wear behavior was studied under applied loads of 50, 100 and 150 N. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Wear mechanism is described as being due to subsurface fatigue, with cracks nucleated at plastically, deformed graphite interfaces. The wear controlling mechanism is the crack growth when wear shows a dependence on applied load and austempering temperature. (orig.)

  20. Impact toughness and fracture toughness of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Jingcheng LIU

    2004-11-01

    Full Text Available The impact toughness and fracture toughness ofaustermpered ductile iron (ADI are described. The notched and un-notched charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of mormal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at -40 ℃ it still maintains about 70% of the value at room temperature. The properties of fracture toughness are important in safety design and failure analysis. In this study all fracture toughness data of ADI are higher than that of conventional ductile iron, and are equivalent to or better than that of steel castings o forged steel pieces with the tensile strength equivalent to ADI.

  1. Microstructural investigation of austempered ductile irons with ultrasonic method; Ultraschall-Gefuegeuntersuchungen von zwischenstufenverguetetem Sphaeroguss

    Energy Technology Data Exchange (ETDEWEB)

    Topuz, A. [Yildiz Technical Univ., Istanbul (Turkey). Metallurgical Engineering Dept.; Topcu, E. [Yildiz Technical Univ., Istanbul (Turkey). Metallurgical Engineering Dept.; Bakkaloglu, A. [Yildiz Technical Univ., Istanbul (Turkey). Metallurgical Engineering Dept.; Marsoglu, M. [Yildiz Technical Univ., Istanbul (Turkey). Metallurgical Engineering Dept.

    1997-06-01

    In this study, the relationship between the matrix structure and the sonic velocity of ductile iron in the as-cast and austempered heat treatment conditions was investigated. The sonic velocity in 12 different ductile irons (unalloyed, alloyed with Ni, Mo, Cu, Ni+Cu and Ni+Mo+Cu) has been measured in the as-cast condition and austempered conditions. The investigations have shown that cast iron that should meet the minimum specification of 90% nodularity requires the minimum velocity of 5680 m/s in the as-cast condition and 5450 m/s in the at 235 C austempered condition. From experimental data the equation CT{sup a}=B has been found for austempered conditions. (orig.) [Deutsch] In der vorliegenden Arbeit wurde der Zusammenhang zwischen dem Matrixgefuege und der Schallgeschwindigkeit von Sphaeroguss im Guss- und Zwischenstufenverguetungszustand untersucht. Die Schallgeschwindigkeit wurde in 12 verschiedenen Proben aus Sphaeroguss (unlegiert, legiert mit Ni, Mo, Cu, Ni+Cu und Ni+Mo+Cu) im gegossenen und vergueteten Zustand gemessen. Die Untersuchungen ergaben, dass Gusseisen mit einem Grad der Sphaerolitbildung von mindestens 90% die geringste Schallgeschwindigkeit von 5680 m/s im Gusszustand und 5450 m/s im zwischenstufenvergueteten Zustand erreichte. Aus den experimentellen Ergebnissen wurde die Formel CT{sup a}=B fuer den zwischenstufenvergueteten Zustand errechnet. (orig.)

  2. Investigations on the fracture toughness of austempered ductile iron alloyed with chromium

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P. Prasad; Putatunda, Susil K

    2003-04-15

    An investigation was carried out to examine the influence of chromium content on the plane strain fracture toughness of austempered ductile iron (ADI). ADIs containing 0, 0.3 and 0.5 wt.% chromium were austempered over a range of temperatures to produce different microstructures. The microstructures were characterized by optical microscopy and X-ray diffraction. Plane strain fracture toughness of all these materials was determined and correlated with microstructure and chromium content. The chromium content was found to influence the fracture toughness through its influence on the processing window. Since the chromium addition shifts the processing window to shorter durations, the higher chromium alloys at higher austempering temperatures tend to fall outside of the processing window, resulting in less than optimum microstructure and inferior fracture toughness. A small chromium addition of 0.3 wt.% was found to be beneficial for the fracture toughness of ADI.

  3. Statistical Assessment of the Impact of Elevated Contents of Cu and Ni on the Properties of Austempered Ductile Iron

    Directory of Open Access Journals (Sweden)

    Nawrocki P.

    2016-12-01

    Full Text Available The article presents a statistical analysis of data collected from the observation of the production of austempered ductile iron. The impact assessment of the chemical composition, i.e. high contents of Cu and Ni on the properties of ductile iron isothermal tempered is critical to find the right chemical composition of austempered ductile iron. Based on the analyses range of the percentage of Cu and Ni which were selected in the cast iron to obtain material with high strength properties.

  4. 350℃ - Thermal Stability of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    M. Pellizzari; M. Zadra, A. Molinari

    2004-01-01

    The thermal stability of an ADI has been studied by isothermal aging at 350℃ for 150 hours, measuring the amount of retained austenite and its carbon content by X-ray diffractometry. The influence of different austempering treatments, carried out at temperatures between 300 and 450℃ (300, 330, 360, 410 and 450℃) and holding times between15 and 60 minutes (15, 30, 45, 60), was considered. Thermal stability depends on whether austempering temperature is higher or lower than the ageing one. Thermal stability increases by increasing austempering temperatures, from 300° to410℃. Samples treated at 410° and 450° show a lower austenite decomposition than samples at 300-330-360℃. A drop in stability is shown by increasing the austempering temperature from 410° to 450℃. The results have been interpreted on the basis of the austenite stability out of the processing window, which in turn depends on the austempering parameters.

  5. Thermal Stability of Austempered Ductile Iron Evaluated in a Temperature Range of 20-300K

    Directory of Open Access Journals (Sweden)

    Dawid MYSZKA

    2016-05-01

    Full Text Available The aim of this article was to determine through changes in magnetic properties the stability of the austempered ductile iron (ADI microstructure during temperature changes in a range of 20 – 300 K. The measurements were taken in a vibrating sample magnetometer (VSM using Fe27Ni2TiMoAlNb austenitic stainless steel and four types of austempered ductile iron obtained under various heat treatment conditions. The plotted curves showing changes in the magnetisation degree as a function of temperature had a number of characteristic points illustrating changes taking place in the microstructure. For each of the materials examined, the martensite start temperature Ms and the temperature range within which the martensitic transformation takes place were identified.

  6. Fatigue crack propagation characteristics of ductile cast iron austempered from (. alpha. +. gamma. ) phase region. (. alpha. +. gamma. ) iki kara austemper shorishita kyujo kokuen chutetsu no hiro kiretsu shinten tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Y.; Asami, K.; Kuroiwa, H. (Musashi Institute of Technoloyg, Tokyo (Japan))

    1991-01-15

    In order to enhance the fatigue crack propagation resistance of ductile cast iron, the effect of austempering from a ({alpha} + {gamma}) phase region was studied. As the dual phase matrix microstructure of ferrite and pearlite in as-casted iron was changed into the dual phase one of ferrite and bainite by partial austempering from 800 {degree} C, the fatigue crack propagation resistance was enhanced over the whole range of a {Delta} K region. The enhancement of the fatigue crack propagation resistance was caused by remarkable development of crack closures from higher {Delta} K regions which was induced by fracture contact and fretting because of an increase in fracture roughness and easy formation of oxide deposits. In addition, the static tensile and ductility of ductile cast iron were possibly enhanced simultaneously by partial austempering for changing pearlite into bainite superior in both tensile and ductility. 9 refs., 13 figs., 3 tabs.

  7. Rolling contact fatigue strength of successive austempered ductile cast iron; Chikuji austemper shori kyujo kokuen chutetsu no korogari hiro kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, T. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering; Ogi, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Sawamoto, A. [Yamaguchi Univ., Yamaguchi (Japan). Faculty of Education

    1998-04-25

    The holding time of austempered spheroidal graphite cast iron material is allowed to vary in heat treatment especially at the lower bainite transformation zone during the process for the preparation of specimens different from each other in the amount of {gamma}-pool, and the specimens are tested for their rolling contact fatigue strength. The effects of the amount of {gamma}-pool, roughness of the bainite structure, and work-hardening, on the rolling fatigue strength are also studied. Findings obtained as the result of experiment are stated below. In the case of an austempered ductile cast iron specimen containing a {gamma}-pool amount that occupies a high rate of 6.52%, the rolling fatigue withstanding limit exhibits a relatively high level of 1310MPa, which becomes approximately 1245MPa when the holding time is extended in the lower bainite transformation zone. The limit rises to approximately 1320MPa at a stage where the {gamma}-pool virtually disappears. In a successive austempering treatment process that aims at improving on machinability and at allowing sufficient fatigue strength to be maintained, it is necessary to allow the holding time in the bainite zone to be long enough for the {gamma}-pool to disappear and for the lower bainite structure to grow sufficiently. 5 refs., 10 figs., 4 tabs.

  8. Effect of Copper and Nickel on the Transformation Kinetics of Austempered Ductile Iron

    Science.gov (United States)

    Górny, Marcin; Tyrała, Edward; Lopez, Hugo

    2014-10-01

    The kinetics of reaction occurring during the austempering treatment of ductile iron (DI) containing different additions of Cu and Ni was investigated in this work. DI bars were heat treated in an instrumented dilatometer in order to follow the exhibited transformation kinetics. The dilatometric results indicated that the addition of Cu alone did not have a significant effect on the incubation times for the austempering transformation. Also, the addition of both, Cu and Ni resulted in a significant effect on reducing the transformation rates. It was found that the austempering process is characterized by two clearly distinguished transformation stages. In the initial stage, the addition of Cu, and to a greater extent, additions of both Cu and Ni led to reductions in the transformation rates shifting the maximum transformation rate values toward longer times. The outcome of this work indicates that during the first stage of austempering, nucleation of the ferrite plates occurs via a diffusionless mechanism while their growth is diffusion controlled. Moreover, after the maximum in the transformation rate has been reached, the growth of ferrite plates becomes dominant with the rate-limiting step becoming the diffusion of C into the surrounding austenite. A qualitative model for the austempering transformation is proposed in this work to account for the experimental observations.

  9. In-situ measurement of phase transformation kinetics in austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Leopold, E-mail: leopold.meier@utg.de [Technische Universität München, Lehrstuhl für Umformtechnik und Gießereiwesen, Walther-Meißner-Straße 4, 85748 Garching (Germany); Hofmann, Michael, E-mail: michael.hofmann@frm2.tum.de [Technische Universität München, Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Lichtenbergstraße 1, 85748 Garching (Germany); Saal, Patrick, E-mail: patrick.saal@utg.de [Technische Universität München, Lehrstuhl für Umformtechnik und Gießereiwesen, Walther-Meißner-Straße 4, 85748 Garching (Germany); Volk, Wolfram, E-mail: wolfram.volk@utg.de [Technische Universität München, Lehrstuhl für Umformtechnik und Gießereiwesen, Walther-Meißner-Straße 4, 85748 Garching (Germany); Hoffmann, Hartmut, E-mail: hartmut.hoffmann@utg.de [Technische Universität München, Lehrstuhl für Umformtechnik und Gießereiwesen, Walther-Meißner-Straße 4, 85748 Garching (Germany)

    2013-11-15

    Austempered ductile iron (ADI) alloyed with 0.42% Mn and 0.72% Cu was heat treated in a mirror furnace and the phase transitions were studied in-situ by neutron diffraction. The heat treatment consisted of austenitisation at 920 °C and isothermal austempering at 400 °C, 350 °C and 300 °C, respectively. Due to the growth of ferrite platelets, the austenite content decreases rapidly at all temperatures within the first 15–20 min and reaches a stable plateau after 35 min (400 °C) to 80 min (300 °C). The carbon content of the residual austenite, which was monitored and characterised by the change of the lattice parameter, increases up to 1.6 wt.% caused by redistribution from the newly formed ferrite. While at higher austempering temperatures this takes place almost parallel to the phase transformation, at 300 °C the redistribution of carbon to austenite lags behind considerably. Furthermore the neutron data revealed an austenite peak asymmetry during austempering which is attributed to successive phase transformation. It results temporarily in two fractions of austenite, an initial low-carbon and an enriched high-carbon modification. - Highlights: • The heat treatment of ADI was studied in detail by in-situ neutron diffraction. • The phase fractions were monitored and evaluated quantitatively. • The austenite carbon content increased up to 1.6 wt.% during austempering. • Peak asymmetries indicate two austenite fractions during highest transformation rates.

  10. Influence of Copper Addition and Temperature on the Kinetics of Austempering in Ductile Iron

    Science.gov (United States)

    Amran, Yogev; Katsman, Alexander; Schaaf, Peter; Bamberger, Menachem

    2010-10-01

    Austempered ductile iron (ADI) is a material that exhibits excellent mechanical properties because of its special microstructure, combining ferrite and austenite supersaturated with carbon. Two ADI alloys, Fe-3.5 pct C-2.5 pct Si and Fe-3.6 pct C-2.7 pct Si-0.7 pct Cu, austempered for various times at 623 K (350 °C) and 673 K (400 °C) followed by water quenching, were investigated. The first ferrite needles nucleate mainly at the graphite/austenite interface. The austenite and ferrite weight fractions increase with the austempering time until stabilization is reached. The increase in the lattice parameter of the austenite during austempering corresponds to an increase of carbon content in the austenite. The increase in the ferrite weight fraction is associated with a decrease in microhardness. As the austempering temperature increases, the ferrite weight fraction decreases, the high carbon austenite weight fraction increases, but the carbon content in the latter decreases. Copper addition increases the high carbon austenite weight fraction. The results are discussed based on the phases composing the Fe-2Si-C system.

  11. Development of high toughness in austempered type ductile cast iron and evaluation of its properties

    Science.gov (United States)

    Kobayashi, Toshiro; Yamamoto, Hironobu

    1988-02-01

    In order to increase the toughness of austempered ductile cast irons, we attempted to strengthen the fracture initiation sites such as graphite-matrix interfaces and eutectic cell boundaries in a way of the microsegregation of alloying elements. For instance, the retained austenite which is stable under external stresses may be introduced preferentially into these sites by the addition of Ni, which segregates to a graphite periphery and of Mn, which partitions mainly to eutectic cell boundaries. Following this concept, the effects of various austempering processes on toughness are also in-vestigated. The cast iron alloying with Ni and Mn shows the best fracture toughness when it is heat-treated by either QB' or B' process; here, the QB' means the oil-quenching from an austenite γ phase range followed by austempering from a ferrite α plus γ range and the B' means austempering from a (α + γ) range. In the newly developed iron, there is a mixed microstructure composed of the ferrite, bainitic ferrite, and austenite. Abnormal elongation due to the TRIP effect in the austenite phase is found to have occurred at about 198 K. Moreover, it is shown that this TRIP effect may be caused by the formation of deformation twins.

  12. Effect of Cu, Mo, Si on the content of retained austenite of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Y. [Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering

    1995-05-01

    In this paper, the effects of Cu, Mo, Si contents on the volume fraction of retained austenite of austempered ductile iron (ADI) are analyzed exactly by X-ray diffraction, and the fracture modes of test samples with different volume fraction of retained austenite are investigated by SEM. It is shown that the retained austenite content increases with the content of copper, decreases with the content of molybdenum, and reaches the maximum with a certain content of silicon. When the retained austenite content decreases, the fracture modes of test samples change from ductile fracture to cleavage fracture.

  13. The bainite reaction kinetics in austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Taran, Yu.N.; Uzlov, K.I.; Kutsov, A.Yu. [State Metall. Acad., Dnepropetrovsk (Ukraine). Phys. Metall. Dept.

    1997-11-01

    Bainitic reaction kinetics in ductile iron contained according to Ukrainian standard (weight%) 3.60-3.80 carbon, 2.60-2.80 Si, {proportional_to}0.12 Mn, {proportional_to}0.60 Cu and additionally alloyed by Mo (0.15-0.20) has been studied. It was found that the overall transformation kinetics becomes slower as transformation temperature increase. This is because more intensive redistribution of carbon into austenite at higher temperatures. Two austenites with different carbon content have been fixed and kinetics of their lattices parameters has been studied. (orig.). 6 refs.

  14. Ameliorated Austenite Carbon Content Control in Austempered Ductile Irons by Support Vector Regression

    Directory of Open Access Journals (Sweden)

    Chan-Yun Yang

    2013-01-01

    Full Text Available Austempered ductile iron has emerged as a notable material in several engineering fields, including marine applications. The initial austenite carbon content after austenization transform but before austempering process for generating bainite matrix proved critical in controlling the resulted microstructure and thus mechanical properties. In this paper, support vector regression is employed in order to establish a relationship between the initial carbon concentration in the austenite with austenization temperature and alloy contents, thereby exercising improved control in the mechanical properties of the austempered ductile irons. Particularly, the paper emphasizes a methodology tailored to deal with a limited amount of available data with intrinsically contracted and skewed distribution. The collected information from a variety of data sources presents another challenge of highly uncertain variance. The authors present a hybrid model consisting of a procedure of a histogram equalizer and a procedure of a support-vector-machine (SVM- based regression to gain a more robust relationship to respond to the challenges. The results show greatly improved accuracy of the proposed model in comparison to two former established methodologies. The sum squared error of the present model is less than one fifth of that of the two previous models.

  15. Behavior Of Austempered Ductile Irons (ADI) Subjected To Laser Surface Melting

    Science.gov (United States)

    Jones, D. L.; Fagoaga, I.; Liceaga, J. F.; Sanz Justes, Pedro; Jasnowski, Kazie S.

    1989-03-01

    The near surface microstructure of 3 austempered ductile irons has been modified using laser surface melting (LSM). A white cast iron layer was produced to depths of up to 500 microns. The microstructure of this region varied depending upon the parameters used. A heat affected zone (HAZ) appeared at an abrupt transition between the LSM zone and the substrate. The size of the HAZ, which varied between 20 and 200 microns was predominately affected by the pass velocity in the range of energies used. The hardness profiles showed large variations in the Haz probably due to varing tempering effects from the subsequent passes.

  16. Effect of heat treatment on the thermal expansion coefficient of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Tadayon saidi, M. [Dept. Metallurgy-Karaj Azad Univ.-Karaj (Iran); Baghersaie, N. [Tehran Center, Control Dept., Eng. Research Inst., Ministry of Jihad Agriculture (Iran); Varahram, N. [RAZI Metallurgical Research Inst.-Tehran (Iran)

    2005-07-01

    Austempered ductile iron provide a unique combination of strength and toughness coupled with excellent design flexibility for automotive application as compared to forged or cast steels. Some material properties such as thermal expansion coefficient and its influence in final machining tolerance is a matter of discussion in the automotive industry. In this study the effect of heart treatment cycle on the microstructure and thermal expansion of ADI was investigated. Samples were austempered at 275 C and 375 C for one hour and then dilatometric test carried out in the temperature range of 50 C to 350 C, then the result was compared with the thermal expansion coefficient of forged steel. Microstructure and mechanical investigations were used to the assurance of these results. The results indicate that replacing of forged steel with ADI due to lower cost production and reduction in weight is possible if the correct tolerance were selected. (orig.)

  17. Mechanical Property Stability of Cu-Mo-Ni Alloyed Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    LIU Sheng-fa; WANG Zhong-fan

    2005-01-01

    The aim of present work is to investigate the influencing factors on mechanical property stability of Cu-Mo-Ni alloyed austempered ductile iron (ADI). The results show that after austenitized at 900 ℃ for 2 h followed by austempered at 370 ℃ for another 2 h, the mechanical property of the alloyed ADI can reach the Germanite GGG-100 standard, i.e.σb≮1 000 MPa, δ≮5%, at 95% confidence level. And the satisfactory mechanical properties were obtained when the alloyed ADI was austenitized at 850 ℃ to 1 000 ℃ for 1-4 h, and austempered at 355 ℃ to 400 ℃ for another 1 h to 4 h. The microstructures, including nodule number, white bright zone content (martensite-containing interdendritic segregation zone) and retained austenite content, can significantly influence the mechanical properties of the ADI. In order to obtain the good combinations of strength and ductility, the volume fraction of white bright zone should be less than 5%, and the retained austenite contents maintain between 30 % and 40 %. The application of inoculation techniques to increase graphite nodule number can effectively reduce the white bright zone content in the structure.

  18. Transition temperature and fracture mode of as-castand austempered ductile iron.

    Science.gov (United States)

    Rajnovic, D; Eric, O; Sidjanin, L

    2008-12-01

    The ductile to brittle transition temperature is a very important criterion that is used for selection of materials in some applications, especially in low-temperature conditions. For that reason, in this paper transition temperature of as-cast and austempered copper and copper-nickel alloyed ductile iron (DI) in the temperature interval from -196 to +150 degrees C have been investigated. The microstructures of DIs and ADIs were examined by light microscope, whereas the fractured surfaces were observed by scanning electron microscope. The ADI materials have higher impact energies compared with DIs in an as-cast condition. In addition, the transition curves for ADIs are shifted towards lower temperatures. The fracture mode of Dls is influenced by a dominantly pearlitic matrix, exhibiting mostly brittle fracture through all temperatures of testing. By contrast, with decrease of temperature, the fracture mode for ADI materials changes gradually from fully ductile to fully brittle.

  19. Morphology and constitution of the phases in as-welded microstructure of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.Y.; Zhou, Z.F.; Sun, D.Q.

    2005-06-15

    It was found by optical and electron microscopic examination of the microstructure of as-weld austempered ductile iron that the weld matrix is composed of austenite and bainite, the volume fractions of which were determined. In addition, the carbon content of austenite was measured and therefore the average carbon content of the matrix was calculated. In the matrix of the weld metal two types of bainite, bainite ferrite and lower bainite, were found. According to the morphology and distribution of the bainite plates, the nucleation and growth modes of bainite was inferred. (author)

  20. Effects of matrix structures on fracture mechanisms of austempered ductile cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Shigeru; Matsufuji, Kenichi [Oita Univ. (Japan); Mitsunaga, Koichi [Kagoshima Junior Womens College (Japan); Takahara, Masao [Isuzu Motors, Kawasaki, Kanagawa (Japan)

    1995-12-31

    On the fatigue behavior of Austempered Ductile Iron (so called ADI), rotating fatigue tests in very high cycle region were performed. The S-N curve represented the double bending. This behavior is caused by the high cycle (>10{sup 7} cycles) fracture, and called the complex three region fractures. The main reason is the work hardening in the surface layer. Therefore, it was removed by electropolishing the surface layer with work hardening. The S-N curve did not show the double bending mentioned above. The fatigue strength with bainitic structure of electropolished ADI was higher than those of mother pearlitic structure.

  1. Mathematical formalisms to represent knowledge concerning the production process of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    D. Wilk-Kołodziejczyk

    2015-10-01

    Full Text Available The aim of this study is to develop computer tools for calculation of the Fe - Fe3C phase equilibrium diagram. The phase equilibrium diagram is of fundamental importance in materials science and heat treatment processes of ferrous alloys. It enables prediction of carbon steel microstructure in the annealed condition, and facilitates selection of proper temperature for the heat treatment process. Choosing the right values of the heat treatment process parameters is essential in the production of Austempered Ductile Iron (ADI.

  2. Effect of austempering parameters on microstructure and mechanical properties of horizontal continuous casting ductile iron dense bars

    Directory of Open Access Journals (Sweden)

    Chun-jie Xu

    2015-03-01

    Full Text Available In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters (i.e. austenitizing temperature and time, and austempering temperature and time on microstructure and mechanical properties of LZQT500-7 ductile iron dense bars with 172 mm in diameter which were produced by horizontal continuous casting (HCC. The results show that the major factors influencing the hardness of austempered ductile iron (ADI are austenitizing temperature and austempering temperature. The fraction of retained austenite increases as the austenitizing and austempering temperatures increase. When austenitizing temperature is low, acicular ferrite and retained austenite can be efficiently obtained by appropriately extending the austenitizing time. The proper austmepering time could ensure enough stability of retained austenite and prevent high carbon austenite decomposition. The optimal mechanical properties of ADI can be achieved with the following process parameters: austenitizing temperature and time are 866 °C and 135 min, and austempering temperature and time are 279 °C and 135 min, respectively. The microstructure of ADI under the optimal austempering process consists of fine acicular ferrite and a small amount of retained austenite, and the hardness, tensile strength, yield strength, elongation and impact toughness of the bars are HBW 476, 1670 MPa, 1428 MPa, 2.93% and 25.7 J, respectively.

  3. Influence of casting size and graphite nodule refinement on fracture toughness of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.C.; Hsu, C.H.; Chang, C.C.; Feng, H.P. [Tatung Inst. of Tech., Raipei (Taiwan, Province of China). Dept. of Materials Engineering

    1998-10-01

    Casting size affects the solidification cooling rate and microstructure of casting materials. Graphite nodules existing in the structure of ductile iron are an inherent and inert second phase that cannot be modified in subsequent heat-treatment processing. The matrix and the fineness of the second phase undoubtedly have some impact on the fracture toughness of the as-cast material, as does the subsequent heat treatment, as it alters the microstructure. This research applied austempering heat treatment to ductile iron of different section sizes and graphite nodule finenesses. The influence of these variables on the plane strain fracture toughness (K{sub IC}) of the castings so treated was compared to that of the as-cast state. Metallography, scanning electron microscopy (SEM), and X-ray diffraction analysis were performed to correlate the properties attained to the microstructural observation.

  4. Effect of Graphite Nodule Diameter on Water Embrittlement of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    CAI Qi-zhou; WEI Bo-kang; TANAKA Yuichi

    2005-01-01

    Effects of graphite nodule diameter on the water embrittlement of austempered ductile iron (ADI) is studied. The water embrittlement mechanism is discussed. Due to water adhesion, local embrittlement occurs on the surface of ADI specimen, resulting in early fracture and significant reduction in tensile strength and elongation. The water embrittlement is the cracking of stress induced martensite formed during tensile deformation caused by hydrogen diffusion decomposed from water and as a result tensile strength and elongation of ADI are remarkably reduced. The segregation of alloying elements in ductile iron is weakened with decreasing nodule diameter, reducing the residual austenite in grain boundaries, then decreasing the amount of stress induced martensite during tensile plastic deformation and finally restraining ADI water embrittlement.

  5. Multi-Response Optimization of Carbidic Austempered Ductile Iron Production Parameters using Taguchi Method

    Science.gov (United States)

    Dhanapal, P.; Mohamed Nazirudeen, S. S.; Chandrasekar, A.

    2012-04-01

    Carbide Austempered Ductile Iron (CADI) is the family of ductile iron containing wear resistance alloy carbides in the ausferrite matrix. This CADI is manufactured by selecting and characterizing the proper material composition through the melting route done. In an effort to arrive the optimal production parameters of multi responses, Taguchi method and Grey relational analysis have been applied. To analyze the effect of production parameters on the mechanical properties signal-to-noise ratio and Grey relational grade have been calculated based on the design of experiments. An analysis of variance was calculated to find the amount of contribution of factors on mechanical properties and their significance. The analytical results of Taguchi method were compared with the experimental values, and it shows that both are identical.

  6. In-Situ Studies of Intercritically Austempered Ductile Iron Using Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Druschitz, Alan [University of Alabama, Birmingham; Aristizabal, Ricardo [University of Alabama, Birmingham; Druschitz, Edward [University of Alabama, Birmingham; Hubbard, Camden R [ORNL; Watkins, Thomas R [ORNL; Walker, Larry R [ORNL; Ostrander, M [Rex Heat Treat, Anniston, AL

    2012-01-01

    Intercritically austempered ductile irons hold promise for applications requiring fatigue durability, excellent castability, low production energy requirements, reduced greenhouse gas emissions and excellent machinability. In the present study, four different ductile iron alloys, containing manganese and nickel as the primary austenite-stabilizing elements, were heat treated to obtain different quantities of austenite in the final microstructure. This paper reports the microstructures and phases present in these alloys. Further, lattice strains and diffraction elastic constants in various crystallographic directions and the transformation characteristics of the austenite as a function of applied stress were determined using in-situ loading with neutron diffraction at the second generation Neutron Residual Stress Facility (NRSF2) at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL).

  7. In Situ Studies of Intercritically Austempered Ductile Iron Using Neutron Diffraction

    Science.gov (United States)

    Druschitz, Alan P.; Aristizabal, Ricardo E.; Druschitz, Edward; Hubbard, C. R.; Watkins, Thomas R.; Walker, L.; Ostrander, Mel

    2012-05-01

    Intercritically austempered ductile irons hold promise for applications requiring fatigue durability, excellent castability, low production energy requirements, reduced greenhouse gas emissions, and excellent machinability. In the present study, four different ductile iron alloys, containing manganese and nickel as the primary austenite-stabilizing elements, were heat treated to obtain different quantities of austenite in the final microstructure. This article reports the microstructures and phases present in these alloys. Furthermore, lattice strains and diffraction elastic constants in various crystallographic directions and the transformation characteristics of the austenite were determined as a function of applied stress using in situ loading during neutron diffraction at the second generation Neutron Residual Stress Facility at the High Flux Isotope Reactor at Oak Ridge National Laboratory.

  8. Un-lubricated sliding wear performance of unalloyed austempered ductile iron under high contact stresses

    Energy Technology Data Exchange (ETDEWEB)

    Zimba, J.; Samandi, M.; Yu, D.; Chandra, T.; Navara, E.; Simbi, D.J

    2004-08-15

    The dry sliding wear behaviour of unalloyed austempered ductile iron (ADI) was studied in a reciprocating tribotester using contact loads in the range 40-140 N. The results obtained show that austempering in the temperature range 325-375 deg. C significantly improves the tribological properties of the unalloyed spheroidal graphite iron. The friction coefficient was reduced by a factor of ten (10) with the wear resistance increasing by several orders of magnitude. The improvement in wear performance was attributed to: the lubricity inherent the graphite nodules, the increase in initial hardness brought about by the ausferrite structure, and the work hardening of the surface as retained austenite is transformed to martensite by plastic deformation, and in the process reducing considerably the sensitivity of the specific wear rate to loading. Optical, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results pertaining to the wear tracks suggest that two main wear mechanisms are responsible for material removal in the unlubricated sliding wear of ADI, namely, plastic yielding and oxidation, with the latter producing hard oxide particles that act as abrasives. Massive plastic yielding followed by delamination and sometimes oxidation accounts for material loss in the much softer as cast ductile spheroidal graphite iron.

  9. Effect of boron on the microstructure and mechanical properties of carbidic austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Peng Yuncheng; Jin Huijin [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu Jinhai, E-mail: pyc_wanhj@163.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Li Guolu [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China)

    2011-11-25

    Highlights: {yields} Boron are applied to carbidic austempered ductile iron (CADI). {yields} Boron microalloying CADI is a new high hardenability of wear-resistant cast iron. {yields} Addition of boron to CADI significantly improves hardenability. {yields} Effect of boron on the CADI grinding ball were investigated. {yields} Optimum property is obtained when boron content at 0.03 wt%. - Abstract: Carbidic austempered ductile iron (CADI) castings provide a unique combination of high hardness and toughness coupled with superior wear resistance properties, but their hardenability restricts their range of applications. The purpose of this study was to investigate the influence of boron on the microstructure and mechanical properties of CADI. The experimental results indicate that the CADI comprises graphite nodules, which are dispersive boron-carbides that are distributed in the form of strips, and the matrix is a typical ausferritic matrix. Microscopic amounts of boron can improve the hardenability of CADI, but higher boron content reduces the hardenability and toughness of CADI. The results are discussed in the context of the influence of boron content on the microstructure and mechanical properties of grinding balls.

  10. FATIGUE PROPERTIES OF AUSTEMPERED DUCTILE IRON (ADI)IN WATER ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    Q.Z.Cai; B.K.Wei; Y.Tanaka

    2004-01-01

    The acicular ferrite in austempered ductile iron(ADI)matrix around graphite was corroded preferentially in wet condition,promoting crack origination and propagation and resulting in the disappearance of ADI fatigue limit.ADI fatigue strength was gradually reduced with increasing the time of test and was reduced by 50% in wet condition at 107 cycles compared with the fatigue limit in dry condition.The fatigue strength variation of ferritic ductile iron in wet condition was similar to that of ADI.The ferritic ductile iron,however,has better corrosion resistance so that the fatigue strength was lowered only by 10% in wet condition at 107 cycles compared with the fatigue limit in dry condition.On the other hand,the fatigue limits of A DI and ferritic ductile iron were dropped by 32% and 25% in tap water dipping 480h/dry condition respectively compared with those in dry condition.The reduction of fatigue limit was attributed to corrosion pits formation correlated with stress concentration,resulting in origination and propagation of fatigue crack.

  11. In Situ Study of the Influence of Nickel on the Phase Transformation Kinetics in Austempered Ductile Iron

    Science.gov (United States)

    Saal, Patrick; Meier, Leopold; Li, Xiaohu; Hofmann, Michael; Hoelzel, Markus; Wagner, Julia N.; Volk, Wolfram

    2016-02-01

    Phase fractions and austenite carbon contents in austempered ductile iron samples with three different nickel contents were determined by in situ neutron diffraction. The samples were austenitized at 1178 K (905 °C) for 30 minutes and austempered for 3.5 hours at temperatures between 523 K and 723 K (250 °C and 450 °C) using a mirror furnace. Based on the in situ neutron diffraction studies, plateau times were derived, which determine the end of stage I reaction. The austenite contents increase for higher austempering temperatures when the austempering times are selected properly, considering the accelerated phase transformation at higher temperature. Appropriate austempering times were derived for austempering temperatures between 523 K and 723 K (250 °C and 450 °C). Increased nickel contents lead to higher austenite phase fractions. Moreover the retarding effect of nickel on the phase transformation was quantified. The plateau values of phase fraction and the according austempering times were converted to TTT diagrams. The evolution of the austenite carbon content shows a maximum at 623 K (350 °C) austempering temperature. This can be explained by temperature-dependent carbide precipitation and carbon diffusion into lattice defects. Fine carbides within the ferrite could be found by preliminary APT analysis.

  12. Improvement in Abrasion Wear Resistance and Microstructural Changes with Deep Cryogenic Treatment of Austempered Ductile Cast Iron (ADI)

    Science.gov (United States)

    Šolić, Sanja; Godec, Matjaž; Schauperl, Zdravko; Donik, Črtomir

    2016-10-01

    The application of a deep cryogenic treatment during the heat-treatment processes for different types of steels has demonstrated a significant influence on their mechanical and tribological properties. A great deal of research was conducted on steels, as well as on other kinds of materials, such as hard metal, gray cast iron, aluminum, aluminum alloys, etc., but not on austempered ductile iron (ADI). In this research the influence of a deep cryogenic treatment on the microstructure and abrasive wear resistance of austempered ductile iron was investigated. The ductile cast iron was austempered at the upper ausferritic temperature, deep cryogenically treated, and afterwards tempered at two different temperatures. The abrasion wear resistance was tested using the standard ASTM G65 method. The microstructure was characterized using optical microscopy, field-emission scanning electron microscopy, electron back-scattered diffraction, and X-ray diffraction in order to define the microstructural changes that influenced the properties of the ADI. The obtained results show that the deep cryogenic treatment, in combination with different tempering temperatures, affects the matrix microstructure of the austempered ductile iron, which leads to an increase in both the abrasion wear resistance and the hardness.

  13. Study of high cycle fatigue of PVD surface-modified austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Feng, H.P.; Lee, S.C.; Hsu, C.H.; Ho, J.M. [Tatung Inst. of Technol., Taipei (Taiwan, Province of China). Dept. of Mater. Eng.

    1999-05-25

    Austempered ductile iron (ADI) is made from ductile iron by an austempering treatment, and its main microstructure is ausferrite that is composed of acicular ferrite and high carbon austenite. The purpose of this experiment is to investigate the influence of different coating layers and the size of casting (mass effect) on the high-cycle fatigue properties of ADI. Specimens in two casting sizes of the same chemical composition were subjected to a high-toughness austempering treatment, then coated with TiN or TiCN hard films by a physical vapor deposition (PVD) process. The results showed that the fatigue limit of the small casting size ADI is 292 MPa for ADI coated with TiN and 306 MPa for ADI coated with TiCN, which are 16% and 22%, respectively, higher than that of the ADI without coating (251 MPa). For the large casting size ADI, the fatigue limits are 200, 214 and 217 MPa for ADI without coating, ADI coated with TiN and ADI coated with TiCN, respectively. ADI coated with TiN and with TiCN are 7% and 9% better than the uncoated. Thus, it is concluded that TiN and TiCN coatings by PVD can improve the high-cycle fatigue strength of ADI. This is due to the high surface hardness and possibly the ADI surface compressive residual stress as well. For the small casting size ADI, TiCN-coated specimens have a bit higher fatigue strengths and this might be attributed to the higher hardness of TiCN than TiN films. As to the effect of mass, it is found that the small casting size has better fatigue properties and benefits more from the coating films. This could have stemmed from the higher nodule count and its associated benefits in thinner castings. (orig.) 24 refs.

  14. Effect of laser surface hardening on the microstructure, hardness and residual stresses of austempered ductile iron grades

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, C., E-mail: csoriano@tekniker.es [Tekniker-IK4, Manufacturing Processes Department, Avda. Otaola 20, CP-20600, Eibar (Gipuzkoa) (Spain); Leunda, J.; Lambarri, J.; Garcia Navas, V.; Sanz, C. [Tekniker-IK4, Manufacturing Processes Department, Avda. Otaola 20, CP-20600, Eibar (Gipuzkoa) (Spain)

    2011-06-01

    A study of the laser surface hardening process of two austempered ductile iron grades, with different austempering treatments has been carried out. Hardening was performed with an infrared continuous wave Nd:YAG laser in cylindrical specimens. The microstructure of the laser hardened samples was investigated using an optical microscope, microhardness profiles were measured and surface and radial residual stresses were studied by an X-ray diffractometer. Similar results were achieved for both materials. A coarse martensite with retained austenite structure was found in the treated area, resulting in a wear resistant effective layer of 0.6 mm to 1 mm with a microhardness between 650 HV and 800 HV. Compressive residual stresses have been found at the hardened area being in agreement with the microhardness and microstructural variations observed. The achieved results point out that the laser surface hardening is a suitable method for improving the mechanical properties of austempered ductile irons.

  15. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    Science.gov (United States)

    Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

    2011-01-01

    An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900° C for 60 minutes and given stepped austempering treatment at 280° C for 30 minutes and 60 minutes followed by 380° C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

  16. Effect of sub-zero cooling on microstructure and mechanical properties of a low alloyed austempered ductile iron

    Institute of Scientific and Technical Information of China (English)

    S. Yazdani; M. Ardestani

    2007-01-01

    The effect of sub-zero cooling on microstructure and mechanical properties of a low alloyed austempered ductile iron has been investigated. Austempering of samples was performed at 325 ℃ and 400 ℃after austenitizing at 875 ℃ and 950 ℃. The sub-zero treatments were carried out by cooling down the samples to -30 ℃, -70 ℃ and -196 ℃. The changes in volume fraction of austenite and mechanical properties were determined after cooling to each temperature. The austenite volume fraction of samples which were austenitized at 875 ℃ and austempered at 325 ℃ remained unchanged, whilst it reduced in samples austenitized at 950 ℃ and 875 ℃ for austempering temperature of 400 ℃. In these specimens, some austenite transformed to martensite after subzero cooling. Mechanical property measurements showed a slight increase in strength and hardness and decrease in elongation and toughness due to this transformation behavior.

  17. Effect of sub-zero cooling on microstructure and mechanical properties of a low alloyed austempered ductile iron

    Directory of Open Access Journals (Sweden)

    M. Ardestani

    2007-05-01

    Full Text Available The effect of sub-zero cooling on microstructure and mechanical properties of a low alloyed austempered ductile iron has been investigated. Austempering of samples was performed at 325! and 400℃ after austenitizing at 875℃ and 950℃. The sub-zero treatments were carried out by cooling down the samples to -30℃, -70℃ and -196℃. The changes in volume fraction of austenite and mechanical properties were determined after cooling to each temperature. The austenite volume fraction of samples which were austenitized at 875℃ and austempered at 325℃ remained unchanged, whilst it reduced in samples austenitized at 950℃ and 875℃ for austempering temperature of 400℃. In these specimens, some austenite transformed to martensite after subzero cooling. Mechanical property measurements showed a slight increase in strength and hardness and decrease in elongation and toughness due to this transformation behavior.

  18. The effect of segregation on the austemper transformation and toughness of ductile irons

    Science.gov (United States)

    Lin, B. Y.; Chen, E. T.; Lei, T. S.

    1998-06-01

    The effect of segregation of alloying elements on the phase transformation of ductile iron during austempering was investigated. Four heats, each containing 0.4%Mn, 1% Cu, 1.5% Ni, or 0.4% Mo (wt%) separately, were melted; then three different sizes of casting bars (3,15, and 75 mm diameter) were poured from each heat. The distribution and the degree of segregation of certain elements were quantitatively analyzed using an electron microprobe. A personal computer (PC)-controlled heat treating system was used to measure electrical resistivity, and the information on resistivity variations was used to analyze the effect of segregation on phase transformations during austempering. Also, Charpy impact and Rockwell hardness tests were performed to determine the effect of segregation on properties. Results of the electron microprobe analysis showed that the degree of segregation of alloy elements increases with an increase in diameter of the casting bars (i.e., an increase of solidification time of castings). The degree of segregation of alloy elements, represented by segregation ratio (SR) (the maximum concentration of element in cell divided by the minimum concentration of element in cell), varied linearly with the casting modulus (M) (volume of casting divided by surface area of casting). Regarding the segregating tendency among alloy elements, positive segregating elements Mn and Mo showed more segregation than the negative segregating elements Si, Cu, and Ni. In addition, segregation of Mo was more significant than Mn, and that for Cu was greater than Ni and Si. Between the time of finishing the first stage and beginning the second stage of bainite reaction in ductile irons, there is a significant “processing window,” At;, for austempering to obtain optimum mechanical properties. From the electrical resistivity data, it was observed that the austempering temperature plays a major role in the processing window. There was a narrow window at 400 ‡C but a larger

  19. Influence of a novel two-step austempering process on the strain-hardening behavior of austempered ductile cast iron (ADI)

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jianghuai; Putatunda, Susil K

    2004-09-25

    An investigation was carried out to examine the influence of a novel two-step austempering process on the strain-hardening behavior of austempered ductile cast iron (ADI). Strain-hardening exponent (n value) of specimens austempered by conventional single-step austempering process as well as the novel two-step process were determined over the entire plastic deformation regions of the stress-strain curves. Optical microscopy and X-ray diffraction analysis were performed to examine mechanisms of strain-hardening behavior in ADI under monotonic (tensile) loading. Test results show that this novel two-step process has resulted in improved microstructural variables in the ADI matrix, and higher hardness, yield strength and tensile strengths, but lower ductility and strain-hardening exponent values compared to the conventional single-step austempering process. Test results also indicate that strain-hardening exponent of ADI is a function of amount and morphology of microstructural constituents and interaction intensities between carbon atoms and dislocations in the matrix.

  20. Comparing the possibilities of austenite content determination in austempered ductile iron

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2011-07-01

    Full Text Available The article presents various methods for assessment of the austenite volume fraction in Austempered Ductile Iron (ADI. Tests were carried out on two types of ADI, i.e. unalloyed and alloyed with the addition of 0.72%Cu and 0.27%Mo, heat treated under different conditions of isothermal transformation to obtain different austenite volume fractions. The test material was then subjected to metallographic examinations, X-ray diffraction (XRD analysis, an analysis using the author's genuine programme of artificial neural networks, image analysis and magnetic measurements. The results were compared with each other indicating the possibility of a quantitative measurement of austenite and other phases present in cast iron. It was found that different methods of measurement are not fully consistent with each other but show similar results of the austenite content.

  1. Determination of the fatigue limit of an austempered ductile iron using thermal infrared imagry

    Science.gov (United States)

    Geraci, Alberto L.; La Rosa, Guido; Risitano, Antonino; Grech, Maurice

    1995-12-01

    Previous work by the authors showed that the endurance limit of specimens, or mechanical components, can be predicted using thermal infrared imagery. The new technique enables the determination of the fatigue strength limit in a comparatively short period of time (few thousands cycles), and using very few specimens (theoretically only 1). The present work applies this technique to rotating-bending test specimens of austempered ductile iron, an alloy whose fatigue limit is, due to the high scatter dispersion of the data points and the long testing period required, generally difficult to determine by the traditional technique. This material exhibited higher fatigue strength than the familiar nodular cast iron. This was confirmed by the results derived from the traditional Wohler test and the new technique, and supported by the data gathered from literature.

  2. Effect of initial microstructure on the activation energy of second stage during austempering of ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Cambranis, R.E.; Narvaez Hernandez, L. [UASLP, San Luis Potosi (Mexico). Instituto de Metalurgia; Cisneros-Guerrero, M.M. [Inst. Tecnologico de Saltillo (Mexico). Dept. Metal-Mecanica; Perez-Lopez, M.J. [Inst. Tecnologico de Zacatecas (Mexico)

    1998-03-13

    The good balance among mechanical properties of austempered ductile irons (ADI) mainly depends on the matrix microstructure, which basically consists of acicular ferrite and carbon-enriched austenite. This structure is produced by isothermal transformation of the austenite over the temperature range of 523 to 673 K. It is well accepted that during the isothermal holding, the transformation takes place in two stages. In the first stage, the austenite decomposes into acicular ferrite and carbon-enriched austenite. When the austenite is transformed at temperatures higher than 623 K, the acicular ferrite is free of carbides; at temperatures below 623 K, besides the formation of the acicular ferrite and austenite, precipitation of carbides takes place over the plates of the acicular ferrite. The mixture of ferrite and austenite is known as ausferrite being the responsible for the good mechanical properties of ADI. In this work, the ausferrite obtained above and below 623 K will be termed high and low temperature ausferrite respectively. Although ausferrite does not transform at room temperature, it is not a thermodynamically stable structure. Consequently, if the isothermal holding is extended, or if ADI is heated at high temperatures (523 to 800 K), the second stage of the austempering reaction will occur. During this stage, the carbon rich austenite will decompose into ferrite and carbides. In order to establish the maximum working temperature of ADI, it is necessary to characterize the thermal stability of ausferrite microstructure, since once stage II takes place, the mechanical properties, in particular ductility and toughness, are adversely affected. In the present work the influence of previous ausferrite microstructure (that obtained during first stage) of an alloyed ductile iron (0.6%Ni, 0.15%Mo) on the empirical activation energy of stage II is studied.

  3. Machinability of Austempered Ductile Iron (ADI) Produced by Integrated Green Technology of Continuous Casting-Heat Treatment Processes

    Science.gov (United States)

    Meena, A.; El Mansori, M.; Ghidossi, P.

    2011-01-01

    This study presents the novel processing technique known as continuous casting-heat treatment processes to produce Austempered Ductile Iron (ADI) which is a new class of ductile iron. ADI is characterized by improved mechanical properties but has low machinability as compared to other cast irons and steel of similar strength. The novel technique is developed by the integration of casting (in die casting) and heat treatment processes in foundry to save cost energy and time. Specimens just after casting were austenitized at 930° C for 90 min and then austempered in fluidized bed at 380° C for 90 and 120 min. Hence, the effect of austempering time on the morphology of retained austenite and mechanical properties of the material were examined and compared with conventionally produced ADI. Drilling tests were then carried out to evaluate the machinability of ADI in terms of cutting forces, chip micro-hardness, chip morphology and surface roughness. The mechanical properties of ADI austempered for 120 min have found to be better as compare to the ADI austempered for 90 min.

  4. Mechanisms of poor machinability of austempered ductile iron; Austemper kyujo kokuen chutetsu no nansaku kiko

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, S.; Miyaji, H. [National Research Institute for Metals, Tsukuba (Japan); Nakajima, H. [Hosei University, Tokyo (Japan)

    1995-07-01

    For the purpose of high strength distempered ductile iron (ADD) has the potential to reduce the size and weight of automotive parts, however poor machinability has made it difficult to achieve broad commercial application. To clarify the mechanism of poor machinability of ADI, (1) the chips was analyzed by X-ray diffraction, (2) the cutting front was observed after instantaneously stopping using a quick stop device, (3) for the turning tool wear was measured and (4) sawability of material was compared using a saw test. The results were as follows: In the low cutting-speed range, it was fount teat strain induced transformation from retained austerity ({gamma}R) to martensite ({alpha}{prime}) occurred, and this corresponded to the poorest machinability in the saw test. In the high cutting-speed range. {gamma}R{yields}{alpha}{prime} transformation was limited to the damaged layer, because the temperature of chips exceeded Md point. The tool wear during turning of ADI was generated closer to the cutting edge, as compared with turning of steels. Observation of chip forming state showed that this phenomenon resulted from the following two factors: (a) the formation of saw-tooth like chips ant the decrease of the tool-chip contact length due to the spheroidal graphite, and (b) the increase of cutting force due to the high hardness of the bainitic phase and the damaged layer hardened by the {gamma}R{yields}{alpha}{prime} transformation. 24 refs., 9 figs., 3 tabs.

  5. Effect of tempering treatment on toughness of austempered ductile iron; Austemper kyujo kokuen chutetsu no jinsei ni oyobosu yakimodoshi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, S.; Kobayashi, T. [Toyohashi University of Technology, Aichi (Japan)

    1994-07-25

    Austempered ductile iron (ADI) is increasing its application to high strength members as a cast iron material that has both high strength and ductility. In order to investigate the effect of internal strain generated during austempering treatment, the present study investigates the effect of tempering on its toughness, and performs metal structural discussions. The result may be summarized as follows: the cause to bring about change in toughness given by the tempering is mainly the increase or decrease in the ductility, and the optimal tempering condition was found 723K {times} 10 min in the present study; the tempering process of ADI consists of two stages, whereas in the first stage the dislocation of high density introduced by the austempering treatment is reduced mainly in the ferrite, and the toughness improves as a result of increased ductility; in the second stage, deposition of carbide (Fe3C) is developed in association with decomposition of the residual austenite, when the toughness decreases. 18 refs., 11 figs., 1 tab.

  6. Austempered Ductile Iron Manufacturing Data Acquisition Process with the Use of Semantic Techniques

    Directory of Open Access Journals (Sweden)

    Wilk-Kołodziejczyk D.

    2016-12-01

    Full Text Available The aim of this work was to propose a methodology supporting the task of collecting the comparative data on studies of the mechanical properties of ADI. Collecting of research data is an important step in the process of finding the optimum design solutions for newly made products - experimental data allow us properly calibrate the manufacturing process of ADI to let the final product achieve the required properties. Parameters of the ADI production process, i.e. the time and temperature of austenitising and austempering, as well as the alloying elements added to ductile iron affect the ADI properties. The design process can use research data collected, among others, from the Web. As stated in the article, the process of data acquisition can be supported by semantic technologies, including ontologies which are descriptive logic formalism.

  7. Numerical Simulation of Austempering Heat Treatment of a Ductile Cast Iron

    Science.gov (United States)

    Boccardo, Adrián D.; Dardati, Patricia M.; Celentano, Diego J.; Godoy, Luis A.; Górny, Marcin; Tyrała, Edward

    2016-02-01

    This paper presents a coupled thermo-mechanical-metallurgical formulation to predict the dimensional changes and microstructure of a ductile cast iron part as a consequence of an austempering heat process. To take into account the different complex phenomena which are present in the process, the stress-strain law and plastic evolution equations are defined within the context of the associate rate-independent thermo-plasticity theory. The metallurgical model considers the reverse eutectoid, ausferritic, and martensitic transformations using macro- and micro-models. The resulting model is solved using the finite element method. The performance of this model is evaluated by comparison with experimental results of a dilatometric test. The results indicate that both the experimental evolution of deformation and temperature are well represented by the numerical model.

  8. Design and control of chemical compositions for high-performance austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Gong Wenbang

    2012-05-01

    Full Text Available This paper presents the effects of chemical compositions of austempered ductile iron (ADI on casting quality, heat treatment process parameters and mechanical properties of final products. Through experiment and production practice, the impacts of carbon equivalent on ADI and its mechanical properties have been studied. Proper content ranges for carbon and silicon have been obtained to avoid ADI casting shrinkage and graphite floatation, as well as to achieve the optimal mechanical properties. According to the impact of silicon content on austenite phase transformation, the existing form of carbon in ADI has been analyzed, and also the formula and diagram showing the relationship between austenitizing temperature and carbon content in austenite have been deduced. The chemical composition range for high performance ADI and its control points have been recommended, to serve as a reference for production process.

  9. Mathematical modeling of localized melting around graphite nodules during laser surface hardening of austempered ductile iron

    Science.gov (United States)

    Roy, A.; Manna, I.

    2000-10-01

    An attempt has been made to mathematically predict the optimum conditions of laser surface hardening (LSH) of austempered ductile iron (ADI) that can ensure a predominantly martensitic microstructure and preclude partial/complete dissolution of graphite nodules in the laser hardened zone during laser irradiation. The exercise involves prediction of the thermal profile (using the Ashby and Easterling model), and consequently, the carbon diffusion profile around the graphite nodules at different depths from the surface for the given conditions of LSH. Microstructural investigations have been carried out by optical and scanning electron microscopy to study the morphology, shape and width of the partially/completely melted graphite nodules as a function of the LSH parameters. Finally, the predicted maximum width of the melted zone around the graphite nodules is compared with the relevant experimental data to validate the proposed model.

  10. Anti-friction Coating for Drilling of Green Austempered Ductile Iron (ADI) grade

    Science.gov (United States)

    Meena, A.; El Mansori, M.; Ghidossi, P.; Mkaddem, A.

    2011-05-01

    In this paper the anti-friction performance of two types of coating, post-coated coating and PVD-TiAlN coating were investigated when drilling green austempered ductile iron (ADI) grade. The green ADI grade is produced by a new processing technology known as continuous casting-heat treatment process. The effect of coatings on tool wear and surface finish of the holes when drilling using coolant were reported. Results showed that the tool with post-coated coating has higher anti-friction properties as compared to PVD-TiAlN coating in terms of tool wear and surface roughness. Results also showed that there is a formation of preventive aluminum oxide layer during machining for both types of coating.

  11. Fatigue of Austempered Ductile Iron with Two Strength Grades in Very High Cycle Regime

    Science.gov (United States)

    Zhang, Jiwang; Li, Wei; Song, Qingpeng; Zhang, Ning; Lu, Liantao

    2016-03-01

    In this study, Austempered ductile irons (ADIs) with two different strength grades were produced and the fatigue properties were measured at 109 cycles. The results show that the S-N curves give a typical step-wise shape and there is no fatigue limit in the very high cycle fatigue regime. The two grades ADI have the similar fracture behaviors and fatigue failure can initiate from defects at specimen surface and subsurface zone. On the fracture surfaces of some specimens, the `granular-bright-facet' area with rich carbon distribution is observed in the vicinity of the defect. The microstructure affects the crack behaviors at the early propagation stage. The ADI with upper and lower bainite shows higher fatigue strength compared with the ADI with coarse upper bainite.

  12. Bainitic transformation in austempered ductile iron with reference to untransformed austenite volume phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadabadai, M.N. [Tehran Univ. (Iran, Islamic Republic of)

    1997-10-01

    Much interest has been focused on austempered ductile iron (ADI) because of its superior mechanical properties, which might be improved by further control of microstructure. It has so far been assumed that segregation of alloying elements in the intercellular region just delays bainitic reaction in these regions. However, the existence of bainite-free regions (UAV) even after 10,000 minutes at test temperature, e.g., 375 C, indicates something intrinsic to the mechanism of bainitic transformation. The bainitic transformation start (B{sub s}) temperature is a function of alloying elements; segregation of alloying elements can also alter the B{sub s} temperature. In other words, B{sub s} temperature in the region near graphite should be different from the intercellular region. Therefore, the intercellular region with higher concentration of alloying elements such as Mn should have a lower B{sub s} temperature, which leads to formation of UAV even after a long high-temperature austempering time (hereafter, this stable UAV will be named as the minimum UAV value). To examine this concept, theoretical and experimental procedures were employed.

  13. The influence of chromium on mechanical properties of austempered ductile cast iron

    Science.gov (United States)

    Bartosiewicz, L.; Singh, I.; Alberts, F. A.; Krause, A. R.; Putatunda, S. K.

    1995-02-01

    An investigation was carried out to examine the influence of microstructure and chromium on the tensile properties and plane strain fracture toughness of austempered ductile cast iron (ADI). The investigation also examined the growth kinetics of ferrite in these alloys. Compact tension and round cylindrical tensile specimens were prepared from ductile cast iron with Cr as well as without Cr. These specimens were then given four different heat treatments to produce four different microstructures. Tensile tests and fracture toughness tests were carried out as per ASTM standards E-8 and E-399. The crack growth mechanism during fracture toughness tests was also determined. The test results indicate that yield strength, tensile strength, and fracture toughness of ADI increases with an increase in the volume fractions of ferrite, and the fracture toughness reaches a peak when the volume fractions of the ferrite are approximately 60% in these alloys. The Cr addition was found to reduce the fracture toughness of ADI at lower hardness levels (<40 HRC); at higher hardness levels (≥40 HRC), the effect of chromium on the fracture toughness was negligible. The crack growth mechanism was found to be a combination of quasi-cleavage and microvoid coalescences, and the crack trajectories connect the graphite nodules along the way.

  14. Effect of low temperatures on charpy impact toughness of austempered ductile irons

    Science.gov (United States)

    Riabov, Mikhail V.; Lerner, Yury S.; Fahmy, Mohammed F.

    2002-10-01

    Impact properties of standard American Society for Testing Materials (ASTM) grades of austempered ductile iron (ADI) were evaluated at subzero temperatures in unnotched and V-notched conditions and compared with ferritic and pearlitic grades of ductile irons (DIs). It was determined that there is a decrease in impact toughness for all ADI grades when there is a decrease in content of retained austenite and a decrease in test temperature, from room temperature (RT) to -60 °C. However, the difference in impact toughness values was not so noticeable for low retained austenite containing grade 5 ADI at both room and subzero temperatures as it was for ADI grade 1. Furthermore, the difference in impact toughness values of V-notched specimens of ADI grades 1 and 5 tested at -40 °C was minimal. The impact behaviors of ADI grade 5 and ferritic DI were found to be more stable than those of ADI grades 1, 2, 3, and 4 and pearlitic DI when the testing temperature was decreased. The impact toughness of ferritic DI was higher than that of ADI grades 1 and 2 at both -40 °C and -60 °C. The impact properties of ADI grades 4 and 5 were found to be higher than that of pearlitic DI at both -40 °C and -60 °C. The scanning electron microscopy (SEM) study of fracture surfaces revealed mixed ductile and quasicleavage rupture morphology types in all ADI samples tested at both -40 °C and -60 °C. With decreasing content of retained austenite and ductility, the number of quasicleavage facets increased from ADI grade 1-5. It was also found that fracture morphology of ADI did not experience significant changes when the testing temperature decreased. Evaluation of the bending angle was used to support impact-testing data. Designers and users of ADI castings may use the data developed in this research as a reference.

  15. The Effect of Isothermal Heat Treatment Time on the Microstructure and Properties of 2.11% Al Austempered Ductile Iron

    Science.gov (United States)

    Erfanian-Naziftoosi, H. R.; Haghdadi, N.; Kiani-Rashid, A. R.

    2012-08-01

    In this article, the bainitic transformation during austempering was studied for a 2.11% Al containing ductile iron under different isothermal holding times. The austenitizing time and temperature were selected to be 60 min and 920 °C, respectively, referring to previous studies. The isothermal austempering heat treatments were performed at 350 °C for different durations. Microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural investigations revealed that austempering treatment at 350 °C for durations up to 100 min results in microstructures consisting of carbide-free bainitic ferrite with considerable amounts of retained austenite while the extension of isothermal transformation time leads to precipitation of carbides. Hardness measurements were also carried out the results of which were shown to be consistent with microstructural evolutions.

  16. The effect of manganese on the onset of the stage 2 reaction in an austempered ductile iron matrix

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, K. N.

    1990-02-01

    Austempered ductile irons (ADIs) possess a unique combination of toughness and ductility plus high strength which make them attractive alternatives to other metal castings. ADIs can have tensile strengths up to 230 ksi with a 1% elongation and high hardness for wear resistant applications, or tensile strengths of approximately 150 ksi and elongations of 14% where a large amount of ductility is required. Austempering is a two step process: complete transformation to the austenite ({gamma}) phase; and a quench and hold in the temperature range of 270--420{degree}C for some time followed by cooling to room temperature. This quench must be sufficiently rapid to avoid formation of pearlite or ferrite if the best mechanical properties are to be obtained. This thesis presents the results of a number of experiments aimed at determining the effect of Mn on the length of the Stage 1 reaction. (austenite decomposes into bainitie ferrite and high carbon austenite). A basic knowledge of the effects of Mn will yield a more complete understanding of the austempering process for the normal case and also when microsegregation is present. The onset time for Stage 2 (high carbon austenite decomposes into bainitic ferrite plus carbides) in ductile irons is a critical parameter because of the associated degradation of the mechanical properties which result from carbide formation.

  17. Material Characterization of Austempered Ductile Iron (ADI) Produced by a Sustainable Continuous Casting-Heat Treatment Process

    Science.gov (United States)

    Meena, Anil; El Mansori, Mohamed

    2012-12-01

    Selecting a suitable manufacturing process is one way of achieving sustainability of a product by diminishing energy consumption during its production cycle and improving material efficiency. The article attempts to explore the new processing technology for direct manufacturing of lightweight austempered ductile iron (ADI) casting in a permanent mold. The new processing technology is based on the innovative integrated approach toward casting and heat-treatment process. In this technology, the ductile iron samples obtained using the permanent mold are first austenized immediately after solidification process followed by austempering heat treatment in the fluidized bed and then air cooled at room temperature to obtain ADI material. The influence of austempering time on the microstructural characteristics, mechanical properties, and strain-hardening behavior of ADI was studied. Optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were performed to correlate the mechanical properties with microstructural characteristics. It was observed that the mechanical properties of resulting ADI samples were influenced by the microstructural transformations and varied retained austenite volume fractions obtained due to different austempering time. The results indicate that the strain-hardening behavior of the ADI material is influenced by the carbon content of retained austenite.

  18. Effects of subzero treatment on toughness of austempered ductile cast iron; Austemper kyujo kokuen chutetsu no jinsei ni oyobosu subzero shori no koka

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, S.; Yamada, S. [Kanto Gakuin University, Yokohama (Japan)

    1998-04-25

    Specimens of austempered ductile cast iron (ADI) after constant temperature transformation at different temperatures are tested for tension, shock, and bending, and the effects of the testing methods and testing speeds on ADI strength and toughness are investigated. Specimens are made of an austempered Fe-Si-Mg alloy cast into 25mm-thick Y-shape blocks. Heat treatment is performed in the atmosphere for test pieces manufactured by machining. In the subzero treatment, the austempered pieces are cooled in water and then immediately placed in liquid nitrogen for rapid cooling. Findings obtained are mentioned below. A test piece austempered at 773K and then cooled in water retains 26% of austenite, and this disappears after a tension test. In a test piece given subzero treatment following the cooling in water, the residual austenite is found reduced from 20% to 13%. No change is observed in the amount of residual austenite before and after a bend test and impact test whether or not the test piece has been subjected to subzero treatment. 8 refs., 8 figs., 2 tabs.

  19. Effects of austempering heat treatment conditions on fracture toughness of austempered ductile cast iron; Kyujo kokuen chutetsu no hakai jinsei ni oyobosu austemper shori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Y.; Arai, M. [Musashi Institute of Technology, Tokyo (Japan)

    1996-03-25

    Discussions were given in various manners to learn effects of treatment conditions with respect to fracture toughness of austempered ductile cast iron. Austenitizing temperature and isothermal transforming conditions that result in comprehensively most excellent fracture toughness including tensile strength were 1173 K and 648 K - 3.6 ks, respectively. The austenitizing temperature as low as 1123 K reduces quantity of residual austenite, resulting in residual inclusion of free ferrite in the structure. If as high as 1223 K, reduction in the fracture toughness is caused under any condition as a result of increase in unstable austenite and growth of austenite into coarse particles. With respect to the isothermal transforming conditions, high fracture toughness may be achieved at a relatively high temperature. However, a structure that has been transformed from austenite to bainite causes a secondary reaction in a short time, and deposits particulates of cementite and graphite, leading to a prediction of decrease in the fracture toughness. Therefore, it is preferable that the treatment time is decreased in order to suppress the secondary reaction. 9 refs., 10 figs., 7 tabs.

  20. Influence of Heat Treatment Conditions on Microstructure and Mechanical Properties of Austempered Ductile Iron After Dynamic Deformation Test

    Directory of Open Access Journals (Sweden)

    Myszka D.

    2014-10-01

    Full Text Available In this article, an attempt was made to determine the effect of dynamic load on the austempered ductile iron resistance obtained under different conditions of heat treatment. Tests were carried out on six types of cylindrical ductile iron samples austempered at 320, 370 and 400oC for 30 and 180 minutes. For each type of material, two samples were collected. As a next step in the investigations, the samples were subjected to a Taylor impact test. The samples after striking a non-deformable, rigid target were deformed on their front face. After Taylor test, a series of material tests was performed on these samples, noting a significant increase of hardness in the deformed part. This was particularly well visible in the ductile iron isothermally quenched at higher temperatures of 370 and 400oC. Inthezone of sample deformation, an increase in the content of ferromagnetic phase was also reported, thus indicating the occurrence of martensitic transformation in the microstructure containing mechanically unstable austenite. A significant amount of deformed graphite was also observed, which was a symptom of the deformation process taking place in samples. The ductile iron was characterized by high toughness and high resistance to the effect of dynamic loads, especially as regards the grade treated at a temperature of 370oC.

  1. Effects of heat treatment on toughness of austempered ductile cast iron with Cu and Ni; Cu-Ni tenka osutenpa chutetsu no jinsei ni oyobosu netsushori no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, M.; Takatsu, M.; Takagi, H

    1998-08-25

    The alloying of ductile cast iron with Cu and Ni is effective for the structural control in austemper heat treatment. Use of this type of cast iron is provided to produce cast iron materials with extremely high toughness and strength. In this study, the effects of austempering conditions and the addition of Cu and Ni on toughness of ductile cast iron are investigated. In austemper heat treatment, impact absorbed energy is increased by raising the austempering temperature. However, at high austempering temperatures exceeding 3.6 ks at 673K, the formation of fine pearlite proceeded, resulting in a marked decrease in the impact absorbed energy. Addition of Cu-Ni in the cast iron resulted in greater impact absorbed energy and tensile strength at any temperature during the austempering treatment. It depends on the suppression of precipitation beginning of fine pearlite and the stabilization of retained austenite. Furthermore, this cast iron alloy reduced the change in impact absorbed energy and tensile strength, induced during the austempering time. 15 refs., 12 figs., 1 tab.

  2. A study of several factors governing the fatigue limits of austempered ductile cast iron with various microstructures

    Science.gov (United States)

    Kim, Jinhak; Kim, Sangtae; Kim, Mingun

    2000-06-01

    The effects the leading factors bearing on fatigue limits were investigated with three kinds of ductile iron specimens various microstructures. As a result of examination, the fatigue limits in relationship to hardness and tensile strength, the expected higher improvement for fatigue limits in the case of the high strength specimens that experienced austempering treatment are not observed in comparison with the specimens treated with stress relief treatment. The estimated maximum defect size is one of the important parameters in predicting and evaluating fatigue limits for three different heat-treated ductile cast irons. Also, a quantitative relationship can be established between the fatigue limit and maximum defect size. Moreover, it is possible to explain the difference in fatigue limits in the three ductile cast irons by application of the rates of non-propagating crack which connects the adjacent graphite nodules before it stops.

  3. Characterization of microstructural morphology of austempered ductile iron by electron microscopy.

    Science.gov (United States)

    Guo, X L; Su, H Q; Wu, B Y; Liu, Z G

    1998-02-15

    Mechanical properties of austempered ductile iron (ADI) are mainly controlled by its unique microstructure. The objectives of this paper are to characterize the microstructural morphology and the phase distribution of ADI using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and to determine the mechanism of strengthening and toughening of ADI. The experimental results show that, in the microstructure of ADI composing of upper bainite, retained austenite, graphitic nodule, and a small amount of martensite, the upper bainite is composed of sub-units of ferrite in the shape of "wheat ears" on which the "wheat grains" grow at an angle of about 60 degrees to the long axis of the "wheat ears." The retained austenite is connected with each other in the shape of a continuous net. The wheat-ear like bainite with a homogeneous distribution in the continuous austenite net plays an important role to the strengthening and toughening of ADI. The metastable austenite appears in the shape of a large plate in which the martensite is preferentially formed. The appearance of martensite can be suppressed at the time when retained austenite remains stable, which is of benefit to the continuity and homogeneity of austenite net.

  4. Comparison of High-Temperature Properties and Thermal Shock Resistance of Austempered Ductile Irons (ADI) with Those of Pearlitic Ductile Cast Irons

    Science.gov (United States)

    Ajabshiri, Mehrdad; Sharafi, Shahriar; Moeini, Alireza

    2012-01-01

    High-temperature strength and thermal shock resistance of austempered ductile iron (ADI) in high temperatures because of instability of ausferrite phase has been less interest. The aim of this study is to investigate the tensile properties of ADI and pearlitic ductile cast iron by using the short-time tensile test in high temperatures. Tensile test was conducted in temperatures of 298 K, 673 K, 873 K, and 1073 K (25 °C, 400 °C, 600 °C, and 800 °C). Thermal shock test also was conducted by using the molten lead bath at 1273 K (1000 °C). In this experiment, samples of pearlitic ductile cast iron and ADI were divided in two groups; that after immersing in the molten lead bath for 25 seconds, one group was cooled in the air and other one was quenched in the water. Results showed that strength and thermal shock resistance of ADI samples are higher than those of the pearlitic ductile cast iron.

  5. The Strain-Hardening Behavior of Partially Austenitized and the Austempered Ductile Irons with Dual Matrix Structures

    Science.gov (United States)

    Kilicli, Volkan; Erdogan, Mehmet

    2008-04-01

    In the current study, an unalloyed ductile iron containing 3.50 C wt.%, 2.63 Si wt.%, 0.318 Mn wt.%, and 0.047 Mg wt.% was intercritically austenitized (partially austenitized) in two-phase regions (α + γ) at different temperatures for 20 min and then was quenched into salt bath held at austempering temperature of 365 °C for various times to obtain different ausferrite plus proeutectoid ferrite volume fractions. Fine and coarse dual matrix structures (DMS) were obtained from two different starting conditions. Some specimens were also conventionally austempered from 900 °C for comparison. The results showed that a structure having proeutectoid ferrite plus ausferrite (bainitic ferrite + high-carbon austenite (retained or stabilized austenite)) has been developed. Both of the specimens with ˜75% ausferrite volume fraction (coarse structure) and the specimen with ˜82% ausferrite volume fraction (fine structure) exhibited the best combination of high strength and ductility compared to the pearlitic grades, but their ductility is slightly lower than the ferritic grades. These materials also satisfy the requirements for the strength of the quenched and tempered grades and their ductility is superior to this grade. The correlation between the strain-hardening rates of the various austempered ductile iron (ADI) with DMS and conventionally heat-treated ADI microstructures as a function of strain was conducted by inspection of the respective tensile curves. For this purpose, the Crussard-Jaoul (C-J) analysis was employed. The test results also indicate that strain-hardening behavior of ADI with dual matrix is influenced by the variations in the volume fractions of the phases, and their morphologies, the degree of ausferrite connectivity and the interaction intensities between the carbon atoms and the dislocations in the matrix. The ADI with DMS generally exhibited low strain-hardening rates compared to the conventionally ADI.

  6. Effect of austempering process on microstructure and wear behavior of ductile iron containing Mn-Ni-Cu-Mo

    Science.gov (United States)

    PourAsiabi, HaMiD; Saghafian, Hasan; Pourasiabi, Hamed

    2013-01-01

    In this work, the effects of austempering time and temperature on the microstructure and sliding wear behavior of a Mn-Ni-Cu-Mo alloyed ductile iron were investigated. Ductile iron samples with the desired chemical composition were cast according to ASTM A897M-1990 Y-block. Wear test samples austenitized at 900 °C for 90 min, were austempered at 260, 290 and 320 °C for 30, 60, 90 and 120 min. The wear tests on samples were conducted by Block-on-Ring testing machine according to ASTM G77-98 standard, at the applied load of 75N and the displacement speed of 3.27 m/s. The results showed that the sample austempered at 260 °C for 90 min exhibited the maximum relative wear resistance in comparison with the as-cast sample. The X-ray diffraction patterns of wear debris and the SEM observations of worn surfaces and crosssection of worn surfaces together with wear debris showed that delamination associated with oxidation is the dominant wear mechanism in the samples.

  7. Effect of Holding Time in the (α + γ) Temperature Range on Toughness of Specially Austempered Ductile Iron

    Science.gov (United States)

    Kobayashi, Toshiro; Yamada, Shinya

    1996-07-01

    Austempered ductile iron (ADI) finds wide application in the industry because of its high strength and toughness. The QB' process has been developed to produce a fine microstructure with high fracture toughness in ADI. This process involves reaustenitizing a prequenched ductile iron in the (α + γ) temperature range followed by an isothermal treatment in the bainitic transformation tem-perature range. In the present work, the effect of holding time in the (α + γ) temperature range on the structure and un-notched toughness of ADI has been studied. Prior to the austempering treatment, the as-cast ductile iron was heat treated to obtain martensitic, ferritic, and pearlitic matrix structures. In the case of prequenched material (martensitic matrix), the un-notched impact toughness increased as a function of holding time in the (α + γ) temperature range. The reaustenitization heat treatment also resulted in the precipitation of fine carbide particles, identified as (Fe,Cr,Mn)3C. It was shown that the increase in holding time in the (α + γ) temperature range leads to a reduction in the number of carbide particles. In the case of a ferritic prior structure, a long duration hold in the (α + γ) temperature range resulted in the coarsening of the structure with a marginal increase in the tough-ness. In the case of a pearlitic prior structure, the toughness increased with holding time. This was attributed to the decomposition of the relatively stable carbide around the eutectic cell boundary with longer holding times.

  8. Effect of holding time in the ({alpha} + {gamma}) temperature range on toughness of specially austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, T.; Yamada, S. [Toyohashi Univ. of Technology (Japan). Dept. of Production Systems Engineering

    1996-07-01

    Austempered ductile iron (ADI) finds wide application in the industry because of its high strength and toughness. The QB{prime} process has been developed to produce a fine microstructure with high fracture toughness in ADI. This process involves reaustenitizing a prequenched ductile iron in the ({alpha} + {gamma}) temperature range followed by an isothermal treatment in the bainitic transformation temperature range. In the present work, the effect of holding time in the ({alpha} + {gamma}) temperature range on the structure and un-notched toughness of ADI has been studied. Prior to the austempering treatment, the as-cast ductile iron was heat treated to obtain martensitic, ferritic, and pearlitic matrix structures. In the case of prequenched material (martensitic matrix), the un-notched impact toughness increased as a function of holding time in the ({alpha} + {gamma}) temperature range. The reaustenitization heat treatment also resulted in the precipitation of fine carbide particles, identified as (Fe,Cr,Mn){sub 3}C. It was shown that the increase in holding time in the ({alpha} + {gamma}) temperature range leads to a reduction in the number of carbide particles. In the case of a ferritic prior structure, a long duration hold in the ({alpha} + {gamma}) temperature range resulted in the coarsening of the structure with a marginal increase in the toughness. In the case of a pearlitic prior structure, the toughness increased with holding time. This was attributed to the decomposition of the relatively stable carbide around the eutectic cell boundary with longer holding times.

  9. Effect of nodule count and austempering heat treatment on segregation behavior of alloying elements in ductile cast iron

    Directory of Open Access Journals (Sweden)

    E. Akbarzadeh Chiniforush

    2016-05-01

    Full Text Available The equilibrium partition ratio, k, has been measured for Mn, Mo, Si, Ni and Cu in a ductile iron with composition (wt.%: 3.45C, 0.25Mn, 0.25Mo, 2.45Si, 0.5Ni and 0.5Cu with different nodule counts obtained from different section sizes of 13, 25, 75 mm in the as cast, austenitized (at 870 °C for times 1, 4 and 6 hours and austempered (at 375 °C for times 1 to 1,440 min samples. Results show that Mn and Mo segregate positively at cell boundaries, but Si, Ni and Cu concentrate in an inverse manner in the vicinity of graphite nodules and there is a depletion of these elements at cell boundaries. Segregation curves for Ni and Cu are more smooth than for Si. Carbide formation has been observed at cell boundaries. Based on the results, the partition ratios for all elements decrease with increasing the nodule count. More carbide with coarser morphology has been observed in the microstructure with a lower nodule count. Austenitization for a longer time can decrease partition ratio, but cannot eliminate it entirely. Increasing the austenitization temperature has the same effect. Austenitizing parameters have no significant effect on carbides volume fraction. The kinetics of austempering is faster in higher nodule counts and subsequently better mechanical properties including higher ductility, strength and toughness have been observed for all austempering conditions studied.

  10. 等温处理工艺对等温淬火球铁显微组织和硬度的影响%Effect of Austempering Technics on Microstructure and Hardness of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    亚斌; 张宝昌; 贾非; 李乃朴; 房灿峰; 郝海; 张兴国; 刘恒乐; 蔡勇; 孟宪军

    2012-01-01

    Austempered ductile iron (ADI) with high-strength and high toughness was created by method of austempering in the 1970s, which is characterized to have a tensile strength over 1000MPa, and an elongation more than 15%. With an orthogonal test and the method of austempering, the effect of the austempering technics on the microstructure and hardness of austempered ductile iron was discussed. It is found that austempered ductile iron which microstructure contains bainite and retained austenite can be gained in all of the designed austempering technics through the experiment. The hardness of samples could be mostly affected by the temperature of austempered, followed by the austenitizing temperature and austenitizing time, and the timing of austempering is proved to have the least influence on the hardness of samples.%上世纪70年代,通过奥氏体等温淬火开发出抗拉强度大于1000MPa、伸长率大于15%的高强度、高韧性等温淬火球铁。利用正交试验法,研究了等温淬火工艺参数对等温淬火球铁显微组织及硬度的影响。结果发现,在设计的试验工艺内全部可以得到以针状铁素体和富碳奥氏体为基体的等温淬火球铁组织;在等温淬火工艺中,等温淬火温度对试样硬度影响最为显著,其次是奥氏体化温度与奥氏体化时间,而等温淬火时间对于试样硬度的影响最小。

  11. Modification during heat treatment and application service of austempered ductile iron parts. ADI buhin no netsushori oyobi shiyochu no henkei

    Energy Technology Data Exchange (ETDEWEB)

    Shiokawa, T. (Subiyama Co. Ltd., Tokyo (Japan))

    1991-12-25

    Austempered ductile iron (ADI) has a very high mechanical strength, and excellent tenacity and ductility, but has also problems of dimensional changes in ADI parts. This paper describes dimensional changes in ADI parts, and further discusses points requiring cautions on dimensions when using ADI parts. To reduce dimensional changes before and after a heat treatment of an ADI, a use of ferrite is desirable as a texture before the heat treatment. Or otherwise the dimensional change due to heat treatment may be reflected initially on the dimensions before the heat treatment as an effective means of reducing the change. As an ADI varies its dimension-related thermal stability according to its chemical composition and the heat treatment method, parts that need the stability require a consideration to use a low Ni content and extend the austempering time. Since the ADI parts have different thermal expansion coefficient from the conventional ductile cast irons, parts subjected to a temperature rise should be used with considerations given to the thermal expansion difference with the mating parts. 4 refs., 4 figs., 3 tabs.

  12. 关于奥贝球铁及其微观组织术语的探讨—对ADI(AustemperedDuctileIron)我们需要一个正确的中文术语%Discussion on the Term of Austempered Ductile Iron and Its Microstructure - We need a correct Chinese term for the " austempered ductile iron"

    Institute of Scientific and Technical Information of China (English)

    刘金城

    2002-01-01

    论述了等温淬火球铁的工艺及其微观组织.分析了其微观组织与钢中贝氏体的区别.指出ADI(AustemperedDuctileIron)奥贝球铁是一个不恰当的术语.对这种新铸铁,我们需要一个正确的中文术语:奥铁球铁或者称奥氏体等温淬火球铁.

  13. Fatigue crack growth in austempered ductile and grey cast irons - stress ratio effects in air and mine water

    Energy Technology Data Exchange (ETDEWEB)

    James, M.N. [Plymouth Univ. (United Kingdom). Dept. of Mech. and Marine Eng.; Li Wenfong [Department of Mechanical Engineering, University of Sydney, Sydney, NSW 2006 (Australia)

    1999-06-15

    A study is presented of the effect of stress ratio on fatigue crack growth in grey (GI) and austempered ductile (ADI) cast irons in laboratory air and, for the ADI, in synthetic mine water. Fatigue crack closure was measured by compliance techniques and factored out of the applied {Delta}K values ({Delta}K=K{sub max}-K{sub min}) to give effective stress intensity values. Crack growth rate modelling was then attempted for the laboratory air data using a two-parameter approach ({Delta}K and K{sub max}). This worked well for the ADI, but not for the GI, probably due to the much larger scatter inherent in the fatigue crack growth rates in the latter alloy. Trends in the observed growth rate and closure data for the two alloys are explained in terms of mechanism changes arising from microstructural/crack tip plastic zone interactions, and K{sub max} effects. (orig.) 9 refs.

  14. Influence of the amount and morphology of retained austenite on the mechanical properties of an austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Aranzabal, J. [INASMET, San Sebastian (Spain); Gutierrez, I.; Rodriguez-Ibabe, J.M.; Urcola, J.J. [CEIT, San Sebastian (Spain). Dept. of Materials

    1997-05-01

    High Si contents in nodular cast irons lead to a significant volume fraction of retained austenite in the material after the austempering treatment. In the present work, the influence of the amount and morphology of this phase on the mechanical properties (proof stress, ultimate tensile strength (UTS), elongation, and toughness) has been analyzed for different austempering conditions. After 300 C isothermal treatments at intermediate times, the austenite is plastically stable at room temperature and contributes, together with the bainitic ferrite, to the proof stress and the toughness of the material. For austenite volume fractions higher than 25 pct, the proof stress is controlled by this phase and the toughness depends mainly on the stability of {gamma}. In these conditions (370 C and 410 C treatments), the present material exhibits a transformation-induced plasticity (TRIP) effect, which leads to an improvement in ductility. It is shown that the strain level necessary to initiate the martensitic transformation induced by deformation depends on the carbon content of the austenite. The martensite formed under TRIP conditions can be of two different types: autotempered plate martensite, which forms at room temperature from an austenite with a quasi-coherent epsilon carbide precipitation, and lath martensite nucleated at twin boundaries and twin intersections.

  15. Effect of austenitizing conditions on the impact properties of an alloyed austempered ductile iron of initially ferritic matrix structure

    Energy Technology Data Exchange (ETDEWEB)

    Delia, M.; Alaalam, M.; Grech, M. [Univ. of Malta (Malta). Dept. of Metallurgy and Materials

    1998-04-01

    The effect of austenitizing conditions on the microstructure and impact properties of an austempered ductile iron (ADI) containing 1.6% Cu and 1.6% Ni as the main alloying elements was investigated. Impact tests were carried out on samples of initially ferritic matrix structure and which had been first austenitized at 850, 900, 950, and 1,000 C for 15 to 360 min and austempered at 360 C for 180 min. Results showed that the austenitizing temperature, T{sub {gamma}}, and time, t{sub {gamma}} have a significant effect on the impact properties of the alloy. This has been attributed to the influence of these variables on the carbon kinetics. Microstructures of samples austenitized at 950 and 1,000 C contain no pro-eutectoid ferrite. The impact properties of the former structures are independent of t{sub {gamma}}, while those solution treated at 1,000 C are generally low and show wide variation over the range of soaking time investigated. For fully ausferritic structures, impact properties fall with an increase in T{sub {gamma}}. This is particularly evident at 1,000 C. As the T{sub {gamma}} increases, the amount of carbon dissolved in the original austenite increases. This slows down the rate of austenite transformation and results in coarser structures with lower mechanical properties. Optimum impact properties are obtained following austenitizing between 900 and 950 C for 120 to 180 min.

  16. Design and optimization of stepped austempered ductile iron using characterization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Rivera, J.L., E-mail: jose.hernandez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados-Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, Z.C. 31109, Chihuahua (Mexico); Garay-Reyes, C.G.; Campos-Cambranis, R.E.; Cruz-Rivera, J.J. [Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, Sierra Leona 550, Lomas 2a. sección, Z.C. 78210, San Luis Potosí (Mexico)

    2013-09-15

    Conventional characterization techniques such as dilatometry, X-ray diffraction and metallography were used to select and optimize temperatures and times for conventional and stepped austempering. Austenitization and conventional austempering time was selected when the dilatometry graphs showed a constant expansion value. A special heat color-etching technique was applied to distinguish between the untransformed austenite and high carbon stabilized austenite which had formed during the treatments. Finally, it was found that carbide precipitation was absent during the stepped austempering in contrast to conventional austempering, on which carbide evidence was found. - Highlights: • Dilatometry helped to establish austenitization and austempering parameters. • Untransformed austenite was present even for longer processing times. • Ausferrite formed during stepped austempering caused important reinforcement effect. • Carbide precipitation was absent during stepped treatment.

  17. Isothermal Transformation of Austempered Ductile Iron and ADI Continuous Production Line%等温淬火球铁的等温转变过程及ADI设备

    Institute of Scientific and Technical Information of China (English)

    王蕾; 吴光英

    2012-01-01

    分析了等温淬火球铁(ADI)等温转变过程及影响因素,介绍了奥一贝球铁等温淬火设备,包括推杆式、立式、箱式等温淬火连续生产线,并对国内外等温淬火生产线进行了对比。%The isothermal transformation of austempered ductile iron and main influence factors were described. The austempered ductile iron continuous production lines, including pusher type, vertical type and box type were introduced, and the ADI production lines at home and abroad were compared.

  18. Fatigue properties of austempered ductile cast iron at room and elevated temperatures; Austemper kyujo kokuen chutetsu no chukoon ni okeru hiro tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Fukuyama, K.; Hasegawa, N.; Inaga, K. [Gifu University, Gifu (Japan)

    1995-06-15

    Austempered ductile cast iron (ADI) is used widely as a structural material with high strength and toughness. However, since few studies have been made on investigation of fatigue properties at medium to high temperatures, this paper describes rotating bending tests carried out in temperature range between room temperature and 400{degree}C to investigate the fatigue properties and the fatigue crack generating behavior. The following results were obtained: the fatigue limit (fatigue strength after 10{sup 7} bendings) showed a remarkable maximizing phenomenon at temperatures around 300{degree}C; micronization of the base structure caused by transformation of residual austenite was recognized above 300{degree}C, and so was rise in the hardness; heating to this temperature led to rise in the Ms point, making the transformation occur more easily; the effect of repetitive stress causes a processing induced transformation; the temperature at which the transformation and the micronization are completed declines by about 50{degree}C lower than in the non-transformed region; and the fatigue fracture at middle to high temperatures is caused more frequently by internally existing graphite and development of cracks from very small casting cavities. 31 refs., 10 figs., 7 tabs.

  19. Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition

    Directory of Open Access Journals (Sweden)

    Myszka D.

    2015-04-01

    Full Text Available The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.

  20. Effect of austenitizing conditions on the impact properties of an alloyed austempered ductile iron of initially ferritic matrix structure

    Science.gov (United States)

    Delia, M.; Alaalam, M.; Grech, M.

    1998-04-01

    The effect of austenitizing conditions on the microstructure and impact properties of an austempered ductile iron (ADI) containing 1.6% Cu and 1.6% Ni as the main alloying elements was investigated. Impact tests were carried out on samples of initially ferritic matrix structure and which had been first austenitized at 850,900, 950, and 1000°C for 15 to 360 min and austempered at 360°C for 180 min. Results showed that the austenitizing temperature, Tγ, and time, tγ, have a significant effect on the impact properties of the alloy. This has been attributed to the influence of these variables on the carbon kinetics. The impact energy is generally high after short tγ, and it falls with further soaking. In samples austenitized at 850 and 900°C, these trends correspond to the gradual disappearance of the pro-eutectoid ferrite and the attainment of fully developed ausferritic structures. In initially ferritic structures, the carbon diffusion distances involved during austenitization are large compared to those in pearlitic structures. This explains the relatively long soaking periods required to attain fully ausferritic structures, which in spite of the lower impact energy values, have a better combination of mechanical properties. Microstructures of samples austenitized at 950 and 1000°C contain no pro-eutectoid ferrite. The impact properties of the former structures are independent of tγ, while those solution treated at 1000°C are generally low and show wide variation over the range of soaking time investigated. For fully ausferritic structures, impact properties fall with an increase in Tγ. This is particularly evident at 1000°C. As the Tγ increases, the amount of carbon dissolved in the original austenite increases. This slows down the rate of austenite transformation and results in coarser structures with lower mechanical properties. Optimum impact properties are obtained following austenitizing between 900 and 950°C for 120 to 180 min.

  1. Corrosion behaviour and structure of the surface layer formed on austempered ductile iron in concentrated sulphuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, H. [AGH University of Science and Technology, Department of Foundry Engineering, ul. Reymonta 23, 30-059 Cracow (Poland)]. E-mail: krawiec@uci.agh.edu.pl; Stypula, B. [AGH University of Science and Technology, Department of Foundry Engineering, ul. Reymonta 23, 30-059 Cracow (Poland); Stoch, J. [Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences (PAS), ul. Niezapominajek 8, 30-239 Cracow (Poland); Mikolajczyk, M. [Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences (PAS), ul. Niezapominajek 8, 30-239 Cracow (Poland)

    2006-03-15

    The aim of this paper is to investigate the structure of the surface layer formed on austempered ductile iron (ADI) after exposure to hot concentrated sulphuric acid at the open circuit potential value (OCP). The results derived from polarization measurements carried out in sulphuric acid at a temperature of 90 deg. C show that anodic dissolution of ADI is divided into three stages (corresponding to three anodic dissolution peaks). The structure of the layer formed on alloys at 90 deg. C at OCP was investigated using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). SEM analysis shows that the main elements of the surface layer are iron, silicon, oxygen, sulphur, and carbon. The binding energy recorded in individual bands indicates that the surface layer includes mainly SiO{sub 2} and FeOOH. The presence of sulphur at the lower oxidation state (S{sup 2-}) indicates that sulphuric acid undergoes reduction during this process. The corrosion resistance of these alloys is connected with the presence of SiO{sub 2} in the surface layer.

  2. Microstructures and Mechanical Properties of Helical Bevel Gears Made by Mn-Cu Alloyed Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    LIU Sheng-fa; CHEN Yang; CHEN Xin; MIAO Hua-ming

    2012-01-01

    Austempered ductile iron (ADI) has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope (OM), scanning electron microscope (SEM) and performance measurement. The results showed that after a series of treatments, the mechanical properties (Rm 1007. 4 to 1200 MPa, A 5.2% to 8. 8%, HRC 32 to HRC 35, O~K 70 to 120 J/cmz ) of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564-97/ EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate life and median life respectively exceeding 30×104 and 50 × 10^4 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.

  3. Application of austempered ductile iron for lightening the automotive chassis%高性能球墨铸铁在汽车底盘轻量化中的应用

    Institute of Scientific and Technical Information of China (English)

    吴华锋; 张金根

    2012-01-01

    Development and excellent performance of austempered ductile iron were introduced. Application trends and conditions of austempered ductile iron for the auto classis were analyzed in order, to lighten its weight. And finally, the austempered ductile iron application in practical production were introduced.%介绍了高性能球墨铸铁的发展现状及优异性能,并结合汽车轻量化需求,分析了等温淬火球墨铸铁材料在汽车底盘上的应用趋势,最后介绍了等温淬火球墨铸铁在实际生产中的应用。

  4. Effect of deep cryogenic treatment and tempering on microstructure and mechanical behaviors of a wear-resistant austempered alloyed bainitic ductile iron

    Directory of Open Access Journals (Sweden)

    Chen Liqing

    2015-01-01

    Full Text Available In this paper, the effect of deep cryogenic treatment in combination with conven- tional heat treatment process was investigated on microstructure and mechanical behaviors of alloyed bainitic ductile iron. Three processing schedules were employed to treat this alloyed ductile iron including direct tempering treatment, tempering.+deep cryogenic treatment and deep cryogenic treatment.+tempering treatments. The microstructure and mechanical behavior, especially the wear resistance, have been evaluated after treated by these three schedules. The results show that martensite microstructure can be obviously refined and the precipitation of dispersed carbides is promoted by deep cryogenic treatment at .−196 ∘C for 3 h after tempered at 450 ∘C for 2 h. In this case, the alloyed bainitic ductile iron possesses rather high hardness and wear-resistance than those processed by other two schedules. The main wear mechanism of the austempered alloyed ductile iron with deep cryogenic treatment and tempering is micro-cutting wear in association with plastic deformation wear.

  5. Comportamiento del hierro nodular austemperizado en condiciones de corrosión y desgaste // Behavior of austempered ductile iron under wear and corrosion conditions

    Directory of Open Access Journals (Sweden)

    L. Goyos Pérez

    1999-07-01

    Full Text Available Los hierros nodulares en general y los austemperizados en particular han sido usados con cada vez mayor frecuencia debido asus relevantes propiedades mecánicas en comparación con su costo.En el presente trabajo se valora el comportamiento del hierro nodular ante el trabajo en condiciones de desgaste y corrosión,luego de ser sometido a diferentes tratamientos de austemperizado.Fueron usados un hierro nodular aleado con níquel y molibdeno y otro no aleado. Ambos hierros fueron sometidos a diferentestratamientos de austemperización con mantenimientos isotérmicos a temperaturas entre 250°C y 425°C por tiempos entre 15 y180 minutos.Las muestras tratadas fueron sometidas a ensayos de desgaste por fricción en condiciones no lubricadas determinando laspendientes de desgaste uniforme para cada caso. La resistencia a la corrosión fue determinada mediante el métodopotenciométrico usando como medio el jugo de caña sintético.A partir de los resultados obtenidos se valora la influencia de los diferentes tratamientos sobre las propiedades estudiadas y sedeterminan los más efectivos desde el punto de vista técnico económico.Palabras claves: Hierro nodular, corrosión, desgaste, austemperizado.____________________________________________________________________________AbstractNodular irons and particularly austempered ductile iron has been used more and more due to their excellent mechanicalproperties in comparison with their cost.Presently work deals on behavior of nodular iron working under wear and corrosion conditions, after being submitted todifferent austempered treatments.A nodular iron alloyed with nickel and molybdenum were used as well as a not alloyed one. Both irons were treated underdifferent austempered treatment combinations using isothermal maintenance to temperatures between 250°C and 425°C andspending times between 15 and 180 minutes.Samples were submitted to non-lubricated wear using a “pin on disk” method evaluating the

  6. Study of the influence of Cu and Ni on the kinetics of strain-induced martensite in austempered ductile cast iron; Estudio de la influencia del Cu y Ni en la cinetica de transformacion martensitica inducida por deformacion en fundiciones nodulares austemperadas

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, D.; Navea, L.; Garin, J.; Aguilar, C.; Guzman, A.

    2013-09-01

    The objective of this work was to study the influence of copper and nickel on the kinetics of strain-induced martensite in austempered ductile cast iron. The austempered ductile cast irons were obtained from two ductile cast irons with different copper and nickel contents by means of austempering treatment. The deformation was carried out using a rolling mill. The quantification of the phases was obtained by means of X ray diffraction, while the microstructural characterization was carried out using optical and scanning electron microscopy. It was proved that the kinetics of strain-induced martensite in austempered ductile cast iron can be modeled using the equations proposed by Olson- Cohen and Chang et al. Based on the results obtained from these analyses, it is possible to conclude that the nickel and copper complicate the martensite transformation because these elements increase the staking fault energy of the austenite and its thermodynamic stability. (Author)

  7. Isothermal Quenching Temperature and Time on Microstructure and Mechanical Properties Effect of Austempered Ductile Iron%等温淬火温度和时间对奥贝球铁组织性能的影响

    Institute of Scientific and Technical Information of China (English)

    吴秋敏; 袁延彬; 李广路

    2012-01-01

    本文通过工艺试验,介绍了奥贝球铁在等温淬火的不同温度下的变化情况及对其切削性能的影响。给出了最佳等温淬火温度和时间。%This article, through process test. introduced changing conditions and its cutting performance of austempered ductile iron in the isothermal quenching ureter different temperatures, giving the optimal austempering temperature and time.

  8. The bainite transformation and the carbide precipitation of 4.88% aluminium austempered ductile iron investigated using electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kiani-Rashid, A.R. [Department of Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 91775-1111, Mashhad (Iran, Islamic Republic of)], E-mail: fkiana@yahoo.com

    2009-04-17

    The transformation to a bainitic microstructure during austempering under different conditions was examined for the most successful of the experimental casts. Austenitising temperature of 920 deg. C and austempering temperature of 350 deg. C for different holding times have been used. Microstructures have been examined by SEM and transmission electron microscopy (TEM). It was found that isothermal transformation at 350 deg. C for different soaking times gave a typical bainitic microstructure that increased with increasing austempering time. Extension of isothermal transformation time leads to precipitation of carbides which also depended on the bainitic phase transformation.

  9. Recent development of ductile cast iron production technology in China

    OpenAIRE

    Cai Qizhou; Wei Bokang

    2008-01-01

    Recent progress in the production and technology of ductile cast iron castings in China is reviewed. The manufacture and process control of as-cast ductile iron are discussed. The microstructure, properties and application of partial austenitization normalizing ductile iron and austempered ductile iron (ADI) are briefl y depicted. The new development of ductile iron production techniques, such as cored-wire injection (wire-feeding nodularization) process, tundish cover ladle nodularizing proc...

  10. Estudio experimental sobre el comportamiento del hierro austemperado nitrurado (adi a la fatiga de contacto. // Experimental study to contact fatigue behavior of nitrided-austempered ductile iron.

    Directory of Open Access Journals (Sweden)

    C. Figueroa

    2001-10-01

    Full Text Available En el presente trabajo se muestra un estudio sobre el hierro fundido austemperado nitrurado sometido a pruebas de fatiga decontacto. El mismo se austenitizó y austemperó a las temperaturas de 900 y 3800C respectivamente, seleccionándose enambos casos un tiempo de 2 horas. Después se le aplicó un proceso de nitruración gaseosa a 5700C durante 6 horas.Las experiencias fueron realizadas en una máquina para el ensayo de fatiga de contacto con discos. Las presionesHertzianas utilizadas fueron de 1.73, 1.78, 2.04, 2.41, 2.46 y 2.71 GPa.La composición de fases se determinó utilizando la difracción de rayos X, evidenciándose la presencia de los compuestos e(Fe2-3N y g¢ (Fe4N. Los defectos tales como: pittings spalls y grietas fueron observados por medio de la microscopíaelectrónica de barrido (SEM. Los resultados indicaron que la capa nitrurada entre 5 y 6 micras de espesor desaparece bajola acción de las presiones de contacto. Por otra parte se pudo detectar una disminución de la resistencia a la fatiga en el ADInitrurado cuando fueron utilizadas bajas presiones Hertzianas También se comprobó que los nódulos de grafito actúancomo barreras a la propagación de grietas.Palabras claves: Fatiga de contacto, Capa nitrurada, hierro dúctil austemperado, máquina de fatiga condiscos, rayos X._____________________________________________________________________AbstractThis paper presents a study on the behavior of nitrided austempered ductile iron (ADI under contact fatigue tests. ADI wasaustenitized at 9000C for 2 hours and austempered at 380oC for 2 hours. Later, the ADI was nitrided at 570oC for a periodof 6 hours.The contact fatigue tests were carried out using a disc test machine. Hertzian pressures of 1.73, 1.78, 2.04, 2.41, 2.46 and2.71 were used during the tests.The phase composition of nitride layer was determined using X-ray analysis, which detected the presence of the e and g¢phases. The pitting, spalls and cracks that appeared

  11. Caracterización de la capa de boruros formada durante la austenización de un hierro nodular austemperizado//Characterization of borides coating formed during austenitization of an austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Urbano Ordóñez‐Hernández

    2015-01-01

    Full Text Available En este trabajo se ha investigado el efecto de la austenitización y el borurado simultáneos, a 950 ºC, en la microestructura, la microdureza Vickers y el espesor de la capa borurada en medio líquido de un hierro nodular austemperizado no aleado. Se demostró que es posible obtener una capa de boruros de hierro muy bien estructurada con la microdureza Vickers suficientemente alta (1400 HVy con adecuado espesor de capa de 67 μm, sobre un sustrato de ausferrita típico de las fundiciones nodulares austemperizadas. Por medio de un ensayo pin on disc modificado, se comprobó la superior resistencia al desgaste abrasivo de la capa de boruros depositada durante la austenización del ADI, comparada con la máxima obtenida durante el austempering de éste sin aplicar el recubrimiento.Palabras claves: hierro nodular, borurado, austenización, austemperizado.______________________________________________________________________________AbstractThe effect of simultaneous austenitization and boriding at 950 ºC, on microstructure, Vickers hardness and boronized layer thickness of a non alloyed austempered ductile iron has been investigated. It was demonstrated that it is possible to obtain a well formed boronized layer with a Vicker hardness sufficiently high (1400 HV, and with an appropriated 67μm layer thickness, on a typical ausferrite ADI substrate. By using a modified pin on disc test, it was demonstrated the higher abrasion wear resistance of borides layer deposited during ADI austenitization process, compared with Vickers hardness of low temperature noncoated austempered ductile iron.Key words: ductile iron, boriding, austenitization, austempering.

  12. Characterisation of austempered spheroidal graphite aluminium cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Boutorabi, S.M.A. [Iran Univ. of Science and Technology, Tehran (Iran, Islamic Republic of). Dept. of Metallurgy and Materials

    1997-06-01

    The micro constituents of austempered spheroidal graphite aluminium cast iron were investigated. The heat tinting, special etching and microhardness measurement techniques were used. The results showed that the colour of each micro constituents and the hardness values in austempered ductile iron depend on the carbon content of each phase. The above techniques were supported by using an special etching which showed similar differences in each phase. It was shown that the heat tinting and special etching are reliable tools to characterise the complex matrix of ADI. The microhardness data supported interestingly the colour changes in above technique. (orig.)

  13. Research of Austempered ductile Iron Gears in Diesel Engine%奥贝球铁齿轮在柴油机上的应用研究

    Institute of Scientific and Technical Information of China (English)

    刘海霞; 傅明喜; 孙少纯; 司乃潮; 杨永涛; 陈柏林; 钱鲁阳

    2001-01-01

    The influences of different austemper temperatures,content of manganese,silicon,copper and molybdenum on the microstructures and mechanical properties of austempered ductile iron (ADI) were studied.The effects of work hardening on machinablities of ADI were also discussed.Meanwhile some ADI gears replaced the 40Cr hardened and tempered steel gears in a diesel engine to test their functions of reducing noise and wear resistance.It was found that the mechanical properties of ADI gears were higher than that of 40Cr hardened and tempered steel gears.The ADI gears decreased the working noise of the whole diesel engine by 1.92dB and the noise in side of the gears by 5.3dB.After 45 hours' run-in and 200 hours' continuous operation in demarcated conditions,there was no abnormal wear in the ADI gears and there still existed allowance of 0.13mm between limit gap and gear gap.So the frictional wear properties of ADI gears were qualified and the ADI gears produced could meet the design and appilication requirements.%研究了不同等温温度及Mn、Si、Cu、Mo对奥贝球铁组织和力学性能的影响,讨论了奥贝球铁加工硬化对机加工性能的影响。同时,将奥贝球铁齿轮代替40Cr调质钢齿轮进行装机试验,对降噪声和耐磨性进行了测试。结果表明,奥贝球铁齿轮与40Cr调质钢齿轮相比,力学性能高,柴油机整机噪声下降1.92dB,齿轮侧噪声下降5.3dB。奥贝球铁齿轮经过45h磨合后,在标定工况下连续运转200h,齿轮无异常磨损,齿轮间隙离极限间隙还有0.13mm的余量,所以其摩擦磨损性能合格,所生产的奥贝球铁齿轮满足设计使用要求。

  14. Application of successive austempering process to spheroidal graphite cast iron produced by inmold process. Inmold ho de seizoshita kyujo kokuen chutetsu eno chikuji austemper ho no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Oide, T.; Ahmadabadi, M.; Kawashima, S. (Tohoku University, Sendai (Japan). Faculty of Engineering)

    1994-06-25

    Application of successive austempering process to the iron produced by inmold process leads to much higher graphite nodule count in the structure than the other spheroidizing methods. In this study, to improve the toughness of spheroidal graphite cast iron produced by inmold process, successive austempering process was applied to austemper ductile iron (ADI) production. Both hardenability and austemperability of the iron could be controlled with Mn alloying through the two-stage austempering at high and low temperatures. Higher retained austenite volume fraction and lower untransformed austenite volume fraction were obtained in the most suitable duplex upper and lower bainitic structure. It was confirmed that the impact energy of ADI treated by successive austempering process was remarkably much higher than the conventional austempering processes. In this process, an excellent value of toughness was obtained by selecting a combination of holding temperature and holding time, strictly. 17 refs., 10 figs., 2 tabs.

  15. Rolling Wear and Damage Properties of Austempered Ductile Iron%等温淬火球墨铸铁滚动磨损与损伤性能

    Institute of Scientific and Technical Information of China (English)

    付志凯; 王文健; 丁昊昊; 顾凯凯; 刘启跃

    2015-01-01

    利用不同热处理方式和球化工艺,获得两种显微组织和不同硬度的等温淬火球墨铸铁(Austempered Ductile Iron,ADI)材料,利用MMS-2A微机控制摩擦磨损试验机对比研究了两种等温淬火球墨铸铁材料、车轮材料与U71Mn钢轨匹配时的滚动磨损与损伤性能.结果表明:ADI材料与U71Mn钢轨匹配时的摩擦因数明显小于车轮材料;由于ADI材料具有自润滑效果导致其磨损率明显小于车轮材料,ADI材料的自润滑性能也降低了对摩副U71Mn钢轨的磨损率,其中含有较大球状石墨和较少残余奥氏体的ADI2材料和对摩副U71Mn钢轨的磨损率最小;ADI材料的磨损机制主要表现为轻微疲劳磨损,对摩副U71Mn钢轨的磨损机制主要表现为黏着和轻微疲劳磨损,而轮轨材料匹配时的塑性流动层显著,损伤以表面疲劳裂纹和剥层损伤为主.

  16. The studies of nodular graphite cast iron early stages austempering

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2008-12-01

    Full Text Available The results of early stage of ductile cast iron austempering are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with enriched with Cu EN-GJS-500-7 grade ductile iron. The specimens were first solution heat treated 1 hour in 910oC and then isothermally quenched for different time in molten tin at the temperature 275oC. The mechanical properties of as cast and heat treated specimens were tested to evaluate tensile Rm and yield strength R p, 0.2 and elongation A5. Additionally hardness measurements were carried out using Brinell-Rockwell method. Structure of the specimens both as cast and after austempering was studied using conventional light microscopy. Moreover, scanning electron microscopy (SEM was applied for fracture surface observations. It was concluded that short time low temperature austempering lead to formation martensitic microstructure characterized by very high hardness with almost zero ductility. The lack of ductility make the material very sensitive to any structure defects which work as a stress concentrators which strongly influence the strength of heat treated ductile iron specimens.

  17. Recent development of ductile cast iron production technology in China

    Directory of Open Access Journals (Sweden)

    Cai Qizhou

    2008-05-01

    Full Text Available Recent progress in the production and technology of ductile cast iron castings in China is reviewed. The manufacture and process control of as-cast ductile iron are discussed. The microstructure, properties and application of partial austenitization normalizing ductile iron and austempered ductile iron (ADI are briefl y depicted. The new development of ductile iron production techniques, such as cored-wire injection (wire-feeding nodularization process, tundish cover ladle nodularizing process, horizontal continuous casting, and EPC process (lost foam for ductile iron castings, etc., are summarized.

  18. Effects of silicon content and austempering condition on the impact characteristics of austempered ductile cast iron. Kyojin kyujo kokuen chutetsu no jinsei ni oyobosu osutenpa shori joken to Si ryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, M. (Daido Inst. of Technology, Nagoya (Japan)); Kobayashi, T. (Toyohashi Univ. of Technology, Aichi (Japan)); Matsuo, K. (Kurimoto Iron Works, Ltd., Osaka (Japan))

    1990-07-25

    Austempered spherical graphite cast iron (ADI) is extensively expeted as a mechanical structural material because of high tenacity and resilience as well as fatigue strength and wear resistance. These excellent properties are attributed to the abundantly remaining austenite because the formation of carbides is restricted by the action of the silicon element. It is, therefore, important for obtaining the strong cast iron material to control the amount of the retained austenite. In this study, the impact characteristics was investigated for acquiring the basic materials concerning the influence of the temperature, time of austempering and the amount of silicon. The added amount of silicon is most suitably 2.1%. Samples without Mn and Ni showed an impact value of about 2 times of the amount added. At 400 {degree} C, however, the impact value reduced to half by the growth of coarse ferrite and bentonite. Time of austempering was 1 hour and showed a stable impact value and load of breaking. Transition temperature shifted tolow side by the increase of amount of silicon. 14 refs., 10 figs., 1 tab.

  19. 奥-贝球铁断裂与疲劳研究的新近进展%Progress of Research on the Fracture and Fatigue of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    戴品强; 何则荣; 毛志远

    2000-01-01

    奥-贝球铁具有很强的强度、塑性、韧性、疲劳强度和耐磨性等综合性能,应用日益广泛,已成为一种重要的工程材料。近年来对其断裂与疲劳的研究发展很快,得到不断的深入,本文详细介绍了其新近进展。%Austempered ductile irons (ADI) exhibit excellent combination of strength, ductility,toughness, fatigue strength and wear resistance. They have been successfully used in many fields and become an important engineering material. The fracture and fatigue of ADI have been investigated extensively in the recent years. The recent developments on the mechanisms of fracture and fatigue in ADI are reviewed in this paper.

  20. The studies of nodular graphite cast iron early stages austempering

    OpenAIRE

    A. Krzyńska; M. Kaczorowski

    2008-01-01

    The results of early stage of ductile cast iron austempering are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with enriched with Cu EN-GJS-500-7 grade ductile iron. The specimens were first solution heat treated 1 hour in 910oC and then isothermally quenched for different time in molten tin at the temperature 275oC. The mechanical properties of as cast ...

  1. Effect of austempering temperature and time on the kinetics and microstructure of austempered compacted graphite cast irons; Einfluss von Zwischenstufenverguetungstemperatur und -zeit auf die Kinetik und die Mikrostruktur von zwischenstufenverguetetem, Gusseisen mit Vermiculargraphit

    Energy Technology Data Exchange (ETDEWEB)

    Teymourian, Mehdi [LMI Co., Tehran (Iran, Islamic Republic of). Casting Dept.; Boutorabi, Seyed Mohammad Ali [Iran Univ. of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of). Center of Excellence for Advanced Materials

    2012-07-01

    After starting the austempering nucleation of bainitic ferrite was observed within a very short time. Samples that austempered for 2 min. showed martensite in the microstructure. By increasing the austempering time from 30 min to 90 min the retained austenite decomposes and X-ray diffraction observations revealed the greatest volume fraction of retained austenite up to 17.3 and 23.8 percent when austempered for 30 min. Micro-hardness of the bainitic Verbesferrite increased up to 370 and 500 HV and micro-hardness of the retained austenite increased up to 300 and 400 HV at the austempering temperatures of 300 C and 400 C respectively. In comparison to austempered ductile iron, the austempered compacted graphite cast iron shows higher rate of bainitic reaction. Bainite formation driving force and consequently the rate of austempering process are higher in compacted graphite cast irons. (orig.)

  2. Effect of graphite nodule count and Mn content on successive austempering process of austempered ductile iron; ADI no chikuji austemper ho ni oyobosu kokuen tsubusu to Mn ryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Oide, T.; Ahmadabadi, M.; Saito, M. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-02-25

    Shock test was executed for a test piece where the combination of a wide range of austempering conditions was selected and the effective graphite nodule count in the successive austempering process method, the range of Mn amount, etc. were discussed. The low and high graphite nodule counts of sample were 82 - 114 and 229 - 364 piece/mm{sup 2}, respectively. The low and high Mn were 0.26 - 0.65 % and 0.96 - 1.05 %, respectively. The heat treatment cycle was retained to be 1173K, 648K, and 588K in argon gas atmosphere. The Sharpy shock test and organization observation were performed for each test piece, thus revealing that a higher toughness value than that obtained by normal treatment could be obtained by the HLAT method; the better the graphite nodulation count was, the higher the toughness was; it was effective that the Mn was approximately 0.6 %; the influence given to the shock energy value was extremely larger by residual austenite volume than the untransformed austenite module. 7 refs., 12 figs., 2 tabs.

  3. 水附着状态下奥贝球铁的拉伸性能及断裂机制%The Tensile Properties of Austempered Ductile Iron in Condition of Contact with Water and its Fracture Mechanism

    Institute of Scientific and Technical Information of China (English)

    蔡启舟; 魏伯康; 林汉同; 田中雄一

    2001-01-01

    The tensile properties of austempered ductile iron (ADI) were tested in condition of contact with water and its fracture mechanism was investigated in this paper. Both tensile strength and elongation of the iron were decreased drastically, it exhibited remarkable water-embrittlement in condition of contact with water. Especially, ADI austempered specimens of the iron in process window showed more remarkable embrittlement than others. White spot region regarded as fracture initiation point was observed on fracture surface tested in contact with water. From this result, it was suggested that embrittlement behavior of ADI resulted from a local embrittlement near the surface of specimen during plastic deformation and it led to a rapid fracture of the entire specimen.%研究结果表明,水附着状态下,奥贝球铁的抗拉强度和伸长率显著降低,发生明显的脆化现象,特别是在工艺窗口内等温淬火处理的试样脆化更显著。经断口分析发现,这种脆化现象是水附着拉伸试样在塑性变形初期,表面附近产生了脆性断裂区域,作为试样破坏的起点,导致试样早期断裂而造成的。

  4. Effects of austempered temperature on corrosive wear behavior of carbidic austempered ductile iron%淬火温度对含碳化物等温淬火球墨铸铁耐腐蚀磨损性能的影响

    Institute of Scientific and Technical Information of China (English)

    李国禄; 董天顺; 刘金海; 张建军

    2014-01-01

    In order to study the effects of austempered temperature on corrosive wear behaviors of carbidic austempered ductile iron (CADI), the CADI was prepared, and the wear corrosion resistance test was conducted in acid medium, neutral medium and alkaline medium, respectively. The results show that in acid medium and alkaline medium, the mass loss of CADI first increased and then decreased with increasing austempered temperature. But in neutral medium, the mass loss of CADI increased gradually with increasing austempered temperature. The performance of corrosion wear resistance of CADI in acid medium is inferior to that in alkaline medium and neutral medium. While the performance of corrosion wear resistance of CADI is obviously superior to that of low chromium white cast iron under different pH values medium. Therefore, CADI is a material with good property of corrosion wear resistance.%通过等温淬火获得含碳化物等温淬火球墨铸铁(carbidic austempered ductile iron,简称CADI),并分别在中性、酸性和碱性腐蚀介质中进行腐蚀磨损实验,研究淬火温度对CADI在不同腐蚀介质中耐腐蚀磨损特性的影响,并与低铬铸铁进行对比。结果表明:在酸性和碱性介质中,CADI 的质量磨损随等温淬火温度升高先增加,然后再减少;在中性介质中,CADI 的质量磨损随等温淬火温度升高而逐渐增加;CADI 在酸性介质中的耐腐蚀磨损性能相对较差;CADI在不同pH值溶液中的耐磨损性能均优于低铬铸铁,是一种优良的耐腐蚀磨损材料。

  5. Recent development of ductile cast iron production technology in China

    Institute of Scientific and Technical Information of China (English)

    Cai Qizhou; Wei Bokang

    2008-01-01

    Recent progress in the production and technology of ductile cast iron castings in China is reviewed.The manufacture and process control of as-cast ductile iron are discussed.The microstructure.properties and application of partial austenitization normalizing ductile iron and austempered duclile iron(ADI)are briefly depicted.The new development of duclile iron production techniques,such as cored-wire injection(wire-feeding nodularization)process,tundish cover ladle nodularizing process,horizontal continuous casting,and EPC process (lost foam)for ductile iron castings,etc.,are summarized.

  6. Effects of Graphite Form and Amount on Performance of Austempered Ductile Iron%石墨形态和数量对奥-贝球铁性能的影响

    Institute of Scientific and Technical Information of China (English)

    许太平; 徐伟; 蔡彦强; 贾连杰

    2013-01-01

    For the austempered ductile iron as required by tensile strength ≥1200MPa, elongation after fracture≥1% and energy absorption (sample without notch)≥35J, if its spheroidization rate is lower than level 3, the spheroidal graphite is thicker than level 6 and its amount per mm2 is less than 180, its mechanical performance after isothermal treatment will be difficult to suit the specification requirements.%对于要求抗拉强度≥1200MPa;断后伸长率逸1%;吸收能量(无缺口试样)≥35J的奥-贝球铁,如果其球化率差于3级,球墨粗于6级且每平方毫米球墨少于180个,等温处理后的力学性能不易达到规范要求。

  7. Wear resistance studies of an austempered ductile iron with the aid of a single pass grooving pendulum; Estudo do comportamento em desgate de um ferro fundido nodular austemperado atraves da tecnica da tecnica de esclerometria pendular

    Energy Technology Data Exchange (ETDEWEB)

    Velez, J.M.; Tschiptschin, A.P. [Sao Paulo Univ., SP (Brazil). Escola Politecnica

    1995-12-31

    The abrasive wear resistance of an austempered ductile iron was studied with the aid of a single pass grooving pendulum. Specimens were austenitized at 860 deg C and austempered at 370 deg C for 30, 60, 90, 180 and 240 min. Austenite transformation kinetics was measured by quantitative metallography. Specimens for pendulum tests were gridded as squared based prisms (50 mm x 10 mm x 10 mm) and one of the faces submitted to metallographic polishing before the test. A hard metal cutting tool was used as abrasive. The absorbed energy as well as the loss of matter were measured. Scanning Electron Microscopy was used to analyze the surface topography of the scratched specimen. It was observed a maximum in the absorbed specific energy for the specimen treated for 60 min. with a microstructure of bainite ferrite plus plus 42% volume fraction of retained austenite. All other structures (ferrite plus carbides, ferrite plus lower contents of austenite and martensite plus austenite) gave lower values of absorbed specific energy. Observation of scratches and chips formed on the surface of the specimen can explain the above mentioned behaviour 12 refs., 11 figs., 2 tabs.

  8. 等温淬火球铁热处理工艺参数的优化方法%Optimization Method of Heat Treatment Parameters for Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    王洪; 郭旭红; 王伟

    2011-01-01

    等温淬火球铁(ADI)作为性能可设计材料,其热处理工艺参数的优化设计是开发性能优良的ADI材料的关键.在不改变热处理生产条件的基础上,采用不同的等温淬火温度和时间,分别制作出不同力学性能检测数据的各种试样,并将实验数据用于建立热处理工艺参数与力学性能的模糊减法聚类函数模型.以抗拉强度、冲击韧度、硬度等力学性能为用户需求目标,等温淬火温度和时间为可设计变量,采用NSGA Ⅱ遗传算法作为优化算法进行优化计算.结果表明:用这种方法设计满足ASTM3,ASTM4级力学性能要求的热处理参数,可以得到最佳的等温淬火预测温度和时间分别为333℃,136 min和312℃,132 min.%Austempered ductile iron (ADI) is a performance designable material. The optimization design of its heat treatment parameters is the key to develop a good performance ADI material. The fuzzy subtractive clustering function model about the heat treatment parameter and mechanical properties was built using experiment data on the base of no changing the production conditions of heat treatment, various ADI samples with test data of different mechanical properties were made at the different austempering temperatures and time. The heat treatment parameters were chosen by taking tensile strength, impact toughness and hardness as objective of eustomers demand, taking austempering temperature and time as designable variables, and using the NSAG Ⅱ genetic algorithm as optimization algorithm. The results show that this method can satisfy the parameters of heat treatment required by mechanical properties ASTM grade 3 and 4, and can get the best prediction austempering temperature and time ,which are respectively 333 ℃ ,136 min and 312 ℃ ,132 min.

  9. Effect of Shot Peening Process on Fatigue Behavior of Alloyed Austempered Ductile Iron%喷丸强化对合金化奥贝球铁疲劳性能的影响

    Institute of Scientific and Technical Information of China (English)

    Amir Sadighzadeh Benam; Sasan Yazdani; Behzad Avishan

    2012-01-01

    喷丸处理是改进金属工件疲劳性能最常规的表面处理方法.文中研究了喷丸处理对合金化奥贝球铁(ADI)疲劳性能的影响.等温淬火包括875℃保温90 min奥氏体化处理,然后在320℃、365℃和400℃进行等温处理.用直径0.4~0.6mm的丸喷丸后的试样做旋转弯曲疲劳试验.对试样进行XRD和SEM分析,测定显微硬度和粗糙度,研究试样的疲劳性能.结果表明,在320℃、365℃和400℃等温处理的试样喷丸后疲劳强度分别增加了27.3%、33.3%和48.4%.%Shot peening is one of the most common surface treatments to improve the fatigue behavior of metallic parts. In this study the effect of shot peening process on the fatigue behavior of an alloyed austempered ductile iron (ADI) has been studied. Austempering heat treatment consisted of austenitizing at 875℃ for 90 min and following austempering at 320 ℃, 365 ℃ and 400 ℃. Rotating-bending fatigue test was carried out on samples after shot peening by 0.4 to 0.6 mm shots. XRD and SEM analysis, micro hardness and roughness tests were carried out to study the fatigue behavior of the samples. Results indicate that the fatigue strengths of samples austempered at 320 ℃, 365 ℃ and 400 ℃ are increased by 27.3%, 33.3% and 48.4%, respectively after shot peening process.

  10. Cu和Mo对厚大断面等温淬火球墨铸铁件淬透性的影响%Influence of Cu and Mo on the Hardenability of Austempered Ductile Iron with Heavy Section

    Institute of Scientific and Technical Information of China (English)

    沈鹏; 曲迎东; 李荣德; 张新宁; 姜珂

    2013-01-01

    In order to improve the hardenability of austempered ductile iron with heavy section, the influence of Cu and Mo on casting' s hardenability was studied. Five groups of ductile iron specimens with 1% Ni and 150 mm thickness were prepared, of which addition amount of Cu and Mo changed. The hardenability and mechanical properties were observed and tested after austenitizing at 900 ℃ for 3 h and austemper at 385 ℃ for 1.5 h. The results shows that the hardenability of ductile iron dose not improve obviously when Mo is 0.25% and Cu increases from 0.05% to 0.75%, the mechanical properties are corresponding with that of pearlitic structure. But when Mo increases to 0.36% and Cu is 0.75%, no pearlitic structure appears at the edge of dultile iron as well as only 5% pearlitic structure is found and others are coarser ausferrite structure in the core. Its mechanical properties meet the grade 4 of the European Community ADI standard. A small amount of Mo should be added instead of a large amount of Cu when ductile iron casting with heavy section is austempered.%为提高厚大断面等温淬火球墨铸铁(ADD件的淬透性,研究了Cu和Mo对铸件淬透性的影响.制备了5组壁厚为150 mm的球墨铸铁试样,5组试样中Ni元素控制在1%,改变Cu和Mo的添加量;经过900℃奥氏体化3 h+385℃等温淬火处理1.5h,对试样的淬透性及力学性能进行了观察和测试.结果表明:当Mo为0.25%,Cu由0.05%提高到0.75%时,铸件的淬透性没有明显改善,其力学性能偏向于珠光体的力学性能;当Mo提高到0.36%,Cu为0.75%时,铸件的淬透性有了明显的提高,边部没有珠光体析出,心部只存在5%左有的珠光体,其余为较粗的奥铁体组织,同时力学性能也达到了欧洲ADI四级标准.对厚大断面球墨铸铁件进行等温淬火处理时,应首先选择增加少量的Mo元素,而不是增加大量的Cu元素.

  11. Influencia de los factores microestructurales en la resistencia al desgaste por deslizamiento de las fundiciones nodulares austemperadas. // Influence of the microstructure factors in the sliding wear resistance of austempered cast ductile iron.

    Directory of Open Access Journals (Sweden)

    C. J. Diez Cicero

    2008-09-01

    Full Text Available Entre los materiales metálicos de mayor demanda, el hierro dúctil con grafito esferoidal o nodular ocupa en la actualidaduno de los lugares más importantes entre los hierros fundidos de alta resistencia. Desde hace unos veinticinco años laintroducción del hierro nodular austemperado significó de hecho una revolución en el campo de las aleaciones ferrosas. Enel presente trabajo se realiza un estudio de la influencia del conteo de nódulos de grafito del hierro nodular en el proceso deaustemperado, a partir de las características de las estructuras obtenidas, por la variación de la cantidad de nódulos degrafito y de las variables de tratamiento térmico. Dichas estructuras son sometidas a la acción del desgaste, en este caso aun desgaste por deslizamiento mediante un ensayo típico disco-zapata. Con los resultados obtenidos, se realiza un análisisestadístico de la influencia del conteo de nódulos en dichas propiedades y de las causas de este comportamiento, tomandoen consideración la interrelación del conteo de nódulos con las variables de tratamiento térmico utilizadas en las muestrasensayadas y su incidencia en el mecanismo de desgaste.Palabras claves: Hierro nodular, conteo de nódulos, austemperado, desgaste por deslizamiento.____________________________________________________________________________Abstract:A study about the influence of the graphite nodules quantity and some heat treatment parameters in the characteristic of castductile iron is presented. Experimental investigation of wear resistance by sliding is applied to specimens tested ofaustempered ductile irons using a test machine based in the disc- plate system. Statistical analysis about the influence of thegraphite nodule quantity in the wear resistance properties, so as well as, the causes of this behaviour taking into account thegraphite nodule count and some heat treatment variables is done.Key words: austempered ductile iron, graphite nodules, wear

  12. 等温淬火球墨铸铁在汽车底盘悬架类零件上的应用%Application of Austempered Ductile Iron to Automobile Suspension Components

    Institute of Scientific and Technical Information of China (English)

    曾圣湖; 黄建成; 武炳焕

    2011-01-01

    Lightweight upper chassis frame suspension part was designed, using austempered ductile iron (ADI) casting instead of steel casting. By strictly controlling the raw material and foundry and heat treatment processes, the mechanical property of the casting satisfies the specifications of ASTM A897/A897M-06 grade 1050-750-7, and the pilot production was realized. The trial production and test result indicate that the properties of casting meet the designed requirement, while the weight of the casting was reduced by 39.6%. After further improvement, the amount of ADI castings was increased, and the weight of all ADI castings in an automotive reached 550.4 kg.%对某车型上底盘悬架类零件进行轻量化设计,由铸钢件改用等温淬火球墨铸铁件.通过对原材料、铸造和热处理等工艺过程的严格控制,力学性能稳定达到了ASTM A897/A897M-06 Grade 1050-750-7要求,并实现了小批量生产.从试制及装车路试情况来看,满足了所设计的性能要求,零件重量减少了39.6%,并在后续改进中,进一步增加等温淬火球墨铸铁件数量,整车的等温淬火球墨铸铁件重量达到了550.4 kg.

  13. Statistical fatigue properties of ductile cast irons; Kyujo kokuen chutetsu no hiro kyodo no tokeiteki seishitsu

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, N.; Nishikawa, Y.; Inaba, K. [Gifu University, Gifu (Japan). Faculty of Engineering; Fukuyama, K. [Gifu Prefectural Police Headquarters, Gifu (Japan)

    1995-09-15

    Rotating bending fatigue tests of smooth specimens were carried out at room temperature on a pearlitic ductile cast iron (PDI) and austempered ductile cast iron (ADI). No significant difference due to sampling position from cast blocks in both materials was found in fatigue limit and fatigue life distribution. Then, the statistical fatigue properties of ferritic (FDI), ferritic/pearlitic (FPDI), pearlitic and austempered ductile cast irons were investigated. The fatigue life distributions of all ductile irons were well represented by the three parameter Weibull distribution modified by the saturated probability of failure. The shape parameters of FDI, FPDI and PDI were in proportion to {sigma}/{sigma}w independent on micro structure, while the shape parameters of both stress levels in ADI were smaller than unity. The fatigue strength of ADI was highest, but the scatter of fatigue life was largest among the all cast irons. 13 refs., 15 figs., 7 tabs.

  14. Improvement of static strength and fatigue crack propagation resistance in ductile cast iron by austempering from (. alpha. +. gamma. ) phase region. Bubun austenpering shori ni yoru kyujo kokuen chutetsu no seiteki kyodo to hiro kiretsu shinten teiko no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Y.; Asami, K.; Matsuoka, S. (Musashi Institute of Technology, Tokyo (Japan))

    1991-06-15

    The spheroidal graphite cast iron is better characterized in resistivity against the abrasion and heat, and economical efficiency than the normal carbon steel. Notice being taken of treatment temperature (800 to 840 centigrade) in the ({alpha}+{gamma}) phase region for the partial austempering treatment condition, able to improve the spheroidal graphite cast iron simultaneously in both statical tensile characteristics and fatigue crack propagation resistance, the present report compared dual phase as-cast material, single phase ferrite and single phase bainite. As a result, the morphological ratio of bainite becomes about 20% to the base morphology at 800 centigrade in treatment temperature. Then with progressively heightening to 815, 830 and 840 centigrade in it, the above ratio so heightens to about 40, 80 and 90%, respectively. The fatigue crack propagation resistance in the low DeltaK (low stress intensity factor) region is heightened by the partial austempering treatment to higher than that of dual phase as-cast material, single phase ferrite and single phase bainite, and most done at 800 centigrade in temperature where the bainite becomes about 20% in morphological ratio. 830 centigrade where the bainite becomes about 80% is judged to be the most appropriate treatment temperature for both the statical tensile characteristics and fatigue crack propagation resistance. 3 refs., 16 figs., 3 tabs.

  15. Efecto del conteo de nódulos en la resistencia a la tracción de los hierros dúctiles austemperados. // Effect of nodules count in the tensile strength of austempered ductile irons.

    Directory of Open Access Journals (Sweden)

    C. J. Diez Cicero

    2004-01-01

    Full Text Available Entre los materiales metálicos de mayor demanda, la producción de hierro con grafito nódular ocupa uno de los lugaresmás importantes entre los hierros fundidos de alta resistencia y con la introducción del tratamiento térmico deaustemperado, aplicado a estas fundiciones, se da lugar a una nueva familia de materiales, caracterizados por su altaresistencia mecánica y elevada tenacidad, que mantienen la economía y facilidad de producción de las fundicionesnodulares.Este trabajo, hace una valoración del comportamiento de hierros nodulares, con diferentes conteos de nódulos, a los que lesfue aplicado el tratamiento de austemperado y posteriormente se les sometió a ensayos de propiedades mecánicas detracción.Con los resultados obtenidos, se hace un análisis de la influencia del conteo de nódulos en dichas propiedades, así comotambién, de la interrelación del conteo de nódulos con las variables de tratamiento térmico utilizadas en las muestrasensayadas.Palabras claves: Hierro nódular, conteo de nódulos, austemperado.____________________________________________________________________________Abstract.At the present, iron production with nodular graphite, occupies one of the most important places in the production ofmetallic materials high resistance. The introduction of the austempered heat treatment, gives rise to a new family ofmaterials, characterized by its high mechanical resistance and elevated tenacity, this family maintain the economy andfacility of production of the smeltings nodules. This work, makes a valuation of the nodules iron behavior, with differentnumber of nodules, to which the austempered treatment was applied, in order to test mechanical properties. With theobtained results, an analysis is carriewd out to control the influence of the count of nodules in these properties, as well as,the interrelation of the count of nodules with the used heat treatment variables in the samples.Key words: nódular Iron, count of

  16. Intercritical heat treatments in ductile iron and steel

    Science.gov (United States)

    Aristizabal, Ricardo E.

    Materials such as dual phase (DP) steels, transformation induced plasticity (TRIP) steels and dual phase ductile irons are produced by intercritical heat treatments. These materials can provide significant weight savings in the automotive industry. The goal of this dissertation is to study intercritical heat treatments in ductile iron and steel to optimize the production parameters. Three different aspects were addressed. First, common steels were intercritically austenitized and austempered (intercritically austempered) under a variety conditions. The results showed that common grade steels that were intercritically austempered exhibited tensile properties in the same range as DP and TRIP steels. The second study consisted of determining the effect of heat treatment conditions on the tensile properties of intercritically austenitized, quenched and tempered ductile iron (IAQ&TDI). The results showed that (1) ultimate tensile strength (UTS) and yield strength (YS) were determined by the volume fraction of martensite, (2) tempering improved the elongation 1.7-2.5 times with only a slight decrease in strength, (3) the carbon in austenite formed during the intercritical heat treatment of ductile iron with a ferritic-pearlitic matrix came from the carbon available in the matrix and that carbon diffusion from the graphite nodules was restricted, and (4) limited segregation of substitutional elements occurred during intercritical austenitizing. Finally, intercritically austempered ductile iron (IADI) alloyed with different amounts of manganese and nickel was produced. Tensile properties and microstructure were determined. Also, the stability of the austenite during deformation and the lattice strains of the ferrite and the austenite phases were determined using x-ray diffraction (XRD) and neutron diffraction. The results indicated that: 1) high manganese concentrations produced materials with large blocky, low carbon austenite particles at the intercellular boundaries

  17. Electron microstructure and mechanical properties of silicon and aluminum ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Sidjanin, L. (Univ. of Novi Sad (Yugoslavia). Dept. of Production Engineering); Smallman, R.E.; Young, J.M. (Univ. of Birmingham (United Kingdom). School of Metallurgy and Materials)

    1994-09-01

    Samples of unalloyed silicon and aluminum spheroidal graphite cast iron have been studied in the austempered condition. Austempering times of up to 3 h at 400 C for Al SG and 1 h at 350 C for Si SG gives a typical ADI microstructure consisting of carbide-free bainitic ferrite and stable, high carbon enriched, retained austenite. This has an attractive combination of elongation and strength. For longer austempering times transition carbides are precipitated in the bainitic ferrite, [eta]-carbide in the upper bainitic range, i.e. 400 C for Al SG and 350 C for Si SG, and [epsilon]-carbide in the lower bainite range. Increasing amounts of transition carbide reduce the ductility and produce a mixed mode of fracture. For longer austempering times [chi]-carbide is precipitated at the ferrite/austenite boundaries leading to a more brittle fracture mode.

  18. Embrittlement of austempered nodular irons: Grain boundary phosphorus enrichment resulting from precipitate decomposition

    Science.gov (United States)

    Klug, R. C.; Hintz, M. B.; Rundman, K. B.

    1985-05-01

    The microstructures, mechanical properties, and fracture behavior were characterized for a series of Mg treated nodular cast iron specimens austenitized at 1170, 1255, and 1340 K and subsequently austempered at 640 K. The ductility and toughness of the alloy decreased as austenitization temperatures were increased, which is contrary to the behavior anticipated from the observed micro-structural evolution. Fractographic and surface chemical analyses demonstrated that the mechanical property degradation was associated with embrittlement of the austenite grain boundaries by phosphorus. The primary mechanism of grain boundary phosphorus enrichment does not appear to be equilibrium segregation, and an alternative mechanism based on the decomposition of P rich precipitates is proposed and discussed.

  19. Efecto del conteo de nódulos en la resistencia al desgaste por abrasión de los hierros dúctiles austemperados. // Effect of nodules count in the waste by abrasion resistance for ductile austempering irons.

    Directory of Open Access Journals (Sweden)

    C. J. Diez Cicero

    2004-05-01

    Full Text Available Entre los materiales metálicos de mayor demanda, la producción de hierro con grafito nodular, ocupa en la actualidad unode los lugares más importantes entre los hierros fundidos de alta resistencia, y con la introducción del tratamiento térmicode austemperado aplicado a estas fundiciones, se da lugar a una nueva familia de materiales, caracterizados por su altaresistencia mecánica y elevada tenacidad, que mantienen la economía y facilidad de producción de las fundicionesnodulares.Este trabajo, hace una valoración del comportamiento de hierros nodulares, con diferentes conteos de nódulos, a los que lesfue aplicado el tratamiento de austemperado y posteriormente se les sometió a ensayos de desgaste abrasivo.Con los resultados obtenidos se hace un análisis de la influencia del conteo de nódulos en dichas propiedades, así comotambién de la interrelación del conteo de nódulos con las variables de tratamiento térmico utilizadas en las muestrasensayadas.Palabras claves: Hierro nodular, conteo de nódulos, austemperado.____________________________________________________________________________Abstract.Between the metallic materials of greater demand, the iron production with nódular graphite occupies at the present time,one of the most important places between fused irons of high resistance, and with the introduction of the austempering heattreatment, applied to these meltings, brings a new family of materials, characterized by its high mechanical resistance andelevated tenacity, that maintain the economy and facility of production of the nodular smeltings.This work makes a valuation of the nodular irons behaviors, with different counts from nodules, to which the austemperingtreatment was applied, and later they were put under tests of abrasive wearing.Of the obtained results, takes control of the influence the nodules count in these properties, as well as, of the interrelation ofthe nodules count, with the used variables of heat

  20. Influence of the Mn content on the kinetics of austempering transformation in compacted graphite cast iron

    Science.gov (United States)

    Desimoni, J.; Mercader, R. C.; Laneri, K.; Gregorutti, R.; Sarutti, J. L.

    1999-11-01

    Mossbauer spectroscopy has been used to monitor the kinetics of austempering transformation in two compacted graphite (CG) cast irons alloyed with 0.11 and 0.58 wt pct of Mn, respectively. The phase relations were analyzed in terms of the Johnson-Mehl’s equation, determining the kinetics parameters n (time exponent) and k (constant rate of the transformation). The values obtained were n=1.4 and k=7.47 × 10-3 s-1 for the low-Mn alloy, and n=2.2 and k=3.9×10-3 s-1 for the high-Mn alloy. These results, which reveal a faster kinetics for the low-Mn alloy, are coherent with metallographic observations, and the driving force obtained through the determination of the austenite carbon concentration that was determined from the Mossbauer data using the Genins model for the Fe-C configurations in the fcc lattice. The kinetics parameters are further compared to those obtained in austempered ductile iron (ADI), by analyzing the graphite morphology influence on the austempering transformation.

  1. Influence of the Mn content on the kinetics of austempering transformation in compacted graphite cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Desimoni, J.; Gregorutti, R.; Laneri, K.; Sarutti, J.L.; Mercader, R.C.

    1999-11-01

    Moessbauer spectroscopy has been used to monitor the kinetics of austempering transformation in two compacted graphite (CG) cast irons alloyed with 0.11 and 0.58 wt pct of Mn, respectively. The phase relations were analyzed in terms of the Johnson-Mehl's equation, determining the kinetics parameters n (time exponent) and k (constant rate of the transformation). The values obtained were n = 1.4 and k = 7.47 x 10{sup {minus}3} s{sup {minus}1} for the low-Mn alloy, and n = 2.2 and k = 3.9 x 10{sup {minus}3} s{sup {minus}1} for the high-Mn alloy. These results, which reveal a faster kinetics for the low-Mn alloy, are coherent with metallographic observations, and the driving force obtained through the determination of the austenite carbon concentration that was determined from the Moessbauer data using the Genins model for the Fe-C configurations in the fcc lattice. The kinetics parameters are further compared to those obtained in austempered ductile iron (ADI), by analyzing the graphite morphology influence on the austempering transformation.

  2. 奥氏体等温转变铸铁研究的新进展%Recent Researches on Austempered Cast Irons

    Institute of Scientific and Technical Information of China (English)

    赵红; 徐卫平; 周继扬

    2001-01-01

    Recent researches on austempered cast irons have been reviewed. The present theories of the austempering transformation and the stability of high carbon austenite in ductile cast iron have been presented. The effects of chemical and mechanical deformation on austempering transformation have been discussed. The heat treatment processes, some mechanical properties and their applications of austempered gray iron, austempered compacted iron and austempered malleable iron have been introduced.%综述了奥氏体等温转变铸铁的最新研究成果。阐述了球墨铸铁奥氏体等温转变的最新理论及高碳奥氏体的稳定性,论述了化学成分及形变对奥氏体等温转变过程的影响,概述了奥氏体等温转变灰铸铁、蠕墨铸铁及可锻铸铁的热处理工艺特点、性能及其应用。

  3. Mechanical, physical, and corrosion characteristics of 2% vanadium alloyed ductile iron

    Science.gov (United States)

    Abdullah, Bulan; Jaffar, Ahmed; Alias, Siti Khadijah; Jaafar, Roseleena; Ramli, Abdullah; Faitullah, Ahmad

    2010-03-01

    This study was to investigate the effect of 2% vanadium alloyed austempered ductile iron on mechanical properties and microstructure and also to determine the desired austempering temperatures of vanadium alloyed ductile iron. In this study, specimens of 2%vanadium DI were produced by using the Y-block casting in the foundry lab. The specimen produced were machine according to the tensile and impact dimension followed the TSEN1002-1 and ASTM E23 standard. Then, austempering process was performed at the three different temperatures to the sample which are 500°, 600° and 700° in high temperature furnace. The specimens has been machine were undergoes the tensile, impact, density and hardness test. The microstructures were observed by using Olympus BX 41 M Microscopes image analysis system before and after etching by Nital 15%. Polarization test also were conduct between commercial DI and 2%V-DI. The results show that 2% vanadium alloyed ductile iron (2% V-DI) not only increases the nodule count and ferrite content in the microstructure, but also improves the mechanical properties such as tensile strength, impact toughness proportional to the austempered temperature as compared to unalloyed DI. The low corrosion rates also show for the 2% of vanadium alloyed compare to the commercial DI.

  4. Influence of Temper Temperature of Austenite on High-speed Cutting Properties of Austempering Ductile Iron (ADI)%奥氏体回火温度对等温淬火球墨铸铁(ADI) 高速切削加工性能的影响研究

    Institute of Scientific and Technical Information of China (English)

    吴少华; 郭旭红; 石皋莲

    2009-01-01

    等温淬火球墨铸铁(Austempering Ductile Iron,以下简称ADI)是一种新型的耐磨球铁材料.结合现有ADI材料的生产情况,选取300、350、400 ℃3个奥氏体回火温度,制备3组试样并测定力学性能.通过高速切削试验,研究了CC650陶瓷刀具高速干式切削不同性能ADI材料时刀具磨损形态和磨损机理,探讨了奥氏体回火温度对ADI高速切削时刀具磨损性能的关系.试验结果表明,奥氏体回火温度对ADI材料组织和力学性能有较大影响;奥氏体回火温度和ADI试件材料与CC650刀具磨损之间具有相关性;高速切削时,CC650刀具对ADI切削的磨损机制以磨粒磨损和扩散磨损为主.

  5. Erosion charcteristics of ductile iron with various matrix structures

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Kazumichi (Oita National Coll. of Technology (Japan)); Noguchi, Toru (Faculty of Engineering, Hokkaido Univ., Sapporo (Japan))

    1994-08-01

    Erosive wear tests were performed on austempered ductile iron (ADI), ferritic ductile iron (FDI) and pearlitic ductile iron (PDI) using a shot blast machine. Erosion damage was measured by the removed material volume at impact angles between 10 and 90 . The surface metal flow in vertical sections was also observed. The mechanism of erosive wear, the effect of impact angles, and differences in wear features of specimens were discussed. Experiment showed that, after an initial stage, the eroded volume increases almost linearly with blasting time in ADI, FDI and PDI. The erosion rate for ADI is about 1/10-1/25 of that for FDI and PDI. The surface hardness of eroded ADI specimens increased from the initial HV350 to HV700 after 600 s of blasting. The amount of retained austenite was measured as about 40% before the test, but decreased to about 3-5% by transformation of austenite to martensite, hardening the surface and lowering the erosion rate. It was shown that ADI has excellent erosion resistance and it is expected to find wide applications as a wear-resistant material. (orig.)

  6. A study on the effects of artifacts on fatigue limit of ductile cast iron with ferritic structure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hak [Yeungnam Univ., Gyeongsan (Korea, Republic of); Kim, Min Gun [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2000-10-01

    In this study, fatigue tests were performed to examine the effects of micro drill hole on fatigue limit of as cast and Austempered Ductile cast Iron (ADI) using the rotary bending fatigue tester. As results, micro drill holes (diameter{<=}0.4mm) did not influence the fatigue limit of ADI, compared to annealed ductile cast iron; the critical defect size of crack initiation, in ADI was larger than as cast. If the {radical}areas of micro drill hole and graphite nodule in ADI are comparable, crack initiates at the graphite nodule. When the ruggedness develops through austempering treatment process, microstructure on crack initiation at micro drill hole is tougher than that of as cast ductile cast iron.

  7. Investigation of the chip formation of austempered grey iron

    Science.gov (United States)

    Lung, S.; Klocke, F.; Döbbeler, B.; Krick, E.

    2016-10-01

    By a heat treatment process the strength and thus the field of applications of Grey Cast Iron (GI) can be increased to a range which is comparable to Compacted Graphite Iron (CGI). The microstructure of the resulting material consists of austenite and acicular ferrite. This material is named Austempered Grey Iron (AGI). Until now the material has not yet made its way to widespread use, due to the unknown machinability. For an economical use the machinability of the material must be at least at the level of CGI. This work deals with the chip formation, as an evaluation criterion for the machinability and represents a first step towards a comprehensive assessment of machining of AGI materials. To investigate the chip formation chip roots of three different AGI grades, a GI and a CGI were produced in a turning process. The chip roots were prepared to analyse the deformation of the microstructure during the chip formation.

  8. Effects of structure and defect on fatigue limit in high strength ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hak; Kim, Min Gun [Kangwon National Univ., Chunchon (Korea, Republic of)

    2000-05-01

    In this paper, the influence of several factors such as hardness, internal defect and non-propagating crack on fatigue limits was investigated with three kinds of ductile iron specimens. From the experimental results the fatigue limits were examined in relation with hardness and tensile strength in case of high strength specimens under austempering treatment; in consequence the marked improvement of fatigue limits were not showed. The maximum defect size was an important factor to predict and to evaluate the fatigue limits of ductile irons. And, the quantitative relationship between the fatigue limits({sigma}{sub {omega}}) and the maximum defect size({radical}area{sub max}) was expressed as {sigma}{sub {omega}}{sup n} {center_dot} {radical}area{sub max}=C{sub 2}. Also, it was possible to explain the difference for the fatigue limits in three ductile irons by introduction of the non-propagating crack rates.

  9. Relationships between microstructure and mechanical properties in ductile cast irons: a review; Relaciones entre la microestructura y las propiedades mecanicas en fundiciones nodulares: revison bibliografica

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, R.; Bermont, V. [Universidad de La Serena. La Serena. Chile (Chile); Martinez, V. [Universidad de Santiago. Santiago Chile (Chile)

    1999-07-01

    The progress achieved in the understanding of the relationships between the microstructure and the mechanical properties of ductile cast iron is reviewed. It is also described the applications of heat treatment of austempered to ductile irons (ADI), which have allowed to improve substantially the mechanical properties of these materials. It is proposed a research program to obtain the crack growth resistance under corrosive atmospheres and to model the mechanical properties. (Author) 83 refs.

  10. 46 CFR 56.60-15 - Ductile iron.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST... Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A... (incorporated by reference; see 46 CFR 56.01-2). (b) Ductile iron castings conforming to ASTM A...

  11. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Cast iron and ductile iron. 192.373... Regulators, and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron... cast iron pipe or ductile iron pipe is installed for use as a service line, the part of the...

  12. Microstructure vs. Near-threshold Fatigue Crack Growth Behavior of an Heat-treated Ductile Iron

    Directory of Open Access Journals (Sweden)

    Radomila KONEČNÁ

    2012-03-01

    Full Text Available Perferritic isothermal ductile iron (IDI® is an intermediate grade between the low-strength grades of austempered ductile iron (ADI and pearlitic ductile iron (DI recently developed by Zanardi Fonderie Italy. IDI is produced by heat-treating an unalloyed nodular cast iron. The specific matrix microstructure is called “Perferritic” and consists predominantly of ferrite and pearlite. Compared to the pearlitic grades of nodular ductile iron, IDI combines similar strength with higher toughness as a result of the isothermal heat treatment. In this contribution the fatigue crack growth resistance and Kath of IDI are investigated and correlated to mechanical properties and microstructural features. The threshold Ka was determined using the load shedding technique as per ASTM Standard E-647 using CT specimens extracted from a cast block. Tensile specimens were extracted from the broken CT halves and used to determine the static mechanical properties. A metallographic investigation was carried out to correlate structural features and mechanical properties.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1336

  13. Efecto del conteo de nódulos en la resistencia al desgaste por abrasión de los hierros dúctiles austemperados. // Effect of nodules count in the abrasive wear of austempered ductile irons.

    Directory of Open Access Journals (Sweden)

    C. J. Diez Cicero

    2009-05-01

    Full Text Available Entre los materiales metálicos de mayor demanda, la producción de hierro con grafito nodular,ocupa en la actualidad, uno de los lugares más importantes entre los hierros fundidos de altaresistencia, y con la introducción del tratamiento térmico de austemperado, aplicado a estasfundiciones, se da lugar a una nueva familia de materiales, caracterizados por su alta resistenciamecánica y elevada tenacidad, que mantienen la economía y facilidad de producción de lasfundiciones nodulares.Este trabajo, hace una valoración del comportamiento de hierros nodulares, con diferentes conteosde nódulos, a los que les fue aplicado el tratamiento de austemperado, y posteriormente se lessometió a ensayos de desgaste abrasivo.Con los resultados obtenidos, se hace un análisis de la influencia del conteo de nódulos en dichaspropiedades, así como también, de la interrelación del conteo de nódulos, con las variables detratamiento térmico utilizadas en las muestras ensayadas.Palabras claves: hierro nodular, conteo de nódulos, austemperado.__________________________________________________________________________AbstractBetween the metallic materials of greater demand, the iron production with nódular graphiteoccupies at the present time, one of the most important places between fused irons of highresistance, and with the introduction of the austemperado heat treatment of, applied to thesesmeltings, gives rise to a new family of materials, characterized by its high resistance mechanicaland elevated tenacity, that the economy and facility of production of the smeltings maintainnodulares. This work, makes a valuation of the iron behavior nodulares, with different counts fromnodules, to which the austemperado was applied treatment to them of, and later it was put underto them tests of abrasive wearing down. Of the obtained results, an analysis takes control of theinfluence of the count of nodules in these properties, as well as, of the interrelation of

  14. The influence of the hardening conditions on the mechanical properties of ductile cast iron

    Directory of Open Access Journals (Sweden)

    T. Giętka

    2010-01-01

    Full Text Available Ductile cast iron has been austempered according to two variants. The first treatment variant was austenitizing at a temperature tγ = 830, 860 and 900 0C and holding at a temperature tpi = 400 and 300 0C for 8 ÷ 64 min. Second variant treatment was two-phase austenitizing. Firstly, it was heated at a temperature tγ = 950 0C and after forecooling and chilling at a temperature tγ’ = 900, 860 and 830 0C isothermal process was conducted in the same conditions as in the first variant. The cast iron with ferritic matrix was austempered. After hardening the mechanical (Rp0,2, Rm and plastic (A5 properties were examined as well as the microstructure of matrix and hardness. It was noticed that the heat treatment carried out according to variants I and II lead to attaining cast iron of grade: ADI EN-GJS-800-8, EN-GJS-1200-2, EN-GJS-1400-1 according to PN–EN 1564 : 2000; in addition, ductility of these grades was 1,5÷4 times bigger than the mini-mum standard material requirements.

  15. Investigation of austenitizing temperature on wear behavior of austempered gray iron (AGI)

    Science.gov (United States)

    Sarkar, T.; Sutradhara, G.

    2016-09-01

    This study is about finding the effect of austenitizing temperature on microstructure and wear behavior of copper alloyed austempered gray iron (AGI), and then comparing it with an as- cast (solidified) state. Tensile and wear tests specimens are prepared from as-cast gray iron material, and austenitized at different temperatures and then austempered at a fixed austempering temperature. Resulting microstructures are characterized through optical microscopy, scanning electron microscope (SEM) and X-Ray diffraction. Wear test is carried out using a block-on-roller multi-tribotester with sliding speed of 1.86 m/sec. In this investigation, wear behavior of all these austempered materials are determined and co-related with the micro structure. Hence the wear surface under scanning electron microscope showed that wear occurred mainly due to adhesion and delamination under dry sliding condition. The test results indicate that the austenitizing temperature has remarkable effect on resultant micro structure and wear behavior of austempered materials. Wear behavior is also found to be dependent on the hardness, tensile strength, austenite content and carbon content in austenite. It is shown that coarse ausferrite micro structure exhibited higher wear depth than fine ausferrite microstructure.

  16. Study of the isothermal transformation of ductile iron with 0.5% Cu by electrical resistance measurement

    Science.gov (United States)

    Lin, B. Y.; Chen, E. T.; Lei, T. S.

    1995-10-01

    A computer-controlled system for measuring electrical resistance has been developed and used to study the isothermal transformation of austenite in a ductile iron (3.31 % C, 3.12 % Si, 0.22 % Mn, 0.55 % Cu). The ability of the technique to follow the isothermal decomposition of austenite was established by measurements on an AISI4340 steel. The times at which the austenite decomposed to primary ferrite, pearlite, and bainite were accurately detected. In the ductile iron, the formation of pearlite and of bainite was easily detected, and an isothermal transformation diagram was constructed from the results. The temperature range for the formation of bainite is especially important in producing austempered ductile iron (ADI) and was mapped. An initial stage of decomposition of austenite to ferrite and high-carbon austenite is followed by a time delay; then the high-carbon austenite decomposes to bainite. The formation of ADI requires austempering to a structure of ferrite and high-carbon austenite, then quenching to retain this structure, thus avoiding the formation of bainite. This is achieved by isothermal transformation into the time-delay region. For the ductile iron studied here, this time region was about 2.6 h at 400 °C and increased to 277 h at 300 °C.

  17. Study of the isothermal transformation of ductile iron with 0.5% Cu by electrical resistance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lin, B.Y.; Chen, E.T.; Lei, T.S. [National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering and Technology

    1995-10-01

    A computer-controlled system for measuring electrical resistance has been developed and used to study the isothermal transformation of austenite in a ductile iron (3.31% C, 3.12% Si, 0.22% mn, 0.55% Cu). The ability of the technique to follow the isothermal decomposition of austenite was established by measurements on an AISI 4340 steel. The times at which the austenite decomposed to primary ferrite, pearlite, and bainite were accurately detected. In the ductile iron, the formation of pearlite and of bainite was easily detected, and an isothermal transformation diagram was constructed from the results. The temperature range for the formation of bainite is especially important in producing austempered ductile iron (ADI) and was mapped. An initial stage of decomposition of austenite to ferrite and high-carbon austenite is followed by a time delay; then the high-carbon austenite decomposes to bainite. The formation of ADI requires austempering to a structure of ferrite and high-carbon austenite, then quenching to retain this structure, thus avoiding the formation of bainite. This is achieved by isothermal transformation into the time-delay region. For the ductile iron studied here, this time region was about 2.6 h at 400 C and increased to 277 h at 300 C.

  18. Analysis of nucleation modelling in ductile cast iron

    DEFF Research Database (Denmark)

    Moumeni, Elham; Tutum, Cem Celal; Tiedje, Niels Skat;

    2012-01-01

    Heterogeneous nucleation of nodular graphite at inclusions in ductile iron during eutectic solidification has been investigated. The experimental part of this work deals with casting of ductile iron samples with two different inoculants in four different thicknesses. Chemical analysis...

  19. Development of a High Strength Isothermally Heat-Treated Nodular Iron Road Wheel Arm

    Science.gov (United States)

    1985-03-31

    Ductile Iron . ADI = Austempered Ductile I ron. 19. ABSTRACT (Continue on...Characterization. 23 HAYES-ALBION CORP AUSTEMPERED DUCTILE IRON 200 KSI loo0 U’T.S 20o 1 YIELD KS oo" 10_ 10 - S% * . " ’"ELONGATION E-. I 50 HARDNESS 300 FT.LBS...manufacture, and testing of a proposed road wheel arm for the Ml tank. The material selected is bainitic ductile iron (BDI). This material made by the

  20. A characteristic of austenitic ductile iron

    Directory of Open Access Journals (Sweden)

    A. Tabor

    2007-04-01

    Full Text Available The article shows the results of investigations of the mechanical properties conducted on austenitic ductile iron with an addi-tion of 23-24% Ni. The examined mechanical properties included: tensile strength (Rm, proof stress (Rp0,2, elongation (A5 and reduction of area (Z at reduced and low temperatures.

  1. Transmission electron microscopy study of high temperature bainitic transformation in 1 wt.% Mn ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadabadi, M.N. [Tohoku Univ., Sendai (Japan); Niyama, E. [Tohoku Univ., Sendai (Japan); Echigoya, J. [Tohoku Univ., Sendai (Japan)

    1995-04-01

    A 1 wt.% Mn ductile iron austenitized at 900 C for 90 min and austempered at 375 C for different periods was used to study some aspects of bainitic reaction in high Mn austempered ductile iron with reference to carbide precipitation in bainitic ferrite. Transmission electron microscopy (TEM) energy-dispersive X-ray analysis (EDXA) study shows that precipitation of carbide in the ferritic component of bainite is a function of the local concentration of alloying elements. In other words, in the region near graphite where Si segregates and there is negative Mn segregation as well as carbon, the bainitic ferrite is carbide free. However, in the intercellular region where Mn segregates and Si is depleted, the ferritic component of bainite occurs together with very fine and almost uniformly distributed carbide. Furthermore, TEM-EDXA results show that the increase in Mn content not only delays stage I (the initial transformation of austenite to ferrite and retained austenite) of the bainitic reaction, but also delays stage II (decomposition of retained austenite to ferrite and carbide). ((orig.))

  2. The Performance Evalution of Ceramic And Carbide Cutting Tools In Machining of Austemepered Ductile Irons

    Directory of Open Access Journals (Sweden)

    Yahya IŞIK

    2014-12-01

    Full Text Available The aim of this research is to compare TiN (PVD coated Al2O3+Ti[C,N] mixed alumina-based (KY4400 ceramic and CVD coated carbide TiC+AI2O3+TiN (ISO P25 cutting tools in turning austempered ductile irons. Ductile cast iron samples were austenitized at 927°C and subsequently austempered for 1 hour at 400°C. The hardness of the workpiece material was measured and found to be 43.5 HRC. In the present work a series of tests were conducted in order to evaluate the tool performances by adopting tool life. In all experiments cutting forces, flank wear and surface roughness values were measured throughout the tool life. No cutting fluid was used during the turning operations. Study of the tool life and failure modes shows that tool life was determined by the flank wear and surface roughness generated on the workpiece. The main conclusion is that tool life of ceramic insert was longer than the coated carbide insert although much higher cutting speeds were used. 

  3. Modeling of Railway Wheels Made of Austempered Ductile Iron

    Directory of Open Access Journals (Sweden)

    Giętka T.

    2016-12-01

    Full Text Available A person is forced to travel constantly throughout its entire life. The more modern the society, the greater the pace of life, and the greater the need to be present in many places that are distant from each other. Rail transport occupies second place in this regard, after air transport. This means of transportation has many advantages, however the time of travel requires continuous improvement, in particular, to match the competition. One factor limiting the speed of travel is inter-operation between the wheels – rail kinematic pair. When rolling on a rail, a wheel is subject to wear, which unavoidably leads to its degradation. Frequent damage to both the wheel and the rail necessitates consideration of this problem. Because any changes to the rail are very expensive and time-consuming, this paper focuses on possible changes to the wheel.

  4. Fatigue crack tip damaging micromechanisms in a ferritic-pearlitic ductile cast iron

    Directory of Open Access Journals (Sweden)

    Francesco Iacoviello

    2015-07-01

    Full Text Available Due to the peculiar graphite elements shape, obtained by means of a chemical composition control (mainly small addition of elements like Mg, Ca or Ce, Ductile Cast Irons (DCIs are able to offer the good castability of gray irons with the high mechanical properties of irons (first of all, toughness. This interesting properties combination can be improved both by means of the chemical composition control and by means of different heat treatments(e.g. annealing, normalizing, quenching, austempering etc. In this work, fatigue crack tip damaging micromechanisms in a ferritic-pearlitic DCI were investigated by means of scanning electron microscope observations performed on a lateral surface of Compact Type (CT specimens during the fatigue crack propagation test (step by step procedure, performed according to the “load shedding procedure”. On the basis of the experimental results, different fatigue damaging micromechanisms were identified, both in the graphite nodules and in the ferritic – pearlitic matrix.

  5. 49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Remedial measures: Cast iron and ductile iron... for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to...

  6. Supporting the model of ductile iron dendritic solidification

    Energy Technology Data Exchange (ETDEWEB)

    Santos, H.M.C.M. [Porto Univ. (Portugal). Metall. and Mater. Dept.; Pinto, A.M.P. [Minho Univ. (Portugal). Mechanical Engineering Dept.; Jacinto, M.C.P.L. [Porto Polytechnic Inst. and INEGI, Porto (Portugal). Mechanical Engineering Dept.; Sa, C.P.M. [Porto Univ. (Portugal). Materials Center

    2000-08-01

    Microsegregation in ductile iron is generally accepted as modelled by a regular pattern: the graphite promoter elements are assumed to concentrate in the neighborhood of the graphite nodules and the carbide forming elements in the eutectic cell boundaries. The authors have conducted several microanalyses in several ductile irons and concluded that the microsegregation pattern does not agree with this model but supports the mechanism of dendritic ductile iron solidification. (orig.)

  7. Polyurethane coating for ductile iron pipes

    Directory of Open Access Journals (Sweden)

    WANG En-qing

    2006-05-01

    Full Text Available A special polyurethane coating designed for ductile iron pipe was developed. The effects of the ingredients on properties, such as viscosity, flow leveling, solidification-rate, adhesion and hardness, were researched. It was then analyzed in what ways the technical parameters, such as temperature and pressure, influence the coat quality. The results showed that the molar ratio and synthesizing conditions must be strictly controlled to obtain suitable pre-polymer viscosity by adjusting the formula ratio of the B component, satisfactory mechanical properties and cure rate can be obtained and bubbles in the coat can be avoided.

  8. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Science.gov (United States)

    2010-10-01

    ... cast iron or ductile iron lines. 192.487 Section 192.487 Transportation Other Regulations Relating to... iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... the purpose of this paragraph. (b) Localized corrosion pitting. Except for cast iron or ductile...

  9. Microstructural Characterization of Nodular Ductile Iron

    Energy Technology Data Exchange (ETDEWEB)

    Springer, H K

    2012-01-03

    The objective of this study is to quantify the graphite particle phase in nodular ductile iron (NDI). This study provides the basis for initializing microstructure in direct numerical simulations, as part of developing microstructure-fracture response models. The work presented here is a subset of a PhD dissertation on spall fracture in NDI. NDI is an ideal material for studying the influence of microstructure on ductile fracture because it contains a readily identifiable second-phase particle population, embedded in a ductile metallic matrix, which serves as primary void nucleation sites. Nucleated voids grow and coalesce under continued tensile loading, as part of the micromechanisms of ductile fracture, and lead to macroscopic failure. For this study, we used 2D optical microscopy and quantitative metallography relationships to characterize the volume fraction, size distribution, nearest-neighbor distance, and other higher-order metrics of the graphite particle phase. We found that the volume fraction was {Phi} = 0.115, the average particle diameter was d{sub avg} = 25.9 {mu}m, the Weibull shape and scaling parameters were {beta} = 1.8 and {eta} = 29.1 {mu}m, respectively, the (first) nearest neighbor distance was L{sub nn} = 32.4 {mu}m, the exponential coefficients for volume fraction fluctuations was A{sub {Phi}} = 1.89 and B{sub {Phi}} = -0.59, respectively. Based on reaching a coefficient-of-variation (COV) of 0.01, the representative volume element (RVE) size was determined to be 8.9L{sub nn} (288 {mu}m).

  10. Impact characteristics of austempered spheroidal graphite cast steel. Austemper kyujo kokuen chuko no shogeki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T.; Tada, S.; Abe, T. (Government Industrial Research Institute, Tohoku, Sendai (Japan))

    1993-08-25

    Austempered ductile cast iron (ADI) has excellent mechanical properties both in strength and toughness, but the Young's modulus of ADI is lower than that of steel because ADI contains much graphite. In order to obtain better mechanical properties than ADI, spheroidal graphite cast steel containing less graphite by volume was austempered. The Young's modulus of austempered spheroidal graphite cast steel (AGS) was 200 GPa, which was comparable to steel. The retained austenite volume of the sample containing 2.4% Si varied with the austempering conditions, but that of the sample containing 1.4% Si decreased in a shorter austempered time. As a result, it was found that Si affects stability of the retained austenite. Charpy impact value increased with increasing the retained austenite volume when the volume was above 15%. The impact value of AGS with 40% retained austenite was over twice as large as that of ADI austempered under the same conditions. 21 refs., 8 figs., 1 tab.

  11. Influence of matrix structure on the fatigue properties of an alloyed ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Toktas, Guelcan [Department of Mechanical Engineering, Balikesir University, 10145 Balikesir (Turkey)], E-mail: gzeytin@balikesir.edu.tr; Toktas, Alaaddin; Tayanc, Mustafa [Department of Mechanical Engineering, Balikesir University, 10145 Balikesir (Turkey)

    2008-07-01

    Rotary bending fatigue tests were conducted on ductile iron containing 1.25 wt% nickel, 1.03 wt% copper and 0.18 wt% molybdenum with various matrix structures. Several heat treatments were applied to obtain ferritic, pearlitic/ferritic, pearlitic, tempered martensitic, lower and upper ausferritic structures in the matrix of a pearlitic as-cast alloyed ductile iron. The tensile properties (ultimate tensile strength, 0.2% yield strength and percent elongation), the hardness and the microstructures of the matrixes were also investigated in addition to fatigue properties. Fractured surfaces of the fatigue specimens were examined by the scanning electron microscope. The results showed that the lowest hardness, tensile and fatigue properties were obtained for the ferritic structure and the values of these properties seemed to increase with rising pearlite content in the matrix. While the lower ausferritic structure had the highest fatigue strength, the upper ausferritic one showed low fatigue and tensile properties due to the formation of the second reaction during the austempering process.

  12. Hot Cutting of Real-Time Cast-Forged GS Ductile Iron for Automotive Rods

    Science.gov (United States)

    Fouilland, Laurence; Mansori, Mohamed El

    2011-01-01

    In the global economy context, automotive industry suppliers have to keep a constant advance on products design and manufacturing process. Concerning automotive rods, the substitution of forged steel by spherical graphite iron (SG iron) with high mechanical properties constitutes a valid economic alternative. Such rods are produced using a complex coupled process: casting and forging followed by an austempered heat treatment. The forging operation is capable to shape the cast rod which introduces hot deformation to increase mechanical properties of net-shape SG iron rod. However, the intermediate re-heating between casting and forging must be avoided to keep competitive manufacturing costs. A major concern of this new process development is the cracks produced in rod's surface which are consecutive to hot spruing involved after casting operations. This issue is addressed in this paper which discusses the physical mechanisms involved in the hot ductile damage of SG iron. Hot cutting tests were performed to simulate the spruing operation which shows the close interactions between microstructure, machining parameters and resulting damages. The damage mechanisms in terms of crack initiation and its growth have been studied with respect to the constituent phases (austenite+graphite nodules), the cut surface morphology and the hot cutting performance.

  13. Solidification, processing and properties of ductile cast iron

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat

    2010-01-01

    Ductile cast iron has been an important engineering material in the past 50 years. In that time, it has evolved from a complicated material that required the foundry metallurgist's highest skill and strict process control to being a commonly used material that can easily be produced with modern...... of the latest years of research indicate that ductile cast iron in the future will become a highly engineered material in which strict control of a range of alloy elements combined with intelligent design and highly advanced processing allows us to target properties to specific applications to a much higher...... and to illustrate how ductile iron's properties are optimised, the essentials of heat treatment are described too. It is the hope that researchers will find a comprehensive treatment of ductile cast iron metallurgy and that engineers and designers will be presented with the latest information on, and references to...

  14. Influence of Shot Peening on Abrasion Wear in Real Conditions of Ni-Cu-Ausferritic Ductile Iron

    Directory of Open Access Journals (Sweden)

    Wieczorek A. N.

    2016-12-01

    Full Text Available The paper presents results of the wear tests of chain wheels made of austempered ductile iron with various content of residual austenite. The aim of this study was to demonstrate the impact of the dynamic surface treatment (shot peening on wear properties of surface layers of the chain wheels tested that were subjected to the action of quartz abrasive. Apart from determining the value of the abrasive wear, examinations of the magnetic phase content in the microstructure were carried out and plots of hardness of the surface layer as a function of the distance from the surface and microstructure of the materials were prepared. Based on the results, the following was found: an increase in the abrasive wear and a reduction in the hardness of the surface layer of chain wheels subjected to shot peening, as well as reduction of susceptibility to negative action of the shot for cast irons with the structure of upper ausferrite.

  15. Mechanical Characterization of Nodular Ductile Iron

    Energy Technology Data Exchange (ETDEWEB)

    Springer, H K

    2012-01-03

    The objective of this study is to characterize the strength and fracture response of nodular ductile iron (NDI) and its underlying ferritic matrix phase. Quasistatic and split Hopkinson pressure bar (SHPB) compression tests were performed on NDI and a model material for the NDI matrix phase (Fe-Si alloy). Smooth and notch round bar (NRB) samples were loaded in tension until fracture to determine strain-at-failure with varying stress triaxiality. Multiple tests were performed on each small and large smooth bar samples to obtain fracture statistics with sample size. Fracture statistics are important for initializing simulations of fragmentation events. Johnson-Cook strength models were developed for the NDI and the Fe-Si alloy. NDI strength model parameters are: A = 525 MPa, B = 650 MPa, n = 0.6, and C = 0.0205. The average SHPB experimental strain-rate of 2312/s was used for the reference strain-rate in this model. Fe-Si alloy strength model parameters are: A=560 MPa, B = 625 MPa, n = 0.5, and C = 0.02. The average SHPB experimental strain-rate of 2850/s was used for the reference strain-rate in this model. A Johnson-Cook failure model was developed for NDI with model parameters: D{sub 1} = 0.029, D{sub 2} = 0.44, D{sub 3} = -1.5, and D{sub 4} = D{sub 5} = 0. An exponential relationship was developed for the elongation-at-failure statistics as a function of length-scale with model parameters: S{sub f1} = 0.108, S{sub f2} = -0.00169, and L{sub m} = 32.4 {mu}m. NDI strength and failure models, including failure statistics, will be used in continuum-scale simulations of explosively-driven ring fragmentation. The Fe-Si alloy strength model will be used in mesoscale simulations of spall fracture in NDI, where the NDI matrix phase is captured explicitly.

  16. As-Cast Acicular Ductile Aluminum Cast Iron

    Institute of Scientific and Technical Information of China (English)

    S M Mostafavi Kashani; S M A Boutorabi

    2009-01-01

    The effects of nickel (2.2%)and molybdenum (0.6%)additions on the kinetics, microstructure, and me-chanical properties of ductile aluminum cast iron were studied under the as-cast and tempered conditions. Test bars machined from cast to size samples were used for mechanical and metallurgical studies. The results showed that adding nickel and molybdenum to the base iron produced an upper bainitic structure, resulting in an increase in strength and hardness. The same trend was shown when the test bars were tempered at 300 ℃ in the range of 300℃ to 400 ℃. The elongation increased with increasing the temperature from 300 ℃ to 400 ℃. The carbon content of the retained austenite also increased with increasing the temperature. The results also showed that the kinetics, mi-crostructure, and mechanical properties of this iron were similar to those of Ni-Mo alloyed silicon ductile iron.

  17. Gears castings from ductile iron of improved abrasion wear resistance

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2011-10-01

    Full Text Available The aim of this study was to develop an industrial technological process for the manufacturing of castings from alloyed ductile iron characterized by improved resistance to abrasion wear. The outcome of the study was the implementation of developed technology under the industrial conditions of ASPAMET Foundry Plant and start up of production of a wide range of cast gears.

  18. Castability of ductile iron in thin walled castings (TWDI

    Directory of Open Access Journals (Sweden)

    M. Górny

    2008-10-01

    Full Text Available In work it has been presented results of influence of pouring temperature (Tp and carbon equivalent (CE on castability of ductile iron in thin walled castings with wall thickness of 1, 2 and 3 mm, respectively. Analysis was done on ductile iron with carbon equivalent ranging from 4.30 to 5.00 and pouring temperature varied from 1400 to 1500 oC. It has been shown that a statistical liner relationship exists between wall thickness and castability. Influence of CE and Tp on castability of cast iron flowing through channel with wall thickness of 2 and 3 mm can be presented by means of correlation equations (L = f(CE, Tp. Statistical analysis shows that pouring temperature has much higher influence on castability in comparison with influence of carbon equivalent.

  19. Thermo-Mechanical Processing and Properties of a Ductile Iron

    Energy Technology Data Exchange (ETDEWEB)

    Syn, C.K.; Lesuer, R.R.; Sherby, O.D.

    1997-07-14

    Thermo-mechanical processing of ductile irons is a potential method for enhancing their mechanical properties. A ductile cast iron containing 3.6% C, 2.6% Si and 0.045% Mg was continuously hot-and-warm rolled or one-step press-forged from a temperature in the austenite range (900{degrees}C-1100{degrees}C) to a temperature below the A, temperature. Various amounts of reduction were used (from 60% to more than 90%) followed by a short heat ent at 600`C. The heat ent lead to a structure of fine graphite in a matrix of ferrite and carbides. The hot-and- warm worked materials developed a pearlitic microstructure while the press-forged material developed a spheroidite-like carbide microstructure in the matrix. Cementite-denuded ferrite zones were developed around graphite stringers in the hot-and-warm worked materials, but such zones were absent in the press-forged material. Tensile properties including tensile strength and total elongation were measured along the direction parallel and transverse to the rolling direction and along the direction transverse to the press-forging direction. The tensile ductility and strength both increased with a decrease in the amount of hot-and-warm working. The press- forged materials showed higher strength (645 MPa) than the hot-and-warrn worked materials (575 MPa) when compared at the same ductility level (22% elongation).

  20. Solidification and microstructure of thin walled ductile cast iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin

    2006-01-01

    In the recent years there has been an increasing interest in light constructions in order to save weight in e.g. cars. Ductile cast iron has good mechanical properties but it is necessary to re­duce the wall thicknesses of the castings in order to reduce the weight. Reducing the wall thicknesses...... of the casting will increase the cooling rates and by that change the conditions for nucleation and growth during solidification....

  1. Effect of austempering temperature on cavitation behaviour of unalloyed ADI material

    Energy Technology Data Exchange (ETDEWEB)

    Dojcinovic, Marina [University of Belgrade, Faculty of Technology and Metallurgy, Karnegijeva 4, Belgrade (Serbia); Eric, Olivera [Innovation Centre, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, Belgrade (Serbia); Rajnovic, Dragan; Sidjanin, Leposava [Department of Production Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad (Serbia); Balos, Sebastian, E-mail: sebab@uns.ac.rs [Department of Production Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad (Serbia)

    2013-08-15

    This paper provides an in-depth study and description of cavitation damage and microstructural changes in two types of unalloyed austempered ductile iron (ADI). ADI materials used were austempered at 300 and 400 °C having ausferrite microstructure with 16 and 31.4% of retained austenite, respectively. Metallographic examination was carried out to study the morphology of their cavitation-damaged surfaces. Cavitation damage was initiated at graphite nodules as well as in the interface between a graphite nodule and an ausferrite matrix. Furthermore, microcracking and ferrite/retained austenite morphology were proved to be of great importance for cavitation resistance. Mass loss rate revealed that ADI austempered at 400 °C has a higher cavitation resistance in water than ADI austempered at 300 °C. A higher amount of retained austenite in ADI austempered at 400 °C played an important role in increasing cavitation resistance. The good cavitation behaviour of ADI austempered at 400 °C was due to the matrix hardening by stress assisted phase transformation of retained austenite into martensite (SATRAM) phenomenon, as shown by X-ray diffraction analysis. - Highlights: • Cavitation rate of two ADI materials was tested. • ADI material with a lower hardness has had a lower cavitation rate. • The main reason is microstructural transformations during cavitation. • SATRAM phenomenon increases cavitation resistance.

  2. Multiphysics and multiscale modelling of ductile cast iron solidification

    Directory of Open Access Journals (Sweden)

    D. Gurgul

    2010-01-01

    Full Text Available The presented model of ductile cast iron solidification is a typical sample of multiphysics and multiscale engineering system. This model takes into consideration the different time and spatial scales of accounted phenomenon of microstructure formation: heat diffusion, components mass diffusion in the liquid and solid phases, thermodynamic of phase transformation under the condition of inhomogeneous chemical composition of growing and vanishing phases, phase interface kinetics and grains nucleation.The results of two-dimensional modelling of the microstructure formation in the ductile cast iron (so called - Ductile Iron - DI are pre-sented. The cellular automaton model (CA was used for the simulation. Six states of CA cells were adopted to three phases above men-tioned (liquid, austenite and graphite and to three two-phase interfaces. For the modelling of concentration and temperature fields the numerical solution was used. The parabolic nonlinear differential equa-tions with a source term were solved by using the finite difference method and explicit scheme. The overlapping lattices with the same spatial step were used for the concentration field modelling and for the CA. The time scale of the temperature field for this lattice is about 104 times shorter. Due to above reasons the another lattice was used with a multiple spatial step and the same time step.

  3. Casting Ductile Iron in Layer Moulds Made from Ecological Sands

    Directory of Open Access Journals (Sweden)

    M. Rączka

    2012-09-01

    Full Text Available The article contains the results of tests performed under the target project in Hardtop Foundry Charsznica.The objective of the tests and studies was to develop a technology of making high-quality ductile iron castings, combined witheffective means of environmental protection. The studies presented in this article related to castings weighing from 1 to 300 kg made from ductile iron of grades 400-15 and 500-7, using two-layer moulds, where the facing and core sand was the sand with an alkaline organic binder, while backing sand was the sand with an inorganic geopolymer binder.A simplified method of sand reclamation was applied with possible reuse of the reclaim as an addition to the backing sand. The castiron spheroidising treatment and inoculation were selected taking into account the specific conditions of Hardtop Foundry. A pilot batch of castings was made, testing the gating and feeding systems and using exothermic sleeves on risers. The study confirmed the validity of the adopted concept of making ductile iron castings in layer moulds, while maintaining the content of sand with an organic binder at a level of maximum 15%.

  4. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Connections to cast iron or ductile...) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.369 Service lines: Connections to cast iron...

  5. Mechanisms and mechanics of porosity formation in ductile iron castings

    Directory of Open Access Journals (Sweden)

    M. Perzyk

    2007-12-01

    Full Text Available Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay’s mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.

  6. Melt Quality Evaluation of Ductile Iron by Pattern Recognition of Thermal Analysis Cooling Curves

    Institute of Scientific and Technical Information of China (English)

    LI Zhenhua; LI Yanxiang; ZHOU Rong

    2008-01-01

    The melt quality of ductile iron can be related to the melt's thermal analysis cooling curve. The freezing zone of the thermal analysis cooling curve was found to indicate the melt quality of the ductile iron. A comprehensive difference parameter, Ω, of the thermal analysis cooling curves was found to be related to the properties of ductile iron melts such as composition, temperature, and graphite morphology. As Ω ap- proached O, the thermal analysis cooling curves were found to come together with all the properties indicat- ing melt quality about the same. A database of thermal analysis cooling curves related to the properties of the ductile iron melts was set up as a basis for a method to accurately evaluate the melt quality of ductile iron by pattern recognition of thermal analysis cooling curves. The quality of a ductile iron melt can then be immediately determined by comparing its thermal analysis cooling curve freezing zone shape to those in the database.

  7. Some problems in the production of ductile irons by investment casting

    Institute of Scientific and Technical Information of China (English)

    Yu Bo; Cai Qizhou; Wei Bokang

    2008-01-01

    Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making,spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  8. Some problems in the production of ductile irons by investment casting

    OpenAIRE

    2008-01-01

    Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making, spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  9. Some problems in the production of ductile irons by investment casting

    Directory of Open Access Journals (Sweden)

    Yu Bo

    2008-02-01

    Full Text Available Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making, spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  10. Manufacture of Toothed Elements in Nanoausferritic Ductile Iron

    Directory of Open Access Journals (Sweden)

    Myszka D.

    2014-10-01

    Full Text Available The technology currently used for the fabrication of toothed wheels, gear couplings and chain drums involves the induction hardening process or hardening and tempering after carburising. All these processes take a long time and cause adverse changes in the dimensions and surface quality of products, requiring post-treatment machining to remove the resulting cavities. The paper proposes the implementation of gear elements made of ductile iron with nanoausferritic matrix obtained by a new appropriate heat treatment process. The new material offers good performance characteristics and nearly no need for the application of other technological processes commonly used in the manufacture of gears.

  11. Production of carbide-free thin ductile iron castings

    Institute of Scientific and Technical Information of China (English)

    M. Ashraf Sheikh

    2008-01-01

    The fast cooling rate of thin ductile iron castings requires special consideration to produce carbide-free castings. Extraor-dinary care was taken to select the charge to produce castings of 100-mm long round bars with 16-ram diameter. The castings show the presence of carbides in the bars. Seven melts were made with different temperatures and with different compositions to get rid of carbides. After chemical analyses, it was found that the extra purity of the charge with less than 0.008wt% sulfur in the castings was the cause of carbides. To remove the carbides fi'om the castings, sulfur should be added to the charge.

  12. The role of graphite morphology and matrix structure on low frequency thermal cycling of cast irons

    Indian Academy of Sciences (India)

    S Y Buni; N Raman; S Seshan

    2004-02-01

    Low frequency thermal cycling tests were carried out on four types of cast iron (viz., austempered ductile iron, pearlitic ductile iron, compacted/vermicular graphite iron and grey cast iron) at predetermined ranges of thermal cycling temperatures. The specimens were unconstrained. Results show that austempered ductile iron has the highest thermal cycling resistance, followed by pearlitic ductile iron and compacted graphite iron, while grey cast iron exhibits the lowest resistance. Microstructural analysis of test specimens subjected to thermal cycling indicates that matrix decomposition and grain growth are responsible for the reduction in hardness while graphite oxidation, de-cohesion and grain boundary separation are responsible for the reduction in the modulus of elasticity upon thermal cycling.

  13. Kinetic model of ductile iron solidification with experimental verification

    Directory of Open Access Journals (Sweden)

    W. Kapturkiewicz

    2009-10-01

    Full Text Available A solidification model for ductile iron, including Weibull formula for nodule count has been presented. From this model, the following can be determined: cooling curves, kinetics of austenite and eutectic nucleation, austenite and eutectic growth velocity, volume fraction, distribution of Si and P both in austenite and eutectic grain with distribution in casting section.In the developed model of nodular graphite iron casting solidification, the correctness of the mathematical model has been experimentally verified in the range of the most significant factors, which include temperature field, the value of maximum undercooling, and the graphite nodule count interrelated with the casting cross-section. Literature offers practically no data on so confronted process model and simulation program.

  14. Thermal analysis of ductile iron in thin walled casting

    Directory of Open Access Journals (Sweden)

    M. Górny

    2007-12-01

    Full Text Available Hypereutectic ductile iron was cast in self hardening moulding sand to produce castings with the shape of Archimedes spirals and with wall thickness of 1, 2 and 3 mm. Inmould technique was used to produce thin wall ductile iron (TWDI. In this work it has been carried out thermal analysis in spiral with 3 mm wall thickness. The present work provides results of thermal analysis, that are initial temperature of metal in mould cavity, velocity of metal stream as well as solidification time. Measurement of temperature shows that there is essential its drop during filling of mould cavity and amounts 230 oC for distance 700 mm from the beginning of spiral. On the basic on first derivative of temperature versus time characteristic solidification points were distinguish, namely solidification of primary graphite, austenite dendrite and eutectic. Experimental measurements of temperature drop during filling of mould cavity along with microscopic examinations of castings structure can be used to verify computer modeling and simulation of fluid flow and thermal field in TWDI.

  15. Structure of ductile iron in thin walled castings

    Directory of Open Access Journals (Sweden)

    M. Górny

    2007-12-01

    Full Text Available It this work it has been shown that it is possible to produce thin wall ductile iron (TWDI castings with considerably length using Archimedes spiral with wall thickness of 1, 2 and 3 mm. Inmould technique was used to produce TWDI. It has been estimated castability and metallographic investigations were made using different moulding materials. From castability measurements result that it is possible to obtain thin wall ductile iron castings with wall thickness down to 1 mm with castability of 200 mm. Using mould with small ability to absorb heat castability increases twice. At wall thickness equal 3 mm castability reaches 1000 mm and using LDASC sand its value increases to over 1500 mm. Structure parameters for different wall thickness and moulding materials (graphite nodule count, ferrite and cementite fraction are plotted versus distance from the beginning of spiral. It is shown strong influence of LDASC sand (material with small ability to absorb heat on structure parameters (NF, Vf i VC revealing gradient character of TWDI.

  16. Homogeneous formation of epsilon carbides within the austenite during the isothermal transformation of a ductile iron at 410 °C

    Science.gov (United States)

    Gutierrez, I.; Aranzabal, J.; Castro, F.; Urcola, J. J.

    1995-05-01

    The transformation of a ductile iron at 410 °C for different times, after austenitization for 30 minutes at 900 °C, is analyzed in detail. Upper bainite and a high volume fraction of austenite are formed for intermediate annealing times. A certain amount of martensite is observed after quenching not only for short transformation times but also for intermediate times. The formation of the martensite on cooling after intermediate transformation times is due to the decrease in carbon concentration of the retained austenite because of the homogeneous precipitation of epsilon carbides within. This homogeneous precipitation of epsilon carbide inside austenite is unambiguously observed. The epsilon carbide, pre-precipitated in austenite, which transforms to martensite on cooling, continues growing in the martensite after transformation. For long times of austempering at 410 °C, some complex large carbides or silicocarbides are formed, probably from the epsilon carbide, which result in the total decomposition of austenite.

  17. Effect of bainite transformation and retained austenite on mechanical properties of austempered spheroidal graphite cast steel

    Science.gov (United States)

    Takahashi, Toshio; Abe, Toshihiko; Tada, Shuji

    1996-06-01

    Austempered ductile iron (ADI) has excellent mechanical properties, but its Young's modulus is low. Austempered spheroidal graphite cast steel (AGS) has been developed in order to obtain a new material with superior mechanical properties to ADI. Its carbon content (approximately 1.0 pct) is almost one-third that of a standard ADI; thus, the volume of graphite is also less. Young's modulus of AGS is 195 to 200 GPa and is comparable to that of steel. Austempered spheroidal graphite cast steel has an approximately 200 MPa higher tensile strength than ADI and twice the Charpy absorbed energy of ADI. The impact properties and the elongation are enhanced with increasing volume fraction of carbon-enriched retained austenite. At the austempering temperature of 650 K, the volume fraction of austenite is approximately 40 pct for 120 minutes in the 2.4 pct Si alloy, although it decreases rapidly in the 1.4 pct Si alloy. The X-ray diffraction analysis shows that appropriate quantity of silicon retards the decomposition of the carbon-enriched retained austenite. For austempering at 570 K, the amount of the carbon-enriched austenite decreases and the ferrite is supersaturated with carbon, resulting in high tensile strength but low toughness.

  18. Effect of bainite transformation and retained austenite on mechanical properties of austempered spheroidal graphite cast steel

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Toshio; Abe, Toshihiko; Tada, Shuji [Tohoku National Industrial Research Inst., Sendai (Japan). Materials Engineering Div.

    1996-06-01

    Austempered ductile iron (ADI) has excellent mechanical properties, but its Young`s modulus is low. Austempered spheroidal graphite cast steel (AGS) has been developed in order to obtain a new material with superior mechanical properties to ADI. Its carbon content (approximately 1.0 pct) is almost one-third that of a standard ADI; thus, the volume of graphite is also less. Young`s modulus of AGS is 195 to 200 GPa and is comparable to that of steel. Austempered spheroidal graphite cast steel has an approximately 200 MPa higher tensile strength than ADI and twice the Charpy absorbed energy of ADI. The impact properties and the elongation are enhanced with increasing volume fraction of carbon-enriched retained austenite. At the austempering temperature of 650 K, the volume fraction of austenite is approximately 40 pct for 120 minutes in the 2.4 pct Si alloy, although it decreases rapidly in the 1.4 pct Si alloy. The X-ray diffraction analysis shows that appropriate quantity of silicon retards the decomposition of the carbon-enriched retained austenite. For austempering at 570 K, the amount of the carbon-enriched austenite decreases and the ferrite is supersaturated with carbon, resulting in high tensile strength but low toughness.

  19. Approximate creep feed grinding of austempared ductile cast iron; Osutenpa kyujo kokuen chutetsu no kin`i kuripu fido kensaku

    Energy Technology Data Exchange (ETDEWEB)

    Nakamitsu, K.; Shimizu, K. [Oita National College of Technology, Oita (Japan)

    1996-10-01

    Austempered ductile cast iron (ADI) was subjected to approximate creep feed grinding to measure and observe the grinding ratio, hardness of ground surface, grinding resistance, production of burrs, roughness of ground surface, and grinding burn to investigate the best abrasive grains and grinding conditions. The grinding ratio of SiC grains was far better than that of Al2O3 grains, being about 10 times or more. Surface hardness of ADI ground by SiC grains changed little, but that ground by Al2O3 grains increased. As regards grinding resistance, that of Al2O3 grains have less slope and tangential component forces, but that of SiC grains increased with the increase in the ground volume. While burrs produced in grinding with SiC grains are secondary burrs, those produced in grinding with Al2O3 grains are primary burrs. In comparison with the normal grinding, grinding burn was produced on the ground surface, complicate striped patterns and grinding burns were produced by chattering particularly in grinding with Al2O3 grains. 10 refs., 11 figs., 2 tabs.

  20. 奥贝球墨铸铁力学性能综合指标模糊数学评价法%Synthetic Evaluation on Indices of Mechanics Properties of Ductile Iron by Fuzzy Mathematics

    Institute of Scientific and Technical Information of China (English)

    何希杰; 张勇; 劳学苏

    2014-01-01

    分析了奥贝球墨铸铁在不同奥氏体化温度参数ATP,奥氏体化时间参数AtP,等温温度参数ITP和等温时间参数ItP等热处理条件下力学性能的技术指标,提出了奥贝球铁力学性能指标模糊数学综合评价方法,通过大量计算得出了综合评价结果。计算结果表明,力学性能在奥氏体化温度920℃,奥氏体化时间90min等温温度380和等温时间60min时综合指标最好,在奥氏体化温度940℃,奥氏体化时间30min等温温度350℃和等温时间120min时综合指标最差。本文研究结果为进一步研究球墨铸铁力学性能和新性能球墨铸铁提供了重要的依据。本评价方法对于工程技术方案评价也具有实用价值。%The technical indices of mechanics properties of ductile iron with different heat treatment parameters have been researched.The synthetic evaluating method by fuzzy mathematics on those indices has been offered.The evaluating result of technical indices of mechanics properties has been obtained with lot of calculation,resulting in that the best mechanics property occured in conditions of austempering temperature 920 ℃,austempering holding time 90 min,isothermal temperature 380 ℃and isothermal holding time 60 min while the worst occured with austempering temperature 940 ℃,austempering holding time 30 min,isothermal temperature 350℃and isothermal holding time 120 min.23 others samples were between them successively.The result may have an important practical signiifcance for further research of mechanics properties of ductile iron and for developing new properties of ductile iron.The evaluating method in this paper may have an important practical signiifcance for the evaluating on the other project.

  1. Influence of isothermal transformation dwell on tensile and fatigue properties of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Vechet, S.; Hanzlikova, K. [Brno Univ. of Technology, Brno (Czech Republic); Kohout, J. [Military Academy in Brno, Brno (Czech Republic)

    2005-07-01

    Two ADI heats transformed at temperatures of 400 and 380 C during temporal range from 2 minutes to 9 hours were studied in details, with emphasis on structure composition and mechanical properties (tensile and fatigue properties were determined). In the case of the shortest dwells the level of mechanical properties is influenced by martensite, which occurs in the structure as a result of subsequent cooling. UTS and yield stress increase slightly with the dwell of isothermal transformation while the values of elongation to fracture as well as of fatigue limit are very closely dependent on the amount of the retained austenite in the microstructure. (orig.)

  2. Fatigue properties of ductile cast iron containing chunky graphite

    Energy Technology Data Exchange (ETDEWEB)

    Ferro, P., E-mail: ferro@gest.unipd.it [Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, I-36100 Vicenza (Italy); Lazzarin, P.; Berto, F. [Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, I-36100 Vicenza (Italy)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer Experimental determination of high cycle fatigue properties of EN-GJS-400. Black-Right-Pointing-Pointer Evaluation of the influence of chunky graphite morphology on fatigue life. Black-Right-Pointing-Pointer Metallurgical analysis and microstructural parameters determination. Black-Right-Pointing-Pointer Nodule counting and nodularity rating. - Abstract: This work deals with experimental determination of high cycle fatigue properties of EN-GJS-400 ductile cast iron containing chunky graphite. Constant amplitude axial tests were performed at room temperature under a nominal load ratio R = 0. In order to evaluate the influence of chunky graphite morphology on fatigue life, fatigue tests were carried out also on a second set of specimens without this microstructural defect. All samples were taken from the core of a large casting component. Metallurgical analyses were performed on all the samples and some important microstructural parameters (nodule count and nodularity rating, among others) were measured and compared. It was found that a mean content of 40% of chunky graphite in the microstructure (with respect to total graphite content) does not influence significantly the fatigue strength properties of the analysed cast iron. Such result was attributed to the presence of microporosity detected on the surface fracture of the specimens by means of electron scanning microscope.

  3. Surface Graphite Degeneration in Ductile Iron Castings for Resin Molds

    Institute of Scientific and Technical Information of China (English)

    Iulian Riposan; Mihai Chisamera; Stelian Stan; Torbjorn Skaland

    2008-01-01

    The objective of this paper is to review the factors influencing the formation of degenerated graph-ite layers on the surfaces of ductile iron castings for chemical rosins-acid molding and coro-making systems and how to reduce this defect. In the rosin 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 metal-mold 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 res-ins have a profound effect on the frequency and severity of surface pinholes, but a limited influence on sur-face graphite degeneration.

  4. Evaluation of producing technique factors affecting the matrix microstructure of as-cast ductile iron castings

    Directory of Open Access Journals (Sweden)

    S. Bockus

    2011-01-01

    Full Text Available The objective of this paper was to investigate some important parameters related to ductile iron matrix microstructure. Ductile iron round bars of various diameters in order to achieve various cooling rates were obtained in different conditions. None heat treatment was used to obtain different pearlite contents in the microstructures. The correlation between kind of inoculants, specimens size, carbon equivalent, and matrix microstructure was investigated. The results demonstrated that the slow cooling rate, inoculants with rare earth elements, and relatively little residual magnesium content decreased the pearlite content. This study is of great importance for the development of new economical methods for production of ductile iron castings.

  5. Comparative study of TIG and SMAW root welding passes on ductile iron cast weldability

    Directory of Open Access Journals (Sweden)

    J. Cárcel-Carrasco

    2017-01-01

    Full Text Available This work compares the weldability of ductile iron when: (I a root weld is applied with a tungsten inert gas (TIG process using an Inconel 625 source rod and filler welds are subsequently applied using coated electrodes with 97,6%Ni; and (II welds on ductile iron exclusively made using the manual shielded metal arc welding technique (SMAW. Both types of welds are performed on ductile iron specimen test plates that are subjected to preheat and post-weld annealing treatments. Samples with TIG root-welding pass shown higher hardness but slightly lower ductility and strength. Both types of welding achieved better ductile and strength properties than ones found in literature.

  6. Ductile cast iron obtaining by Inmold method with use of LOST FOAM process

    Directory of Open Access Journals (Sweden)

    T. Pacyniak

    2010-01-01

    Full Text Available The possibility of manufacturing of ductile cast iron castings by Inmold method with use of LOST FOAM process was presented in this work. The spheroidization was carried out by magnesium master alloy in amounts of 1% casting mass. Nodulizer was located in the reactive chamber in the gating system made of foamed polystyrene. Pretests showed, that there are technical possibilities of manufacturing of casts from ductile cast iron in the LOST FOAM process with use of spheroidization in mould.

  7. Ductile cast iron obtaining by Inmold method with use of LOST FOAM process

    OpenAIRE

    T. Pacyniak; R. Kaczorowski

    2010-01-01

    The possibility of manufacturing of ductile cast iron castings by Inmold method with use of LOST FOAM process was presented in this work. The spheroidization was carried out by magnesium master alloy in amounts of 1% casting mass. Nodulizer was located in the reactive chamber in the gating system made of foamed polystyrene. Pretests showed, that there are technical possibilities of manufacturing of casts from ductile cast iron in the LOST FOAM process with use of spheroidization in mould.

  8. Effect of Microstructure on Exhaust Manifold Cracks Produced From SiMo Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    Havva Kazdal Zeytin; Ceylan Kubilay; H(u)seyin Aydin; Ali Aslan Ebrinc; Bilal Aydemir

    2009-01-01

    Ductile cast irons are used as high temperature materials in internal combustion engines,because they are microstructurally stable at high operating temperatures.SiMo granular graphite cast irons contain Fe2 MoC and M6C carbide precipitates due to their higher concentration of both silicon and molybdenum.The microstructure of these cast irons consists of carbides dispersed within the ferrite matrix.The microstructural change and the crack formation mechanism in manifolds produced from SiMo ductile iron are studied.Chemical analysis,optical and scanning electron microscope studies have been completed and evaluated.

  9. Automatic quantitative analysis of microstructure of ductile cast iron using digital image processing

    Directory of Open Access Journals (Sweden)

    Abhijit Malage

    2015-09-01

    Full Text Available Ductile cast iron is preferred as nodular iron or spheroidal graphite iron. Ductile cast iron contains graphite in form of discrete nodules and matrix of ferrite and perlite. In order to determine the mechanical properties, one needs to determine volume of phases in matrix and nodularity in the microstructure of metal sample. Manual methods available for this, are time consuming and accuracy depends on expertize. The paper proposes a novel method for automatic quantitative analysis of microstructure of Ferritic Pearlitic Ductile Iron which calculates volume of phases and nodularity of that sample. This gives results within a very short time (approximately 5 sec with 98% accuracy for volume phases of matrices and 90% of accuracy for nodule detection and analysis which are in the range of standard specified for SG 500/7 and validated by metallurgist.

  10. Study on the serialization and applications of low carbon ductile iron

    Institute of Scientific and Technical Information of China (English)

    SHU Xin-fu; SHU Rui; CHANG Dian-cun; ZHANG Xiao-long; ZHU Yan-dong; LI Ling-fang; LI Yu-zhong

    2005-01-01

    Both the production process and the chemical composition of Sx were studied, and the serialization of iow carbon ductile iron was also discussed. It was indicated that Sx modifier was sensitive to the carbon equivalent (CE) of molten iron and to some alloying elements too. When the CE of molten iron and the contents of alloying elements were changed, the content of Sx must be revised with the change correspondingly. Low carbon ductile iron can be stably changed into the one that non-carbon acicular ferrite and retained austenite (about 25%-28%) by quasi-casting bainitic process of using Sx-2 modifier treated Si-Mn-Cr-Cu-alloyed low carbon molten iron. The austenitic low carbon as-cast ductile iron could be obtained by the Ni-Si-Cr 35 5 2 percent alloys molten iron with less than 2% carbon treated by type Sx-3 modifier. The high-toughness ferritic low carbon as-cast ductile iron which contained more than 85 % ferrite in matrix could be got after the molten iron treated by type Sx-4 modifier, and it's elongation was more than 10 %.

  11. Pin-On-Disc Characterization of Brass/Ferritic and Pearlitic Ductile Iron Rubbing Pair

    Science.gov (United States)

    Çetin, Melik

    2011-04-01

    Wear behaviour of special brass produced through two different methods (centrifugal and sand casting) was investigated. The wear tests were carried out at sliding velocities of 0.2 ms-1, 0.3 ms-1, 0.4 ms-1 and 0.5 ms-1 and under 10 N, 20 N, and 40 N variable loads. The sliding distance was 600 m for all the tests. A pin-on-disc device with round specimen inserts was used to conduct friction and wear tests in which the friction coefficient, the contact temperature and the linear wear of the tribo-pairs were continuously recorded against sliding distance. Two different materials were used as the counterparts, namely ferritic ductile iron equivalent to GGG40 and pearlitic ductile iron equivalent to GGG60. The microstructures and wear scars of the brass specimens were examined by optical, scanning electron microscopy (SEM) and X-ray microanalyses by EDAX. A correlation between hardness and wear volume rate was established for the investigated centrifugally cast and sand cast brass specimens. The volume rate of specimens produced by sand casting method was generally found to be higher than those of centrifugally cast specimens. Ferritic ductile counterpart led to higher wear volume rate than pearlitic ductile counterpart for the both specimens. Severe abrasive wear scars were observed for the sand cast specimens/ferritic ductile iron pair. However, severe adhesive wear took place for the centrifugally cast specimen/pearlitic ductile iron pair.

  12. A Study the relationship between composition, structure and properties of ductile iron in continuous casting

    OpenAIRE

    2011-01-01

    The developed empirical relationships have practical significance and used for determine the structural composition of iron on known data of express-analysis and for optimization technical process of obtaining castings of ductile iron at Public corporation «Gomel foundry «TSENTROLIT».

  13. Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

    Directory of Open Access Journals (Sweden)

    Vasková I.

    2014-10-01

    Full Text Available Ductile cast iron (GS has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

  14. Evaluation of Zinc-Coated Ductile Iron Pipe

    Energy Technology Data Exchange (ETDEWEB)

    Shipilov, Sergei A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-30

    Oak Ridge National Laboratory (ORNL) received $1m in funding from the U.S. Bureau of Reclamation in order to evaluate the performance of zinc-coated ductile iron pipe (DIP) in highly- and severely-corrosive soils. The project started in May 2016 and a final report will be issued March 31, 2017. The project is being led by the Corrosion Science and Technology Group in the Materials Science and Technology Division at ORNL. This interim report is based on the work performed by an ORNL multidisciplinary team in the last two months. The project has been broken down into four tasks. The first task is to characterize commercially available DIP. Specimens from the three major U.S. DIP manufacturers were purchased for this study via third party vendors and are being characterized. The second task is to evaluate available data on DIP corrosion in soils. The largest data set was collected by the National Bureau of Standards (now NIST) from 1910-1952 and included 95 different kinds of soil at 128 sites across the country. Because of the large amount of data and limited agreement on what defines “corrosive” soil, staff from the Computational Sciences and Engineering Division have been consulted and are currently analyzing the data using existing algorithms to look for trends between the corrosion rates and the various soil characteristics such as resistivity and pH. The third task is to develop a long-term test plan to evaluate DIP and the fourth task is to develop an accelerated test procedure to reduce the time required to evaluate soil corrosion by 1-2 orders of magnitude. By developing a better understanding of what makes a soil corrosive, including the chemical and physical properties, it may be possible to model the long-term behavior of DIP. A full report on the work will be submitted by the March 2017 deadline. It appears that a sustained, multi-year effort in this area would be of great benefit to the Bureau of Reclamation, to the DIP industry and to the country

  15. A new method for chill and shrinkage control in ladle treated ductile iron

    Institute of Scientific and Technical Information of China (English)

    Torbj(o)rn Skaland

    2006-01-01

    The paper is undertaken with the objective of describing a new method for treating ductile cast iron in a ladle process, where the main objective is to minimize formation of eutectic carbides and shrinkage porosity during solidification. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and inoculant alloys. By nucleating properties it is understood the number and potency of nuclei formed by an alloy addition. The nodularizer and inoculant additions also influence ductile iron solidification shrinkage. Some alloys may give good protection against shrinkage while others tend to promote more shrinkage.The use of vanous rare earth elements is found to have a pronounced impact on these conditions. It has been discovered that the use of pure lanthanum as the primary rare earth source in the magnesium ferrosilicon nodularizer surprisingly further improves the performance of the ductile iron ladle treatment method compared to similar methods using cerium or mishmetal bearing nodularizers. The nucleating properties are substantially improved and the risk for carbides (chill) and shrinkage formation in the sandwich or tundish ladle treated ductile iron is then minimized.The paper describes this new ladle treatment concept in detail, and gives examples from successful testing of the new nodularizing technology and how it simultaneously affects and minimizes critical ductile iron chill and shrinkage tendencies.

  16. Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

    Directory of Open Access Journals (Sweden)

    M. Górny

    2009-01-01

    Full Text Available In paper it is presented thin wall ductile iron casting (TWDI as a substitute of aluminium alloy casting. Upper control arm made of ductile iron with wall thickness ranging from 2 – 3.7 mm was produced by inmold process. Structure, mechanical properties and computer simulations were investigated. Structural analysis of TWDI shows pearlitic-ferritic matrix free from chills and porosity. Mechanical testing disclose superior ultimate tensile strength (Rm, yield strength (Rp0,2 and slightly lower elongation (E of TWDI in comparison with forged control arm made of aluminium alloy (6061-T6. Moreover results of computer simulation of static loading for tested control arms are presented. Analysis show that the light-weight ductile iron casting can be loaded to similar working conditions as the forged Al alloy without any potential failures.

  17. Influence of the section size and holding time on the graphite parameters of ductile iron production

    Directory of Open Access Journals (Sweden)

    S. Bockus

    2009-01-01

    Full Text Available This work was conducted to establish the conditions required to produce a desirable structure of the castings of various section sizes. This investigation was focused on the study of the influence of cooling rate or section size and holding time on graphite parameters of the ductile iron. Plates having thickness between 3 and 50mm were cast in sand molds using the same melt. The present investigation has shown that the section size of ductile iron castings and holding time had strong effect on the graphite parameters of the castings.

  18. Ordered iron aluminide alloys having an improved room-temperature ductility and method thereof

    Science.gov (United States)

    Sikka, Vinod K.

    1992-01-01

    A process is disclosed for improving the room temperature ductility and strength of iron aluminide intermetallic alloys. The process involves thermomechanically working an iron aluminide alloy by means which produce an elongated grain structure. The worked alloy is then heated at a temperature in the range of about 650.degree. C. to about 800.degree. C. to produce a B2-type crystal structure. The alloy is rapidly cooled in a moisture free atmosphere to retain the B2-type crystal structure at room temperature, thus providing an alloy having improved room temperature ductility and strength.

  19. Fatigue Life Prediction of Ductile Iron Based on DE-SVM Algorithm

    Science.gov (United States)

    Yiqun, Ma; Xiaoping, Wang; lun, An

    the model, predicting fatigue life of ductile iron, based on SVM (Support Vector Machine, SVM) has been established. For it is easy to fall into local optimum during parameter optimization of SVM, DE (Differential Evolution algorithm, DE) algorithm was adopted to optimize to improve prediction precision. Fatigue life of ductile iron is predicted combining with concrete examples, and simulation experiment to optimize SVM is conducted adopting GA (Genetic Algorithm), ACO (Ant Colony Optimization) and POS (Partial Swarm Optimization). Results reveal that DE-SVM algorithm is of a better prediction performance.

  20. Development of thermal simulation system for heavy section ductile iron solidification

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate that the temperature in the system responses exactly to the inputted control data and the temperature control error is less than ± 0.5 %. It is convenient to simulate solidification of heavy section ductile iron using this new system. Results of thermal simulation experiments show that the differences in nodularity and number of graphite nodule per unit area in the thermal simulation specimen and the actual heavy section block is less than 5 % and 10 %, respectively.

  1. Draft ASME code case on ductile cast iron for transport packaging

    Energy Technology Data Exchange (ETDEWEB)

    Saegusa, T. [Central Research Inst. of Electric Power Industry, Abiko (Japan); Arai, T. [Central Research Inst. of Electric Power Industry, Yokosuka (Japan); Hirose, M. [Nuclear Fuel Transport Co., Ltd., Tokyo (Japan); Kobayashi, T. [Nippon Chuzo, Kawasaki (Japan); Tezuka, Y. [Mitsubishi Materials Co., Tokyo (Japan); Urabe, N. [Kokan Keisoku K. K., Kawasaki (Japan); Hueggenberg, R. [GNB, Essen (Germany)

    2004-07-01

    The current Rules for Construction of ''Containment Systems for Storage and Transport Packagings of Spent Nuclear Fuel and High Level Radioactive Material and Waste'' of Division 3 in Section III of ASME Code (2001 Edition) does not include ductile cast iron in its list of materials permitted for use. The Rules specify required fracture toughness values of ferritic steel material for nominal wall thickness 5/8 to 12 inches (16 to 305 mm). New rule for ductile cast iron for transport packaging of which wall thickness is greater than 12 inches (305mm) is required.

  2. Investigation of solidification of thin walled ductile cast iron using temperature measurement

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels

    2005-01-01

    Investigation of solidification of thin walled ductile cast iron can be improved using temperature measurement. This article includes some background of the precautions that have to be taken when measuring temperatures in thin walled castings. The aim is to minimize influence of temperature...... measurement on castings and to get sufficient response time of thermocouples. Investigation of thin wall ductile iron has been performed with temperature measurement in plates with thickness between 2,8 and 8mm. The cooling curves achieved are combined with examination of the microstructure in order to reveal...

  3. Modeling the elastic behavior of ductile cast iron including anisotropy in the graphite nodules

    DEFF Research Database (Denmark)

    Andriollo, Tito; Thorborg, Jesper; Hattel, Jesper Henri

    2016-01-01

    This paper presents a micro-mechanical approach to model the intrinsic elastic anisotropy of the graphite particles in ductile iron. Contrary to most of the published works in the field, the constitutive behavior is directly derived on the basis of the nodule characteristic internal structure......, composed of graphite platelets arranged into conical sectors. In this way, the large uncertainty traditionally associated with local mechanical measurements of micro-hardness is eliminated. The proposed anisotropic description is validated by simulating the macroscopic ductile iron elastic response...

  4. Thermal distortion of disc-shaped ductile iron castings in vertically parted moulds

    DEFF Research Database (Denmark)

    Vedel-Smith, Nikolaj Kjelgaard; Rasmussen, Jakob; Tiedje, Niels Skat

    2015-01-01

    A disc-shaped casting with an inner boss and an outer rim, separated by a thin walled section, was examined. This measurable deformation varied with the feeding modulus. The influence of alloy composition, particularly Si content, was examined with a pearlitic ductile iron (EN-GJS-500......-7) and a fully ferritic ductile iron (EN-GJS-450-10). The experiment showed that both the alloy composition and choice of feeder influenced the degreeof deformation measured in the finished casting. It was found that the deformation of the pearlitic alloy was influenced controllably by changing the feeder...

  5. Effects of austempering conditions on the microstructures and mechanical properties in Fe-0.9%C-2.3%Si-0.3%Mn steel

    Science.gov (United States)

    Son, Je-Young; Kim, Ji-Hun; Kim, Won-Bae; Ye, Byung-Joon

    2010-06-01

    In this study, the effect of the microstructure and mechanical properties of austempered high-carbon (0.9 %C) high-silicon (2.3 %Si) cast steel were investigated. The specimens were austenitised for 60 min. at 900 °C, and austempered at 260 °C, 320 °C, and 380 °C for periods of time ranging from 30 min to 240 min. After receiving this heat treatment, the mechanical properties were measured using both a tensile test and hardness test. To analyze the microstructure, an optical microscope was used and an X-ray diffraction (XRD) analysis was carried out. In this study, high carbon high silicon cast steel without graphite and with higher tensile strength (1300 MPa to 2200 MPa) and elongation (˜25 %), when compared to austempered ductile cast iron (ADI), was developed. When the austempering temperature was at 260 °C, the microstructures were low ausferrite, but at 380 °C, an upper ausferrite structure was formed. As the austempering temperature increased from 260 to 380 °C, the ultimate tensile strength and hardness decreased, but the elongation and retained austenite volume fraction increased. In addition, the microstructures were coarser.

  6. Development and Testing of a Linear Polarization Resistance Corrosion Rate Probe for Ductile Iron Pipe (Web Report 4361)

    Science.gov (United States)

    The North American water and wastewater community has hundreds of millions of feet of ductile iron pipe in service. Only a portion of the inventory has any form of external corrosion control. Ductile iron pipe, in certain environments, is subject to external corrosion.Linear Pola...

  7. Undercooling, nodule count and carbides in thin walled ductile cast iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2008-01-01

    Ductile cast iron has been cast in plate thicknesses between 2 to 8 mm. The temperature has been measured during the solidification and the graphite nodule count and size distribution together with the type and amount of carbides have been analysed afterwards. Low nodule count gives higher...

  8. Numerical modelling of thin-walled hypereutectic ductile cast iron parts

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Hattel, Jesper Henri; Tiedje, Niels Skat

    2006-01-01

    Solidification of hypereutectic thin-walled ductile cast iron has been modelled in one dimension taking into account the precipitation of off-eutectic austenite dendrites during solidification. The simulations have been compared with casting experiments on plate geometries with plate thicknesses...

  9. 3-D Analysis of Graphite Nodules in Ductile Cast Iron Using FIB-SEM

    DEFF Research Database (Denmark)

    D'Angelo, Luca; Jespersen, Freja N.; MacDonald, A. Nicole;

    Ductile cast iron samples were analysed in a Focused Ion Beam Scanning Electron Microscope, FIB-SEM. The focussed ion beam was used to carefully remove layers of the graphite nodules to reveal internal structures in the nodules. The sample preparation and milling procedure for sectioning graphite...

  10. Three-dimensional local residual stress and orientation gradients near graphite nodules in ductile cast iron

    DEFF Research Database (Denmark)

    Zhang, Yubin; Andriollo, Tito; Fæster, Søren;

    2016-01-01

    A synchrotron technique, differential aperture X-ray microscopy (DAXM), has been applied to characterize the microstructure and analyze the local mesoscale residual elastic strain fields around graphite nodules embedded in ferrite matrix grains in ductile cast iron. Compressive residual elastic...

  11. Nucleation and solidification of thin walled ductile iron - Experiments and numerical simulation

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2005-01-01

    Investigation of solidification of thin walled ductile cast iron has been performed based on experiments and numerical simulation. The experiments were based on temperature and microstructure examination. Results of the experiments have been compared with a 1-D numerical solidification model...

  12. The effects of manganese phosphate coating wear resistance of chilled ductile iron camshafts

    Directory of Open Access Journals (Sweden)

    Tarık Gün

    2013-06-01

    Full Text Available The ductile iron camshafts are preferred due to high toughness and strength features in the automobile industry. Through the coolants used in the camshaft production high surface hardness is achieved. In this study, the wear resistance effects of ductile iron chill produced camshafts coated with manganese phosphate are researched. The camshaft surfaces produced as ductile iron chill are coated with manganese phosphate. The coating surfaces are observed with scanning electron microscope (SEM. The changes occurring on the cam profiles are measured with running the wear resistance of the manganese phosphate coating on the camshafts on the engine test rig with 30 minutes interval in 1000rpm. In order to compare the results of uncoated camshafts run on engines are checked against simultaneously. As result, the manganese phosphate coated cams were 2,8 times less worn up than the uncoated cams. The manganese phosphate coated ductile iron chill camshafts are less worn up according to uncoated camshafts because of the oil holding feature of manganese phosphate coating.

  13. Development,Application and Problem of Ductile Iron Lost Foam Casting Technology in China

    Institute of Scientific and Technical Information of China (English)

    He Wenhao; Ye Shengping; Han Xiaohong; Tang Suoyun

    2010-01-01

    @@ Lost-foam casting is a 21st century green casting technology.Over the past decade,there has been an extraordinary development in lost-foam casting in China;and ductile iron lost-foam casting has developed even more rapidly in foundry equipment,foundry raw materials,and casting engineers.

  14. Effects of Silicon on Mechanical Properties and Fracture Toughness of Heavy-Section Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    Liang Song

    2015-01-01

    Full Text Available The effects of silicon (Si on the mechanical properties and fracture toughness of heavy-section ductile cast iron were investigated to develop material for spent-nuclear-fuel containers. Two castings with different Si contents of 1.78 wt.% and 2.74 wt.% were prepared. Four positions in the castings from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties’ testing. Results show that the tensile strength, elongation, impact toughness and fracture toughness at different positions of the two castings decrease with the decrease in cooling rate. With an increase in Si content, the graphite morphology and the mechanical properties at the same position deteriorate. Decreasing cooling rate changes the impact fracture morphology from a mixed ductile-brittle fracture to a brittle fracture. The fracture morphology of fracture toughness is changed from ductile to brittle fracture. When the Si content exceeds 1.78 wt.%, the impact and fracture toughness fracture morphology transforms from ductile to brittle fracture. The in-situ scanning electronic microscope (SEM tensile experiments were first used to observe the dynamic tensile process. The influence of the vermicular and temper graphite on fracture formation of heavy section ductile iron was investigated.

  15. Production and Machining of Thin Wall Gray and Ductile Cast Iron

    Energy Technology Data Exchange (ETDEWEB)

    Fleischman, E.H. (INEEL POC); Li, H.; Griffin, R.; Bates, C.E.; Eleftheriou, E.

    2000-11-03

    The University of Alabama at Birmingham, in cooperation with the American Foundry Society, companies across North America, with support from the U.S. Department of Energy, is conducting a project to develop an understanding of the factors that control the machinability of cast gray and ductile iron. Differences of as much as 500% have been found in machinability have been observed at the same strength. The most machinable irons were those with a high cell counts and few carbonitride inclusions. Additions of tin and copper can be added to both gray and ductile iron to stabilize the pearlite, but excessive additions (above those required to produce the desired pearlite content) degrade the machinability.

  16. Effect of silicon content and defects on the lifetime of ductile cast iron

    Directory of Open Access Journals (Sweden)

    Alhussein Akram

    2014-06-01

    Full Text Available In this work, the influence of microstructure on the mechanical properties has been studied for different grades of ferritic ductile cast iron. Mechanical tests were carried out and the effect of silicon on the resistance of material was well noticed. An increasing silicon content increases the strength and decreases the ductility of material. The lifetime and endurance limit of material were affected by the presence of defects in material and microstructure heterogeneity. Metallurgical characterizations showed that the silicon was highly segregated around graphite nodules which leads to the initiation of cracks. The presence of defects causes the stress concentration and leads to the initiation and propagation of cracks.

  17. Influence of cooling rate and antimony addition content on graphite morphology and mechanical properties of a ductile iron

    Directory of Open Access Journals (Sweden)

    Liu Zhe

    2012-05-01

    Full Text Available Cooling rate and inoculation practice can greatly affect the graphite morphology of ductile irons. In the present research, the effects of the cooling rate and antimony addition on the graphite morphology and mechanical properties of ductile irons have been studied. Three ductile iron castings were prepared through solidification under cooling conditions S (slow, M (medium and F (fast. The cooling rates around the equilibrium eutectic temperature (1,150 ℃ for these cooling conditions (S, M and F were set at 0.21 ℃·min-1, 0.32 ℃·min-1 and 0.37 ℃·min-1, respectively. In addition, four ductile iron castings were prepared by adding 0.01%, 0.02%, 0.03% and 0.04% (by weight antimony, respectively under the slow cooling condition. The results show that the nodularity index, tensile strength and hardness of the ductile iron castings without antimony addition are all improved with the increase of cooling rate, while the ductile iron casting solidified under the medium cooling rate possesses the largest number of graphite nodules. Furthermore, for the four antimony containing castings, the graphite morphology and tensile strength are also improved by the antimony additions, and the effect of antimony addition is intensified when the addition increases from 0.01% to 0.03%. Moreover, the rare earth elements (REE/antimony ratio of 2 appears to be the most effective for fine nodular graphite formation in ductile iron.

  18. Damage Mechanics of Ferrite Ductile Iron under Uniaxial Stress

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-hai; LI Guo-lu; FU Han-guang; HAO Xiao-yan; LIU Gen-sheng

    2003-01-01

    According to the principle of damage mechanics, the damage characteristics of ferrite nodular cast iron under uniaxial stress were studied by measuring electric resistance. The results show that the damage in nodular cast iron occurs when the applied stress is more than a certain extent, and the damage variable increases with stress. The evolutional law of damage variable as a function of stress was obtained. The damage threshold of nodular cast iron increases with nodularity, but it is below the yield strength, which provides reference significance to the design of machinery structure and the choice of materials. The critical damage variable is not related to the nodularity, which is about 0.060-0.068.

  19. Effect of Austempering on the Wear Resistance of Austempered Ductile Iron%等温淬火工艺对ADI耐磨性的影响

    Institute of Scientific and Technical Information of China (English)

    高颂; 刘金海; 边泊乾; 徐卓

    2008-01-01

    研究了等温淬火工艺对ADI耐磨性的影响.结果表明:当等温温度在260~380℃时,随着等温淬火温度的升高,耐磨性逐渐降低;360℃等温淬火时,耐磨性最差,继续升高等温淬火温度,耐磨性又有升高的趋势;当等温时间在30~120 min,随着等温淬火时间的增加,耐磨性逐渐降低;等温淬火60 min时,耐磨性最差;等温淬火时问继续延长,耐磨性又有升高的趋势.

  20. Effect of Lanthanum on Nodule Count and Nodularity of Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The present study aims at finding out the effect of the addition of a single rare earth element, that is, lanthanum on the nodularity and nodule count of ductile iron under controlled conditions. For this purpose, four melts with different compositions were made, using a 28 kg inductotherm medium frequency induction furnace. The temperature was carefully maintained between 1400 and 1450 ℃ for these heats. A good quality charge consisting of Sorel metal, ferrosilicon, Swedish iron, ferrosilicon magnesium, and ferrosilicon lanthanum was used for the production of melts. A vertically parted sand mould was used for casting of 10 test bars made from local silica sand. Standard coin samples were chill-cast to conduct chemical analysis of the ductile iron. Microstructure study of the samples was conducted using a Leica optical microscope. Nodule count and nodularity of the samples were carried out using an image analyzer. The results obtained indicated that with the increased addition of lanthanum the nodule count of ductile iron increased, thus making it evident that it played a significant role in increasing the mechanical properties. The highest nodule count of 467 was obtained with the addition of 0.03% lanthanum. However, the effect of lanthanum on nodularity was negligible with nodularity ranging from 81% to 83%.

  1. The studies of mechanical properties and structure of ADI as function of austempering parameters

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2010-10-01

    Full Text Available The results of study of ductile iron austempered using different parameters of austempering are presented. The aim of the investigations was to look closer into mechanical properties of this very attractive cast material. The experiment was carried out with commercial EN-GJS-500-7 grade ductile iron. The specimens were first solution heat treated 1 hour in 910oC and then isothermally quenched for different time in molten tin of different temperature. The mechanical properties heat treated specimens were tested using tensile test machine to evaluate Rp,0.2, Rm and A10. Moreover Brinell hardness tests were carried out for structure investigation conventional light microscopy only was used. It was discovered, that low yield strength ADI obtained for short time quenching at 275oC exhibited high strengthening effect while tensile strained. So it was concluded that this had to by cause by large amount of untransformed austenite, which FCC lattice providing large number of glide systems.

  2. Experimental analysis of flow of ductile cast iron in stream lined gating systems

    DEFF Research Database (Denmark)

    Skov-Hansen, Søren; Green, Nick; Tiedje, Niels Skat

    2008-01-01

    Streamlined gating systems have been developed for production of high integrity ductile cast iron parts. Flow of ductile cast iron in streamlined gating systems was studied in glass fronted sand moulds where flow in the gating system and casting was recorded by a digital video camera. These results...... are compared with real time x-ray recordings of melt flow. Results show that flow patterns are the same using both techniques. The glass fronted moulds give global information on flow in the whole gating system and casting while the x-ray analysis gives detailed information on specific areas. The experiments...... show how the quality of pouring, design of ingates, design of bends and flow over cores influence melt flow and act to determine the quality of the castings....

  3. Numerical modelling of solidification of thin walled hypereutectic ductile cast iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Hattel, Jesper; Tiedje, Niels

    2006-01-01

    Numerical simulation of solidification of ductile cast iron is normally based on a model where graphite nodules are surrounded by an austenite shell. The two phases are then growing as two concentric spheres governed by diffusion of carbon through the austenite shell. Experiments have however shown...... simulation of thin-walled ductile iron castings. Simulations have been performed with a 1-D numerical solidi¬fication model that includes the precipitation of non-eutectic austenite during the eutectic stage. Results from the simulations have been compared with experimental castings with wall thick...... the presence of austenite dendrites even in hypereutectic castings. In thin-walled castings the presence of austenite dendrites is even more pronounced, which increases the risk of shrinkage porosities. This off-eutectic austenite is therefore an important part that should be taken into account during...

  4. Influence of rare earths on shrinkage porosity in thin walled ductile cast iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2009-01-01

    Ductile cast iron has been cast in test bars with thickness from 2 to 10 mm. The rare earth elements La and Ce have been added to some of the castings to evaluate their influence on microstructure and shrinkage tendency. Both La and Ce increased the graphite nodule count, especially for thickness...... the temperature T-1, which is controlled by the growth of off-eutectic austenite dendrites, increased the shrinkage tendency....

  5. Effect of small additions of vanadium and niobium on structure and mechanical properties of ductile iron

    Directory of Open Access Journals (Sweden)

    Fraś E.

    2007-01-01

    Full Text Available Results of investigations of influence of small additions of vanadium (up to 0,15 % V and niobium (up to 0,04% Nb on structure of ductile iron is presented in this work. Effect of these additions on distribution of graphite nodule diameter, nodule count, fraction and carbide count have been determined. Investigations of effect of small additions of vanadium and niobium on mechanical properties taking into account tensile strength, yield strength and elongation have also been made.

  6. Effect of Bi on graphite morphology and mechanical properties of heavy section ductile cast iron

    Directory of Open Access Journals (Sweden)

    Song Liang

    2014-03-01

    Full Text Available To improve the mechanical properties of heavy section ductile cast iron, bismuth (Bi was introduced into the iron. Five castings with different Bi content from 0 to 0.014 wt.% were prepared; and four positions in the casting from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties test. The effect of the Bi content on the graphite morphology and mechanical properties of heavy section ductile cast iron were investigated. Results show that the tensile strength, elongation and impact toughness at different positions in the five castings decrease with a decrease in cooling rate. With an increase in Bi content, the graphite morphology and the mechanical properties at the same position are improved, and the improvement of mechanical properties is obvious when the Bi content is no higher than 0.011wt.%. But when the Bi content is further increased to 0.014wt.%, the improvement of mechanical properties is not obvious due to the increase of chunky graphite number and the aggregation of chunky graphite. With an increase in Bi content, the tensile fracture mechanism is changed from brittle to mixture ductile-brittle fracture.

  7. Review of current research and application of ductile cast iron quality monitoring technologies in Chinese foundry industry

    OpenAIRE

    Da-yong Li; Zhen-yu Xu; Xu-liang Ma

    2015-01-01

    There is a long history of studying and making use of ductile cast iron in China. Over the years, the foundrymen in China have carried out a lot of valuable research and development work for measuring parameters and controlling the quality in ductile cast iron production. Many methods, such as rapid metallographic phase, thermal analysis, eutectic expansion ratio, surface tension measurement, melt electrical resistivity, oxygen and sulfur activity measurement, ultrasonic measurement and sound...

  8. Development of acceptance criteria and damage tolerance analyzes of the ductile iron insert; Framtagning av acceptanskriterier samt skadetaalighetsanalyser av segjaernsinsatsen

    Energy Technology Data Exchange (ETDEWEB)

    Dillstroem, Peter; Alverlind, Lars; Andersson, Magnus (Inspecta Technology AB (Sweden))

    2010-01-15

    SKB intends to qualify a test system for detection and sizing of defects deemed to be relevant to the ductile iron insert. In support of this qualification, a damage tolerance analysis indicating the current qualification targets, given assumed damage and failure modes. This report describes the damage tolerance analyzes of different types of defects that are considered relevant of the ductile iron insert. The results are reported separately for each test area (zone) and type of insert (BWRs and PWRs)

  9. Modelling the solidification of ductile cast iron parts with varying wall thicknesses

    DEFF Research Database (Denmark)

    Bjerre, Mathias Karsten; Tiedje, Niels Skat; Thorborg, Jesper

    2015-01-01

    ] with a 2D FE solution of the heat conduction equation is developed in an in-house code and model parameters are calibrated using experimental data from representative castings made of ductile cast iron. The main focus is on the influence of casting thickness and resulting local cooling conditions......In the present paper modelling the solidification of cast iron parts is considered. Common for previous efforts in this field is that they have mainly considered thin walled to medium thickness castings. Hence, a numerical model combining the solidification model presented by Lesoultet al. [1...

  10. Microstructure and Hot Oxidation Resistance of SiMo Ductile Cast Irons Containing Si-Mo-Al

    Science.gov (United States)

    Ibrahim, Mervat M.; Nofal, Adel; Mourad, M. M.

    2016-12-01

    SiMo ductile cast irons are used as high-temperature materials in automotive components, because they are microstructurally stable at high operating temperatures. The effect of different amounts of Si and Mo as well as the addition of 3 wt pct Al on the microstructure, high-temperature oxidation, and mechanical properties of SiMo ductile cast iron was studied. Dilatometric measurements of SiMo ductile iron exhibited obvious differences in the transformation temperature A 1 due to presence of Al and the increase of Si. The microstructure of the SiMo alloys without Al addition showed outstanding nodularity and uniform nodule distribution. However, by adding 3 wt pct Al to low Si-SiMo ductile iron, some compacted graphite was observed. The results of oxidation experiments indicated that high Si-SiMo ductile iron containing 4 and 4.9 wt pct Si had superior resistance to lower Si-SiMo and SiMo ductile iron containing 3 wt pct Al. The results showed also that with increasing Si up to 4.9 wt pct or by replacing a part of Si with 3 wt pct Al, tensile strength increased while elongation and impact toughness decreased.

  11. RESEARCH OF THE FEEDING SPEED ADOPTING CORED-WIRE METHOD TO SPHEROIDIZE DUCTILE IRON MELT

    Institute of Scientific and Technical Information of China (English)

    G.W.Chang; H.X.Wang; X.D.Yue; H.L.Zhang

    2008-01-01

    For settling the question of feeding speed in applying the cored-wire method to spheroidize ductile iron melt, ANSYS software was applied to simulate the heat transfer and mass transfer, and the melt time of the steel strip in the iron melt was determined by linking the heat transfer and mass transfer, and then the feeding speed was calculated. Conclusions have been drawn that the iron layer was formed on the surface of the cored-wire during the wire-feeding process. The thickness is 0.073 mm when the temperature of the iron melt is 1500℃, the time from formation to remelting of the iron layer is 0.063 s. When the temperature of the iron melt is below 1500℃, the time taken for the steel strip to melt is rapidly shortened. When the temperature of the iron melt is above 1500℃, the variation amplitude of the steel strip melt change with time is gradually diminished. The melt time of the steel strip is rapidly increased with the increase of the steel strip thickness. When the temperature of the iron melt is 1500℃ and the carbon content is 4%, the melt time of a steel strip, which has a thickness of 0.5 mm, is thrice that of a steel strip whose thickness is 0.3 mm. The calculation results of the feeding speed are basically in agreement with the applied feeding speed in the factory.

  12. Modern Cored Wire Injection 2PE-9 Method in the Production of Ductile Iron

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2012-04-01

    Full Text Available The results of studies on the use of modern two cored wires injection method for production of nodular graphite cast iron with use of unique implementation of drum ladle as a treatment/ transport and casting ladle instead vertical treatment ladle was described. The injection of length of Ø 9mm wires, cored: in FeSi + Mg nodulariser mixture and inoculant master alloy is a treatment method which can be used to produce iron melted in coreless induction furnace. This paper describes the results of using this method for possibility production of ductile iron under specific industrial conditions. In this case was taken ductile iron with material designation: EN-GJS-450- 10 Grade according PN-EN 1563:2000. Microstructure of 28 trials was controlled on internally used sample which has been correlated with standard sample before. The paper presents typical metallic matrix and graphite characteristic. Additionally, mechanical properties were checked in one experiment. Because of further possibility treatment temperature reduction only the rough magnesium recovery and cost of this new method are given.

  13. Influencing factors on as-cast and heat treated 400-18 ductile iron grade characteristics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As-cast and heat-treated 400-18 ductile iron (DI) grade was obtained in different foundry conditions, as metallic charge, Mg-treatment alloy and inoculation. It was found that the Pearlitic Influence Factor (Px) and Antinodulizing Complex Factor (K1) have an important influence on property of DI, depending on the Mn and P level, the metallurgical quality of iron melt, rare earth (RE) and inoculation. It was also found that the influence of Mn is depended on the phosphorus and residual elements level in ductile iron. Less than 0.03%P and 0.2%Mn and Px<2.0 are the basic conditions to obtain as-cast ferritic structure. At the same lower level of Mn and P, the increasing of residual elements (Px>2.0) determines presence of pearlite in as-cast structure, while ferrite structure is obtained after a short annealing heat treatment. Lower level of phosphorus (P<0.025%) and residual elements (Px<2.0) allow to use relative high Mn content (0.32%-0.38%), in condition of ferritic structure, including in as-cast state. High P (0.04%-0.045%) and Mn (0.25%-0.35%) content stabilized pearlite, especially at lower level of residual elements (Px <2.0). Antinodulizing action of elements was counteracted up to K1=2.0 level, by RE included in Mg-treatment alloy, which are beneficial for K1<1.2 and compulsory for K1>1.2. Si has a significant influence on the mechanical properties of heat treated ductile irons: an important decreasing of elongation level and a moderate increasing of yield and tensile strength and their ratio in 150-170 HB typical hardness field. A typical final chemical composition for as-cast 400-18 ductile iron could include 3.5%-3.7%C, 2.4%-2.5%Si, max.0.18%Mn, max.0.025%P, max.0.01%S, 0.04%-0.05%Mgres.for Px<1.5 and K1<1.1. High purity pig iron, RE-bearing FeSiMg and powerful inoculant are also recommended.

  14. Discussion on the Naming of Austempered Ductile Iron%奥贝球铁的命名方式

    Institute of Scientific and Technical Information of China (English)

    王峥; 刘瑞玲; 史玉芳; 刁美艳

    2007-01-01

    介绍和总结了奥贝球铁的不同命名方式.指出了等温淬火球铁(ADI)、奥铁球铁(Ausferrite)、贝氏体球铁等几种名称,并对其作了进一步理解和认识,可为有关方面的研究提供参考依据.

  15. Producing Process of Austempered Ductile Iron%奥贝球铁的生产工艺

    Institute of Scientific and Technical Information of China (English)

    王峥; 刘瑞玲; 王忠民

    2007-01-01

    奥贝球铁具有很多优点,在各个领域中广泛应用.其生产技术尤其受到重视.详细叙述了奥贝球铁的各种生产方式,包括传统的等温淬火工艺,分级冷却工艺,连续冷却工艺和铸态、准铸态奥贝球铁生产工艺.

  16. TEM observation of microstructure of austempered ductile iron%奥-贝球铁显微组织的TEM观察

    Institute of Scientific and Technical Information of China (English)

    郑春明; 周巧琴; 戴品强

    2004-01-01

    本文采用透射电镜观察分析非合金奥-贝球铁显微组织,结果发现:球铁中石墨形态为由中心向外辐射呈层状结构;非合金球铁经900℃奥氏体化、370℃等温1h后,基体组织为贝氏体铁素体和奥氏体,且有两种形貌:一种是贝氏体铁素体和奥氏体呈板条状相间分布,另一种是奥氏体呈块状分布在贝氏体铁素体中.

  17. Influence of process parameters on the properties of austempered ductile iron (ADI examined with the use of data mining methods

    Directory of Open Access Journals (Sweden)

    D. Wilk-Kołodziejczyk

    2016-10-01

    Full Text Available The article presents opportunities offered by the data mining analysis as applied to studies of the effect of process parameters on the mechanical properties of ADI. The applied methods of regression trees and cluster analysis allow for the detection of relationships between parameters and also allow determination of strength and form of the impact of different factors. The results of this study allow the creation of knowledge bases for systems supporting the decision-making process in technology.

  18. 合金球墨铸铁的渗硼动力学研究%Study of Boriding Kinetics for Alloyed Ductile Irons

    Institute of Scientific and Technical Information of China (English)

    Fábio Edson Mariani; Galtiere Correa Rego; Luiz Carlos Casteletti; Amadeu Lombardi Neto; George Edward Totten3

    2016-01-01

    Boriding thermochemical treatment produces layers with high hardness which improves the tribological performance of ductile cast iron while the austempering treatment improves the mechanical performance of the substrate.In this work,samples of the ductile cast iron alloyed with copper,copper-nickel and copper-nickel-molybdenum were borided in a salt bath (borax +aluminum)at temperatures of 850,900 and 950 ℃ during 2 and 4 hours.The data for the layers obtained were used to determine the diffusion coefficients and activation energies of this process.The results of the calculated diffusion coefficients were similar to those obtained by the direct measurements of the layer thicknesses.For the sample alloyed with Cu or Cu-Ni the activation energy obtained was 141.27 kJ/mol,and for the sample alloyed with Cu-Ni-Mo the value was 212.98 kJ/mol.The statistical parameters and the correlation coefficients (R)showed satisfactory agreement.%渗硼层硬度高,能改善球墨铸铁(以下简称球铁)的摩擦学性能,而等温淬火能提高基体的力学性能。对含Cu、Cu-Ni和Cu-Ni-Mo的合金球铁试样进行了盐浴(硼砂+铝)渗硼,渗硼温度分别为850℃、900℃和950℃,时间2 h和4 h。通过所获得的渗层数据确定合金球铁渗硼的扩散系数和激活能。计算求得的扩散系数与通过直接测定渗层厚度得出的扩散系数相接近。含Cu或Cu-Ni的试样激活能为141.27 kJ/mol,而含Cu-Ni-Mo的试样激活能为212.98 kJ/mol。统计参数与相关系数(R)吻合良好。

  19. Machinability of clean thin-wall gray and ductile iron castings. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bates, C.E.; Littleton, H.E.; Eleftheriou, E.; Griffin, R.D.; Dwyer, Z.B.; DelSorbo, C.; Sprague, J.

    1997-02-01

    First phase was to develop a laboratory technique for evaluating the machinability of gray and ductile iron; longer term goal is to learn how to modify the foundry process to produce castings meeting all specified mechanical properties while providing improved machining behavior. Microcarbides present in the irons were found to dominate the machinability of iron. Pearlitic irons with acceptable machinability contain 8.9 to 10.5 wt% microcarbides. The weight fraction microcarbides in the iron is influenced by carbide forming element concentrations, presence of elements that retard carbon diffusion, and cooling rate from the eutectic through the eutectoid temperature range. Tool wear rate increased at higher surface machining speeds and fraction microcarbides; all irons containing above 11.5% microcarbides had poor machinability. Graphite size, shape, distribution, etc. had a lesser effect on machinability. Reducing the addition of a foundry grade Ca and Al bearing 75% FeSi inoculant from 0.5 to 0.2% increased the tool life 100%. Inoculation test castings were also poured in a class 40 gray iron; laboratory analysis is currently underway. Exploratory studies were conducted to determine if tool force could be used to predict tool life: torque and feed forces were found to correlate with machinability.

  20. A study on controlled cooling process for making bainitic ductile iron

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    In the present research, TTT curve of bainitic ductile iron under the condition of controlled cooling was generated. The cooling rate of grinding ball and its temperature distribution were also measured at the same time. It can be concluded that the bainitic zone of TTT curve is separated from the pearlitic zone. As compared to the water-quenching condition, more even cooling rate and temperature distribution can be achieved in the controlled cooling process. The controlled cooling can keep away from pearlitic zone in the high temperature cooling stage and produce similar results to the process of traditional isothermal cooling with a low cooling rate in the low temperature cooling stage.

  1. Experimental validation of error in temperature measurements in thin walled ductile iron castings

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2007-01-01

    An experimental analysis has been performed to validate the measurement error of cooling curves measured in thin walled ductile cast iron. Specially designed thermocouples with Ø0.2 mm thermocouple wire in Ø1.6 mm ceramic tube was used for the experiments. Temperatures were measured in plates...... to a level about 20C lower than the actual temperature in the casting. Factors affecting the measurement error (oxide layer on the thermocouple wire, penetration into the ceramic tube and variation in placement of thermocouple) are discussed. Finally, it is shown how useful cooling curve may be obtained...

  2. Temperature measurement during solidification of thin wall ductile cast iron. Part 1: Theory and experiment

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2008-01-01

    Temperature measurement using thermocouples (TC’s) influence solidification of the casting, especially in thin wall castings. The problems regarding acquisition of detailed cooling curves from thin walled castings is discussed. Experiments were conducted where custom made TC’s were used to acquire...... cooing curves in thin wall ductile iron castings. The experiments show how TC’s of different design interact with the melt and how TC design and surface quality affect the results of the data acquisition. It is discussed which precautions should be taken to ensure reliable acquisition of cooling curves...

  3. Graphite nodules and local residual stresses in ductile iron: Thermo-mechanical modelingand experimental validation

    DEFF Research Database (Denmark)

    Andriollo, Tito

    this as point of departure, the present work initially focuses on finding a satisfactory description of the nodules’ thermo-elastic behavior, which is shown to be missing in the published literature, by means of micro-mechanical homogenization analyses based on a representative unit cell. These, combined...... their characteristic internal structure, composed of graphite platelets arranged into conical sectors, in an explicit manner. The resulting anisotropic model turns out to provide homogenized values for the ductile iron thermo-elastic properties at the macro-scale in excellent agreement with the experiments...

  4. Application of 3-D numerical simulation software SRIFCAST to produce ductile iron castings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on a method using numerical simulation equations and their solution schemes for liquid metal flows and heat transfer during mold filling and the solidification process of casting, 3-D numerical simulation software SRIFCAST was created. This includes enmeshment of casting; velocity and temperature fields calculation; displaying iso-temperature lines;velocity vectors and 3-D temperature fields on a Windows 9x operating system. SRIFCAST was applied to produce sound castings of automobile and diesel engines, and also to connect with microstructure simulation for ductile iron castings.

  5. Feeding Against Gravity with Spot Feeders in High Silicon Ductile Iron

    DEFF Research Database (Denmark)

    Vedel-Smith, Nikolaj Kjelgaard; Tiedje, Niels Skat

    2014-01-01

    A test pattern, with three different moduli castings was developed to investigate methods to optimise feeding of high silicon ductile cast irons. Different feeder types, modulus, and locations were investigated using both an insulating and an exothermal sleeve material. Porosities were analysed......-hill against gravity. This effect may contribute to the thermal expansion created by the exothermal reaction. It was also found that the optimum feeder size does not scale linearly with the casting modulus but that larger casting modulus requires relatively smaller modulus feeders. The thermal gradient created...

  6. Property enhancement of cast iron used for nuclear casks

    Science.gov (United States)

    Behera, R. K.; Mahto, B. P.; Dubey, J. S.; Mishra, S. C.; Sen, S.

    2016-01-01

    Ductile iron (DI) is a preferred material for use in various structural, automotive, and engineering fields because of its excellent combination of strength, toughness, and ductility. In the current investigation, we elucidate the relationship between the morphological and mechanical properties of DI intended for use in safety applications in the nuclear industry. DI specimens with various alloying elements were subjected to annealing and austempering heat treatment processes. A faster cooling rate appeared to increase the nodule count in austempered specimens, compensating for their nodularity value and subsequently decreasing their ductility and impact strength. The ductility and impact energy values of annealed specimens increased with increasing ferrite area fraction and nodularity, whereas an increase in the amounts of Ni and Cr resulted in an increase of hardness via solid solution strengthening. Austempered specimens were observed to be stronger than annealed specimens and failed in a somewhat brittle manner characterized by a river pattern, whereas the ductile failure mode was characterized by the presence of dimples.

  7. Property enhancement of cast iron used for nuclear casks

    Institute of Scientific and Technical Information of China (English)

    RK Behera; BP Mahto; JS Dubey; SC Mishra; S Sen

    2016-01-01

    Ductile iron (DI) is a preferred material for use in various structural, automotive, and engineering fields because of its excellent combination of strength, toughness, and ductility. In the current investigation, we elucidate the relationship between the morphological and mechanical properties of DI intended for use in safety applications in the nuclear industry. DI specimens with various alloying elements were subjected to annealing and austempering heat treatment processes. A faster cooling rate appeared to increase the nodule count in austempered specimens, compensating for their nodularity value and subsequently decreasing their ductility and impact strength. The ductility and impact energy values of annealed specimens increased with increasing ferrite area fraction and nodularity, whereas an increase in the amounts of Ni and Cr resulted in an increase of hardness via solid solution strengthening. Austempered specimens were observed to be stronger than an-nealed specimens and failed in a somewhat brittle manner characterized by a river pattern, whereas the ductile failure mode was character-ized by the presence of dimples.

  8. Fracture mechanics behaviour of ductile cast iron and martensitic steel at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Udoh, A.; Klenk, A.; Roos, E. [Stuttgart Univ. (Germany). MPA; Sasikala, G. [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam (India)

    2010-07-01

    Ductile cast iron is employed increasingly due to the advantages regarding foundry practice, design as well as economic advantages in the thermal machinery and power plant construction. It is employed preferably where higher toughness is required, e.g. in valves or thickwalled components of thermal or nuclear power plants. For this reason the safety and availability criteria for fracture mechanics assessment of components are necessary in addition to the conventional strength design. Alloys with silicon and molybdenum are developed for the application at higher temperatures. The increase in the thermal efficiency of fossil fired steam power plant that can be achieved by increasing the steam temperature and pressure has provided the incentive for development of the 9% chromium steels towards improved creep rupture strength. During the last twenty years, three such steels, P91 (9Cr-1Mo-VNb), E911 (9Cr-1Mo-1W-V-Nb) and P92 (9Cr-0,5Mo-1,8W-V-Nb), have been developed for commercial production. For application in piping systems and boiler construction sufficient reliable information concerning the long-term behaviour are necessary as well as knowledge about fracture mechanical behaviour in order to ensure integrity of components. Different methods to characterize fracture behaviour of ductile cast iron and martensitic steel at elevated temperature have been employed. The RBR method is a novel and simple method developed at IGCAR for characterizing the ductile fracture behaviour of materials from tensile tests of cylindrical specimens. Using the data evaluated at both institutes, a fracture mechanics characterisation by determining crack initiation and crack resistance by J{sub R}-curves and RBR parameters is presented. (orig.)

  9. Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    G.S. Cho; K.H. Choe; K.W. Lee; A.Ikenaga

    2007-01-01

    The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility.Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. Hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits Iow strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added. the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries.

  10. Application of Differential Scanning Calorimetry (DSC in study of phase transformations in ductile iron

    Directory of Open Access Journals (Sweden)

    R. Przeliorz

    2010-04-01

    Full Text Available The effect of heating rate on phase transformations to austenite range in ductile iron of the EN-GJS-450-10 grade was investigated. For studies of phase transformations, the technique of differential scanning calorimetry (DSC was used. Microstructure was examined by optical microscopy. The calorimetric examinations have proved that on heating three transformations occur in this grade of ductile iron, viz. magnetic transformation at the Curie temperature, pearlite→austenite transformation and ferrite→austenite transformation. An increase in the heating rate shifts the pearlite→austenite and ferrite→austenite transformations to higher temperature range. At the heating rate of 5 and 15°C/min, local extrema have been observed to occur: for pearlite→austenite transformation at 784°C and 795°C, respectively, and for ferrite→austenite transformation at 805°C and 821°C, respectively. The Curie temperature of magnetic transformation was extrapolated to a value of 740°C. Each transformation is related with a specific thermal effect. The highest value of enthalpy is accompanying the ferrite→austenite transformation, the lowest occurs in the case of pearlite→austenite transformation.

  11. USING HIGH Mg-CONTENT CORED-WIRE TO SPHEROIDIZE AND DESULPHURIZE DUCTILE IRON MELT IN INDUSTRIAL EXPERIMENTS

    Institute of Scientific and Technical Information of China (English)

    R.Z. Wu; B.D. Sun; H.J. Ni; Y.B. Wu; H.S. Wu; J.G. Ge

    2004-01-01

    40% Mg-content cored-wire was used to desulphurize and spheroidize ductile iron melt in industrial experiments. The optimal feeding speed and suitable treatment temperature were determined in the experiments. And cored-wire method and pouring method were compared.Conclusions have been drawn that, under these conditions in the experiments, the optimal feeding speed is 15m/min, treatment temperature should be as low as possible, 1400-1450℃ generally; and cored-wire method can act more effective in ductile iron melt desulphurization and spheroid than pouring method.

  12. Statistical study to determine the effect of carbon, silicon, nickel and other alloying elements on the mechanical properties of as-cast ferritic ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Lacaze, J.; Sertucha, J.; Larranaga, P.; Suarez, R.

    2016-10-01

    There is a great interest in fully ferritic ductile irons due to their structural homogeneity, remarkable ductility and good response when machining. On the other hand the wide variety of raw materials available in foundry plants becomes a problem when controlling the chemical composition of the manufactured alloys. The present work shows a statistical study about the effect of different C, Si, Ni contents and other minor elements on structural and mechanical properties of a group of ferritic ductile iron alloys. A set of equations are finally presented to predict room temperature mechanical properties of ferritic ductile irons by means of their chemical composition and pearlite content. (Author)

  13. Corrosion Inhibiting Mechanism of Nitrite Ion on the Passivation of Carbon Steel and Ductile Cast Iron for Nuclear Power Plants

    Directory of Open Access Journals (Sweden)

    K. T. Kim

    2015-01-01

    Full Text Available While NaNO2 addition can greatly inhibit the corrosion of carbon steel and ductile cast iron, in order to improve the similar corrosion resistance, ca. 100 times more NaNO2 addition is needed for ductile cast iron compared to carbon steel. A corrosion and inhibition mechanism is proposed whereby NO2- ion is added to oxidize. The NO2- ion can be reduced to nitrogen compounds and these compounds may be absorbed on the surface of graphite. Therefore, since nitrite ion needs to oxidize the surface of matrix and needs to passivate the galvanic corroded area and since it is absorbed on the surface of graphite, a greater amount of corrosion inhibitor needs to be added to ductile cast iron compared to carbon steel. The passive film of carbon steel and ductile cast iron, formed by NaNO2 addition showed N-type semiconductive properties and its resistance, is increased; the passive current density is thus decreased and the corrosion rate is then lowered. In addition, the film is mainly composed of iron oxide due to the oxidation by NO2- ion; however, regardless of the alloys, nitrogen compounds (not nitrite were detected at the outermost surface but were not incorporated in the inner oxide.

  14. Effects of slope plate variable and reheating on semi-solid structure of ductile cast iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change the dendritic structure to globular. In the slope plate angle of 7.5°and length of 560 mm with cooling rate of 67K·s-1 the optimum nodular graphite and solid globular particle were achieved.The results also show that by using slope plate inoculant fading can be prevented more easily since the total time of process is rather short.In addition, the semi-solid ductile cast iron prepared by inclined plate method, was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. Solid fraction at different reheating temperatures and holding time was obtained and based on these results the optimum reheating temperature range was determined.

  15. Formation mechanism of spheroidal carbide in ultra-low carbon ductile cast iron

    Directory of Open Access Journals (Sweden)

    Bin-guo Fu

    2016-09-01

    Full Text Available The formation mechanism of the spheroidal carbide in the ultra-low carbon ductile cast iron fabricated by the metal mold casting technique was systematically investigated. The results demonstrated that the spheroidal carbide belonged to eutectic carbide and crystallized in the isolated eutectic liquid phase area. The formation process of the spheroidal carbide was related to the contact and the intersection between the primary dendrite and the secondary dendrite of austenite. The oxides of magnesium, rare earths and other elements can act as heterogeneous nucleation sites for the spheroidal carbide. It was also found that the amount of the spheroidal carbide would increase with an increase in carbon content. The cooling rate has an important influence on the spheroidal carbide under the same chemical composition condition.

  16. Effects of Antimony and Wall Thickness on Graphite Morphology in Ductile Iron Castings

    Science.gov (United States)

    Glavas, Zoran; Strkalj, Anita; Maldini, Kresimir

    2016-08-01

    Effects of Sb additions on the graphite morphology of ductile iron castings in different wall thicknesses (3, 12, 25, 38, 50, 75, and 100 mm) were analyzed in this paper. In the wall thicknesses of 3, 12, and 25 mm, low contents of rare earth (RE) elements showed a beneficial effect on nodule count and nodularity. Nodularity >80 pct and a high nodule count were achieved without the addition of Sb. In the wall thicknesses of 38, 50, 75, and 100 mm, nodularity >80 pct was not achieved without the use of the chill or proper content of Sb. Excess of RE elements was neutralized with the addition of proper amount of Sb to the wall thickness. Addition of 0.01 wt pct Sb (ratio of RE/Sb = 0.34, ratio of RE/SE = 0.105) was sufficient to achieve nodularity >80 pct in the wall thicknesses of 38, 50, 75, and 100 mm.

  17. Cellular automaton modeling of ductile iron microstructure in the thin wall

    Directory of Open Access Journals (Sweden)

    A.A. Burbelko

    2011-10-01

    Full Text Available The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the solidification of the ductile iron with different carbon equivalent in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration. Solidification of the DI with different carbon equivalents was analyzed. Obtained results were compared with the solidification path calculated by CALPHAD method.

  18. Effect of Feeder Configuration on the Microstructure of Ductile Cast Iron

    DEFF Research Database (Denmark)

    Vedel-Smith, Nikolaj Kjelgaard; Tiedje, Niels Skat

    2014-01-01

    iron castings. The goal is to enable metallurgists and foundry engineers to more directly target mushy zone development to prolong the possibility to feed through this section. Keeping smaller section open for an extended period will make it possible to use fewer or smaller feeders, with reduced energy......Feeding and microstructure of a test casting rigged with different feeder combinations was studied. Castings were examined and classified by soundness and microstructure. Subsequently the casting macro- and microstructure was analyzed to study how differences in solidification and segregation...... influence the soundness of different sections of the castings. Moreover, the microstructural changes due to variations in thermal gradients are classified, and the variations in the mushy zone described. The paper discusses how solidification and segregation influence porosity and microstructure of ductile...

  19. Graphite nodule count and size distribution in thin-walled ductile cast iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2008-01-01

    Graphite nodule count and size distribution have been analysed in thin walled ductile cast iron. The 2D nodule counts have been converted into 3D nodule count by using Finite Difference Method (FDM). Particles having a diameter smaller than 5 µm should be neglected in the nodule count...... as these are inclusions and micro porosities that do not influence the solidification morphology. If there are many small graphite nodules as in thin walled castings only 3D nodule count calculated by FDM will give reliable results. 2D nodule count and 3D nodule count calculated by simple equations will give too low...... results. The 3D size distribution showed presence of primary graphite nodules in hypereutectic castings. In thin plates the nodule count is similar in eutectic and hypereutectic plates. In thicker plates the hypereutectic casting has the highest nodule count....

  20. Using Cored Wires Injection 2PE-9 Method in the Production of Ferritic Si-Mo Ductile Iron Castings

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2012-12-01

    Full Text Available The results of studies on the use of modern two cored wires injection method for production of ferritic nodular cast iron (ductile iron with use of unique implementation of drum ladle as a treatment / transport and casting ladle instead vertical treatment ladle was described. The injection of length of Ø 9mm wires, cored: in FeSi + Mg nodulariser mixture and inoculant master alloy is a treatment method which can be used to produce iron melted in coreless induction furnace. This paper describes the results and analysis of using this method for optimal production of ductile iron under specific industrial conditions. It means, that length of nodulariser wire plus treatment and pouring temperatures were optimized. In this case, was taken ductile iron with material designation: EN-GJS-SiMo40-6 Grade according EN 16124:2010 E. Microstructure of great number of trials was controlled on internally used sample which has been correlated with standardsample before. The paper presents typical ferritic metallic matrix and nodular graphite. Additionally, mechanical properties were checked in some experiments. Mean values of magnesium recovery and cost of this new method from optimized process parameters werecalculated as well.

  1. Solution strengthened ferritic ductile iron ISO 1083/JS/500-10 provides superior consistent properties in hydraulic rotators

    Institute of Scientific and Technical Information of China (English)

    Dr.Richard Larker

    2009-01-01

    Consistent mechanical and machining properties are essential in many applications where ductile irons offer the most cost-effective way to produce structural parts. In the production of hydraulic rotators, dimensional tolerances are typically 20 μm to obtain designated performance.For castings where intermediate strength and ductility is required, it is common knowledge that conventional ferritic-pearlitic ductile irons such as ISO 1083/500-7 show large hardness variations. These are mainly caused by the notoriously varying pearlite content, both at different locations within a part and between parts in the same or different batches. Cooling rate variations due to different wall thickness and position in the molding box, as well as varying amounts of pearlite-stabilizing elements, all contribute to detrimental hardness variations.The obvious remedy is to avoid pearlite formation, and instead obtain the necessary mechanical properties by solution strengthening of the ferritic matrix by increasing silicon content to 3.7wt% -3.8wt%. The Swedish development in this field 1998 resulted in a national standardization as SS 140725, followed in 2004 by ISO 1083/ JS/500-10.Indexator AB decided 2005 to specify JS/500-10 for all new ductile iron parts and to convert all existing parts. Improvements include reduction by 75% in hardness variations and increase by 30% in cutting tool life, combined with consistently better mechanical properties.

  2. Fatigue behaviour of cast iron with globular graphite

    Energy Technology Data Exchange (ETDEWEB)

    Huebner, P.; Pusch, G.; Krodel, L. [Institut fuer Werkstofftechnik, TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 5, 09599 Freiberg (Germany)

    2004-07-01

    Cast iron with bainitic matrix and globular graphite, so called austempered ductile iron (ADI), allows the substitution of heat-treatable steels. The use of ADI in safety-relevant components requires knowledge of the fracture and fatigue behaviour. Cyclic stress strain behaviour and fatigue life at total strain control and random loading have been investigated at ADI (EN-GJS-1000-5) and pearlitic cast iron (EN-GJS-600-3). In addition fracture mechanic tests at cyclic loading at various stress ratios were carried out. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  3. Review of current research and application of ductile cast iron quality monitoring technologies in Chinese foundry industry

    Institute of Scientific and Technical Information of China (English)

    Da-yong Li; Zhen-yu Xu; Xu-liang Ma; De-quan Shi

    2015-01-01

    There is a long history of studying and making use of ductile cast iron in China. Over the years, the foundrymen in China have carried out a lot of valuable research and development work for measuring parameters and control ing the quality in ductile cast iron production. Many methods, such as rapid metal ographic phase, thermal analysis, eutectic expansion ratio, surface tension measurement, melt electrical resistivity, oxygen and sulfur activity measurement, ultrasonic measurement and sound frequency measurement, have been used and have played important roles in Chinese casting production in the past. These methods can be general y classiifed as liquid testing and solid testing according to the sample state. Based on the analysis of the present situation of these methods applied in the Chinese metal casting industry, the authors consider that there are two dififcult technical problems to be currently solved in monitoring ductile iron quality. One is to seek an effective method for quickly evaluating the nodularizing result through on-the-spot sample analysis before the liquid iron is poured into the mould. The other is to ifnd a nondestructive method for accurately identifying casting quality before castings are delivered.

  4. Review of current research and application of ductile cast iron quality monitoring technologies in Chinese foundry industry

    Directory of Open Access Journals (Sweden)

    Da-yong Li

    2015-07-01

    Full Text Available There is a long history of studying and making use of ductile cast iron in China. Over the years, the foundrymen in China have carried out a lot of valuable research and development work for measuring parameters and controlling the quality in ductile cast iron production. Many methods, such as rapid metallographic phase, thermal analysis, eutectic expansion ratio, surface tension measurement, melt electrical resistivity, oxygen and sulfur activity measurement, ultrasonic measurement and sound frequency measurement, have been used and have played important roles in Chinese casting production in the past. These methods can be generally classified as liquid testing and solid testing according to the sample state. Based on the analysis of the present situation of these methods applied in the Chinese metal casting industry, the authors consider that there are two difficult technical problems to be currently solved in monitoring ductile iron quality. One is to seek an effective method for quickly evaluating the nodularizing result through on-the-spot sample analysis before the liquid iron is poured into the mould. The other is to find a nondestructive method for accurately identifying casting quality before castings are delivered.

  5. New Mechanism on Synergistic Effect of Nitrite and Triethanolamine Addition on the Corrosion of Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    K. T. Kim

    2016-01-01

    Full Text Available In general, we compared the different inhibition mechanisms of organic inhibitor with that of anodic inhibitor. When triethanolamine or nitrite was added separately to tap water for inhibiting the corrosion of ductile cast iron, large amounts of inhibitor were needed. This is because the corrosion inhibitors had to overcome the galvanic corrosion that occurs between graphite and matrix. In this work, we investigated the corrosion of ductile cast iron in tap water with/without inhibitors. The corrosion rate was measured using chemical immersion test and electrochemical methods, including anodic polarization test. The inhibited surface was analyzed using EPMA and XPS. Test solutions were analyzed by performing FT-IR measurement. When triethanolamine and nitrite coexisted in tap water, synergistic effect built up, and the inhibition effect was ca. 30 times more effective than witnessed with single addition. This work focused on the synergistic effect brought about by nitrite and triethanolamine and its novel mechanism was also proposed.

  6. Foundry technology and its applications of ductile iron castings produced by water-cooled copper alloy mold

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The high efficiency mechanized foundry technology of castings produced by using water-cooled copper alloy permanent mold has been systematically studied. Through the researching a Cu-Cr-Mg alloy with high conductivity and good combined mechanical properties used for making permanent mold was developed, and the basic design principles of the water-cooled permanent mold along with the control-range of relevant foundry processing parameters were also established.A cast production line equipped with water-cooled copper alloy mold was designed and fabricated for production of ductile iron automobile gear castings. This production line can consistently make automobile gear castings in QT500-15 and QT600-5 (Chinese Standard) grades of ductile iron with up to 95 % casting success rate.

  7. A micro-mechanical analysis of thermo-elastic properties and local residual stresses in ductile iron based on a new anisotropic model for the graphite nodules

    Science.gov (United States)

    Andriollo, Tito; Thorborg, Jesper; Tiedje, Niels; Hattel, Jesper

    2016-06-01

    In this paper, the thermo-elastic behavior of the graphite nodules contained in ductile iron is derived on the basis of recent transmission electron microscopy investigations of their real internal structure. The proposed model is initially validated by performing a finite element homogenization analysis to verify its consistency with the room-temperature elastic properties of ductile iron measured at the macro scale. Subsequently, it is used to investigate the formation of local residual stresses around the graphite particles by simulating the manufacturing process of a typical ferritic ductile iron grade, and the results are compared with preliminary measurements using synchrotron x-rays. Finally, the obtained accurate description of the stress & strain field at the micro scale is used to shed light on common failure modes reported for the nodules and on some peculiar properties observed in ductile iron at both micro and macro scale.

  8. Kinetic study of austenite formation during continuous heating of unalloyed ductile iron

    Institute of Scientific and Technical Information of China (English)

    Octavio Vzquez-Gmez; Jos Antonio Barrera-Godnez; Hctor Javier Vergara-Hernndez

    2015-01-01

    The austenite formation kinetics in unalloyed cast ductile iron was studied on the basis of dilatometry measurements, and Avrami’s equation was used to estimate the material’s kinetic parameters. A continuous heating transformation diagram was constructed us-ing heating rates in the range of 0.06 to 0.83°C⋅s−1. As the heating rate was augmented, the critical temperatures, c1A and Aα, as well as the intercritical range, which was evaluated as the difference between the critical temperatures, α c1Δ T =A −A , increased. At a low heating rate, the kinetics of austenite formation was slow as a consequence of the iron’s silicon content. The effect of heating rate on k and n, the kinetic parameters of Avrami’s equation, was also determined. Parameter n, which is associated with nucleation sites and growth geometry, de-creased with an increase in heating rate. In addition, parameter k increased with the increase of heating rate, suggesting that the nucleation and growth rates are carbon-and silicon-diffusion controlled during austenite formation under continuous heating.

  9. Quantitative Analysis of Ductile Iron Microstructure – A Comparison of Selected Methods for Assessment

    Directory of Open Access Journals (Sweden)

    B. Mrzygłód

    2013-07-01

    Full Text Available Stereological description of dispersed microstructure is not an easy task and remains the subject of continuous research. In its practical aspect, a correct stereological description of this type of structure is essential for the analysis of processes of coagulation and spheroidisation, or for studies of relationships between structure and properties. One of the most frequently used methods for an estimation of the density Nv and size distribution of particles is the Scheil - Schwartz - Saltykov method. In this article, the authors present selected methods for quantitative assessment of ductile iron microstructure, i.e. the Scheil - Schwartz - Saltykov method, which allows a quantitative description of three-dimensional sets of solids using measurements and counts performed on two-dimensional cross-sections of these sets (microsections and quantitative description of three-dimensional sets of solids by X-ray computed microtomography, which is an interesting alternative for structural studies compared to traditional methods of microstructure imaging since, as a result, the analysis provides a three-dimensional imaging of microstructures examined.

  10. A visual approach to efficient analysis and quantification of ductile iron and reinforced sprayed concrete.

    Science.gov (United States)

    Fritz, Laura; Hadwiger, Markus; Geier, Georg; Pittino, Gerhard; Gröller, M Eduard

    2009-01-01

    This paper describes advanced volume visualization and quantification for applications in non-destructive testing (NDT), which results in novel and highly effective interactive workflows for NDT practitioners. We employ a visual approach to explore and quantify the features of interest, based on transfer functions in the parameter spaces of specific application scenarios. Examples are the orientations of fibres or the roundness of particles. The applicability and effectiveness of our approach is illustrated using two specific scenarios of high practical relevance. First, we discuss the analysis of Steel Fibre Reinforced Sprayed Concrete (SFRSpC). We investigate the orientations of the enclosed steel fibres and their distribution, depending on the concrete's application direction. This is a crucial step in assessing the material's behavior under mechanical stress, which is still in its infancy and therefore a hot topic in the building industry. The second application scenario is the designation of the microstructure of ductile cast irons with respect to the contained graphite. This corresponds to the requirements of the ISO standard 945-1, which deals with 2D metallographic samples. We illustrate how the necessary analysis steps can be carried out much more efficiently using our system for 3D volumes. Overall, we show that a visual approach with custom transfer functions in specific application domains offers significant benefits and has the potential of greatly improving and optimizing the workflows of domain scientists and engineers.

  11. Relationship between cooling rate and microsegregation in bottom-chilled directionally solidified ductile irons

    Directory of Open Access Journals (Sweden)

    Chang W.S.

    2013-01-01

    Full Text Available This study explores the relationship between cooling rate and microsegregation of directionally solidified ductile iron. The unidirectional heat transfer system used in this research is made up of a copper mold kept chilled by circulating water and embedded in the bottom of Furan sand mold. Thermocouples are connected to the computer measuring system to record the cooling curves of the castings at a distance of 0, 30, 60 and 90 mm from the chilled copper mold surface. Alloys including Mn, Cr, Cu, Ni and Ti were added to the specimens. Electron microprobe analysis (EPMA was employed to examine distribution of elements between the dendrite arms and nodular graphite. Results show that unidirectional heat transfer affects directly the solidification mode and microstructure of the casting. The cooling curves reveal that local solidification time increases with increasing distance from the chilled copper mold surface. Different solidification rates with corresponding microstructure and element segregation were observed in the same unidirectionally solidified casting. Local solidification time was closely related to element segregation. The effective segregation coefficient (Keff calculated using the Scheil equation was found to vary, according to the stage of solidification. The actual segregation characteristics of complex alloys generally follow the Scheil equation.

  12. Examination of Spheroidal Graphite Growth and Austenite Solidification in Ductile Iron

    Science.gov (United States)

    Qing, Jingjing; Richards, Von L.; Van Aken, David C.

    2016-09-01

    Microstructures of a ductile iron alloy at different solidification stages were captured in quenching experiments. Etched microstructures showed that spheroidal graphite particles and austenite dendrites nucleated independently to a significant extent. Growth of the austenite dendrite engulfed the spheroidal graphite particles after first contacting the nodule and then by forming an austenite shell around the spheroidal graphite particle. Statistical analysis of the graphite size distribution was used to determine the nodule diameter when the austenite shell was completed. In addition, multiple graphite nucleation events were discerned from the graphite particle distributions. Majority of graphite growth occurred when the graphite was in contact with the austenite. Circumferential growth of curved graphene layers appeared as faceted growth fronts sweeping around the entire surface of a spheroidal graphite particle which was at the early growth stage. Mismatches between competing graphene growth fronts created gaps, which divided the spheroidal graphite particle into radially oriented conical substructures. Graphene layers continued growing in each conical substructure to further extend the size of the spheroidal graphite particle.

  13. Numerical modeling of stray current corrosion of ductile iron pipe induced by foreign cathodic protection system

    Science.gov (United States)

    Li, SeonYeob; Kim, Young-Geun

    2013-07-01

    Stray current corrosion phenomena of ductile iron pipe (DIP) located in the vicinity of cathodically protected steel pipe was assessed using the boundary element method. When all joints in DIP were electrically connected, the maximum corrosion rate was 0.005 mm/y. However, when the joints were isolated, the corrosion rate increased due to the jumping effect of stray current at isolated joints, which resulted in the increase of maximum corrosion rate to 0.87 mm/y at the isolated point. Moreover, the electrical bonding between the DIP and steel pipe could not act effectively but showed an adverse effect of collecting more cathodic protection (CP) currents into the DIP, which eventually jumped out into the soil and resulted in larger amount of stray current corrosion. Therefore it is desirable to apply control methods from the design and construction stage, which include the increase of anodebed and the pipe distance, electrical connection of DIP joints, installation of sacrificial anode at isolated joints, or the application of CP on DIP, etc.

  14. Simulation of Fluid and Inclusions Dynamics during Filtration Operations of Ductile Iron Melts Using Foam Filters

    Science.gov (United States)

    Dávila-Maldonado, O.; Adams, A.; Oliveira, L.; Alquist, B.; Morales, R. D.

    2008-12-01

    The use of ceramic foam filters in ductile iron foundries to reduce the number of inclusions that reach the casting has been widely accepted. However, the exact mechanisms contributing to foam filter effectiveness are not yet known; this limits the ability to maximize filter performance and inclusion reduction. The objective of this work is to qualify and quantify the effects of the foam filter structure on inclusion retention. This has been accomplished through the development of a three-dimensional (3-D) mathematical model, based on physical water modeling and mathematical simulations. It was found that the casting rate and inclusion density play minor roles in the capture ratio, while inclusion size is the most influent variable. One mechanism for capturing inclusions involves the direct impact of an inclusion on the web wall and its adhesion after crossing over the liquid film. Two additional mechanisms involve the entrainment of inclusions by buoyancy-lift forces into low-velocity fields and the ulterior adhesion through buoyancy effects. The second mechanism is the entrainment of inclusions into microrecirculating flows; the inclusions remain in these flows for times that exceed the mold filling time. The latter mechanism has limited intensity for inclusions approximately 30 to 100 μm in size. In order to enhance the effects of this mechanism in this range of sizes, the vorticity magnitude in the microfree shear flows in the filter’s pores must be increased, through changes in the structure geometry of this device.

  15. Ductile and Compacted Graphite Iron Casting Skin -- Evaluation, Effect on Fatigue Strength and Elimination

    Science.gov (United States)

    Boonmee, Sarum

    Compacted graphite (CG) iron features a good combination of tensile strength, impact resistance, thermal conductivity and damping capacity. This combination makes CG iron a material of choice for various applications, especially for the automobile industry. The mechanical properties of CG iron listed in the standards (i.e. ASTM) are for machined specimens. However, since most iron castings retain the original casting surface (a.k.a. casting skin), the actual performance of the part could be significantly different from that of the machined specimens. Recent studies have shown the negative effect of the casting skin, but little quantification of its effect on mechanical properties is available. Further, the understanding of its mechanism of formation is at best incomplete. In this research, the effect of the casting skin on mechanical properties in CG and ductile irons (DI) is explored. The differences in tensile and fatigue properties between as-cast and machined samples were quantified and correlated to the casting skin features. It was found that the presence of the casting skin was accountable for 9% reduction of tensile strength and up to 32% reduction of fatigue strength (for CG iron with 40% nodularity). Several mechanisms of the casting skin formation are proposed in this research. The formation of ferritic and pearlitic rims is explained by decarburizing/carburizing reactions at the mold/metal interface. Mg depletion and solidification kinetics effect were identified as the formation mechanisms of the graphite degradation. A 2-D thermal diffusion model was formulated based on Mg depletion theory. The model can be used to predict the casting skin thickness when Mg depletion is the dominant mechanism. Furthermore, using the asymmetric Fe-Gr phase diagram, some instances of casting skin formation were explained based on solidification kinetics theory. The experimental microstructural evidence and the theoretical progress were conducive to the development of

  16. Effects of Austempered Temperature on Microstructure and Properties of CADI%等温淬火温度对CADI组织及性能的影响

    Institute of Scientific and Technical Information of China (English)

    孙玉福; 张婷; 赵靖宇; 刘金庆; 吴娜; 徐栩

    2011-01-01

    In this paper, the effects of austempered temperature on the morphology of bainite,contents of retained austenite, mechanical properties and wear resistance of carbide austempered ductile iron (CADI) were researched and the impact fracture mechanism was analyzed. The samples whose as-cast microstructures composed of 75% pearlite+ferrite+10% carbide, were .austenited at 920 ℃ for 1.5 h and then austempered at 240 ℃, 280 ℃ and 320 ℃ for 2 h, respectively.The results show that with the increase of austempered temperature the morphology of bainite changes from needle to featheriness; the residual austenite content increases; the impact toughness increases and the hardness and relative wear resistance reduces. After austempering at the optimal temperature 280 ℃, the microstructure is composed of bainite, 22.33% retained austenite and 10% carbide. Its hardness is HRC 50.9, impact toughness is 32.72 J/cm2, and the relative wear resistance rises by 11% than that of the samples austempered at 320 ℃. The fracture morphology of the CADI exhibits a mixed fracture characteristic.%针对含一定碳化物等温淬火球墨铸铁(CADI),研究了等温淬火温度对贝氏体相形貌、残余奥氏体量、力学性能及耐磨性能的影响,分析了冲击断裂机理.结果表明,对于铸态组织为75%珠光体+铁素体+10%碳化物试样,经920℃×1.5 h奥氏体化后,在240℃,280℃及320℃进行等温淬火处理2h,随着等淬温度的提高,贝氏体的形貌由针状变粗至羽毛状,残余奥氏体量增加,硬度减低,冲击韧度提高,相对耐磨性降低.最佳等温淬火温度为280℃,此热处理工艺后组织为贝氏体+22.33%残余奥氏体+10%碳化物,硬度HRC 50.9,冲击韧度32.72 J/c㎡,断口呈混合断裂特征,相对耐磨性比320℃时增加11%.

  17. Thermomechanical processing and mechanical properties of hypereutectoid steels and cast irons

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.; Syn, C.K.; Sherby, O.D. (eds.)

    1998-01-01

    Recent advances in metallurgy of hypereutectoid steels and cast irons show that unique properties, such ultrahigh hardness and strength, and superplasticity, are achievable. This book focuses on the mechanical properties of hypereutectoid steels and cast irons as influenced by thermomechanical processing and microstructure. Some topics covered are: (1) Hot workability of hypereutectoid tool steels; (2) Thermomechanical processing of austempered ductile iron: An overview; (3) Mechanical behavior of ultrahigh strength, ultrahigh carbon steel wire and rod; and (4) Tensile elongation behavior of fine-grained Fe-C alloys at elevated temperatures.

  18. High-Cycle Fatigue Resistance of Si-Mo Ductile Cast Iron as Affected by Temperature and Strain Rate

    Science.gov (United States)

    Matteis, Paolo; Scavino, Giorgio; Castello, Alessandro; Firrao, Donato

    2015-09-01

    Silicon-molybdenum ductile cast irons are used to fabricate exhaust manifolds of internal combustion engines of large series cars, where the maximum pointwise temperature at full engine load may be higher than 973 K (700 °C). In this application, high-temperature oxidation and thermo-mechanical fatigue (the latter being caused by the engine start and stop and by the variation of its power output) have been the subject of several studies and are well known, whereas little attention has been devoted to the high-cycle fatigue, arising from the engine vibration. Therefore, the mechanical behavior of Si-Mo cast iron is studied here by means of stress-life fatigue tests up to 10 million cycles, at temperatures gradually increasing up to 973 K (700 °C). The mechanical characterization is completed by tensile and compressive tests and ensuing fractographic examinations; the mechanical test results are correlated with the cast iron microstructure and heat treatment.

  19. Nature of Surface Changes in Stamping Tools of Gray and Ductile Cast Iron During Gas and Plasma Nitrocarburizing

    Science.gov (United States)

    Roliński, E.; Konieczny, A.; Sharp, G.

    2009-11-01

    Two cast irons, pearlitic-ferritic gray and ferritic ductile, were plasma and gas nitrocarburized at the same temperature and for the same processing time to produce a compound zone of about 10-14 μm thick. It was demonstrated that both processes caused changes in the surface roughness of the irons, and the most dramatic increase of roughness was observed after gas nitrocarburizing of the gray cast iron. It was shown that the primary reason that the results were not the same is the difference in the nitriding mechanism. Significant penetration of the surface voids and imperfections between the graphite particles and the metallic matrix by ammonia molecules led to the formation of a locally thicker compound zone and a bulging of the metallic matrix above the surface. This phenomenon did not occur in the plasma process and as a result the surface changes were much smaller than in the gas process.

  20. Modeling of damage in ductile cast iron – The effect of including plasticity in the graphite noduless

    DEFF Research Database (Denmark)

    Andriollo, Tito; Thorborg, Jesper; Tiedje, Niels Skat

    2015-01-01

    . In contrast to previous works on the subject, the material behaviour in both matrix and nodule is assumed to be elasto-plastic, described by the classical J2-flow theory of plasticity, and damage evolution in the matrix is taken into account via Lemaitre’s isotropic model. The effects of residual stresses due...... the assumption of infinitesimal strains and plane-stress conditions. Despite the latter being a limitation with respect to full 3D models, it allows a direct comparison with experimental investigations of damage evolution on the surface of ductile cast iron components, where the stress state is biaxial in nature...

  1. A study on the corrosion and erosion behavior of electroless nickel and TiAlN/ZrN duplex coatings on ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chung-Kwei [School of Dental Technology, Taipei Medical University, Taipei 110, Taiwan (China); Hsu, Cheng-Hsun, E-mail: chhsu@ttu.edu.tw [Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China); College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Cheng, Yin-Hwa [Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China); Ou, Keng-Liang [College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Department of Mechanical Engineering, National Central University, Taoyuan 320, Taiwan (China); Lee, Sheng-Long [Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China)

    2015-01-01

    Highlights: • Electroless nickel was used as an interlayer for TiAlZrN-coated ductile iron. • The duplex coatings evidently improved corrosion resistance of ductile iron. • The duplex coated ductile iron showed a good erosion resistance. - Abstract: This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies to deposit protective coatings onto ductile iron. Polarization corrosion tests were performed in 3.5 wt.% sodium chloride, and also erosion tests were carried out by using Al{sub 2}O{sub 3} particles (∼177 μm in size and Mohr 7 scale) of about 5 g. Surface morphologies of the corroded and eroded specimens were observed separately. To further understand the coating effects on both the corrosive and erosive behavior of ductile iron, coating structure, morphology, and adhesion were analyzed using X-ray diffractormeter, scanning electron microscopy, and Rockwell-C indenter, respectively. The results showed that the EN exhibited an amorphous structure while the CAE-TiAlN/ZrN coating was a multilayered nanocrystalline. When the TiAlN/ZrN coated specimen with EN interlayer could effectively increase the adhesion strength between the CAE coating and substrate. Consequently, the combination of TiAlN/ZrN and EN delivered a better performance than did the monolithic EN or TiAlN/ZrN for both corrosion and erosion protection.

  2. Austempering of hot rolled transformation-induced plasticity steels

    Institute of Scientific and Technical Information of China (English)

    Zhuang Li; Di Wu

    2008-01-01

    Thermomechanical controlled processing (TMCP) was conducted by using a laboratory hot rolling mill. Austempering inAustempering in the salt bath after hot rolling Was investigated. The effect of isothermal holding time on mechanical properties was studied throughing of the microstructure and mechanical properties of the specimens. The mechanism of transformation-induced plasticity (TRIP) was discussed. The results show that the microstructure of these steels consists of polygonal ferrite, granular bainite, and ad TRIP occur in the hot rolled Si-Mn TRIP steels. Excellent mechanical properties were obtained for various durations at 400℃. Prolonged holdingprecipitation, which destabilized the austenite. The mechanical properties were optimal when the specimen was held for 25 min, and the tensile strength, total elongation, and strength ductility balance reached the maximum values of 776 MPa, 33%,respevtively.

  3. New progress of the manufacturing technology of ductile iron%球墨铸铁生产技术的新进展

    Institute of Scientific and Technical Information of China (English)

    曾艺成; 李克锐; 张忠仇

    2014-01-01

    The ductile iron production technology of China has made great progress in recent years . That includes that high purity pig iron , raw and auxiliary materials supply is guaranteed , modulariza-tion and inoculation process is improved .there is an new kind of excellent ductile iron that has no u-niform standard , such as silicon reinforced high strength ferrite ductile iron , ferrite ductile iron with high strength and high toughness at low temperature , high strength and high plasticity austenitic duc-tile iron and high Ni austenitic ductile Iron , and specialization of ductile iron castings production , and quality consistency and stability are improved .Now China Is in a critical period from a big country to a stronger with a basic production condition of high quality ductile iron .At the same time , the paper points out the existing problems and future development direction .%我国球墨铸铁生产技术近年来取得较大进展,包括高纯生铁在内的原辅材料商品化供应有了保障;球化、孕育处理工艺有较大改进;国内外出现了各种目前标准中没有的性能优异的新一代新牌号球铁,如硅强化高强度铁素体球铁、高强度高冲击韧性低温铁素体球铁、高强度高塑性珠光体球铁以及高镍奥氏体球铁;球铁件生产专业化程度、质量稳定性和一致性正在不断提高。我国球铁行业已具备生产高端球铁件基本条件,正处于由大变强关键时期。同时指出了存在问题和今后发展方向。

  4. The effect of oxide particles on the strength and ductility of bulk iron with a bimodal grain size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Casas, C.; Tejedor, R. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Rodríguez-baracaldo, R. [Department of Mechanical Engineering, Universidad Nacional de Colombia, Bogotá. Colombia (Colombia); Benito, J.A., E-mail: Josep.a.benito@upc.edu [Department of Materials Science and Metallurgical Engineering, EUETIB, Universitat Politècnica de Catalunya, Comte d' Urgell 187, 08036 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain); Cabrera, J.M. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain)

    2015-03-11

    The strength and ductility of bulk nanostructured and ultrafine-grained iron containing 0.39% oxygen by weight was determined by tensile tests. Samples were obtained by consolidation of milled iron powder at 500 °C. Heat treatments were designed to cover a wide range of grain sizes spanning from 100 to 2000 nm with different percentages of coarse and nanostructured grain areas, which was defined as a bimodal grain size distribution. Transmission electron microscopy was used to determine the diameter, volume fraction and location of oxides in the microstructure. The strength was analysed following two approaches. The first one was based on the strong effect of oxides and involved the use of a mixed particle-grain boundary strengthening model, and the second one was based on simple grain boundary strengthening. The mixed model underestimated the strength of nanostructured samples, whereas the simple grain boundary model worked better. However, for specimens with a bimodal grain size, the fitting of the mixed model was better. In this case, the more effective particle strengthening was related to the dispersion of oxides inside the large ferrite grains. In addition, the bimodal samples showed an acceptable combination of strength and ductility. Again, the ferrite grains containing oxides promoted strain hardening due to the increase in dislocation activity.

  5. Effect of the Linear Graphite on Austempered Austemper-Bainite Ductile Iron%线状石墨对奥-贝球铁性能影响的分析

    Institute of Scientific and Technical Information of China (English)

    张博

    2009-01-01

    @@ 板簧支座零件,选用奥-贝球铁AD11000-5,性能要求:抗拉强度≥1 000 MPa,伸长率≥5%,硬度300~360 HB;组织要求:球化级别1~3级,石墨大小5~7级,基体组织为中等或细小上贝氏体+20%~30%残余奥氏体.

  6. Influence of Austempering Temperature on Water Embrittlement Behavior of Austempered Ductile Iron%等温淬火温度对奥贝球铁水脆化行为的影响

    Institute of Scientific and Technical Information of China (English)

    蔡启舟; 魏伯康; 田中雄一

    2004-01-01

    研究了等温淬火温度对奥贝球铁(ADI)水脆化行为的影响,水附着条件下不同等温淬火温度处理的ADI均发生水脆化行为,抗拉强度和伸长率显著降低;但随着等温淬火温度升高,ADI的水脆化程度降低.高强度的ADI、淬火回火球铁和珠光体球铁均发生水脆化行为,而铁素体含量高的铸态球铁和铁素体球铁无明显的水脆化行为.

  7. Casting Principle and Research Development of Austempered Ductile Iron%奥-贝球铁的铸造原理及研究进展

    Institute of Scientific and Technical Information of China (English)

    孟丽华

    2005-01-01

    奥-贝球铁具有高强度、高韧性、良好的耐磨性、耐热性、耐蚀性以及优良的铸造性能等特点,本文中概述了奥-贝球铁的铸造原理,详细介绍了碳、硅、锰、硫、磷、钼、镍、铜、钒、铌等合金元素及热处理工艺对奥-贝球铁性能的影响.并简要介绍了第四届国际奥-贝球铁学术会议的内容,对国内外奥-贝球铁的研究及生产应用作了综述,最后展望了奥-贝球铁的应用前景.

  8. Mating Surface Microstructure of Austempered Ductile Iron Bevel Gear%奥贝球铁锥齿轮啮合表面显微组织演变

    Institute of Scientific and Technical Information of China (English)

    喻国铭; 韩辉

    2010-01-01

    利用扫描电镜测试研究了锰铜合金奥贝球铁锥齿轮啮合后齿轮表面显微组织的演变.结果表明,齿轮啮合后其表面残余奥氏体转变成马氏体组织,显著提高了齿轮的表面硬度导致其耐磨性和使用寿命提高.

  9. Heating Treatment and Application of Austempering Ductile Iron%等温淬火球墨铸铁的热处理及应用

    Institute of Scientific and Technical Information of China (English)

    李佐锋

    2007-01-01

    探索了等温淬火球墨铸铁的生产工艺,分析了原料化学成分的选择,及铸造工艺中的熔炼、球化和孕育处理、浇注温度对制取球墨铸铁的影响;在获得基体组织合理的球墨铸铁的前提下,重点分析了热处理工艺中的奥氏体化温度、等温淬火温度和时间对ADI组织及性能的影响,通过实验及分析,确定了制取理想ADI的最佳热处理工艺.

  10. Study and Application of the Unalloyed Austempered Ductile Iron Disc Harrow%非合金奥贝球铁耙片的研究与应用

    Institute of Scientific and Technical Information of China (English)

    沈大东; 金宝士; 郭继伟; 徐志军

    2002-01-01

    研究了采用非合金奥贝球铁,经二次孕育处理、等温淬火等工艺措施生产耙片.耙片材质的组织为下贝氏体、残余奥氏体和少量马氏体.经装机实际耕作考核表明,使用寿命明显高于65Mn耙片,而生产成本却大为降低,经济效益和社会效益明显.

  11. Study on the Wear Resistance of Austempered Ductile Irons%等温淬火球墨铸铁耐磨性的研究

    Institute of Scientific and Technical Information of China (English)

    刘伟; 王金华; 韩建民

    2000-01-01

    对比研究了淬火45#钢、渗碳淬火20Cr钢和5种经等温淬火的球墨铸铁在干摩擦条件下的耐磨性能.结果表明,5种等温淬火球墨铸铁的耐磨性均优于2种淬火钢,并可大大降低摩擦副的总磨损量;加入少量的Mo有助于细化和增加组织中的下贝氏体,降低磨损量;多而细小的石墨球对等温淬火球墨铸铁的耐磨性不利.

  12. 等温淬火球墨铸铁(ADI)在中国的市场机会%Market Opportunities for Austempered Ductile Iron (ADI) in China

    Institute of Scientific and Technical Information of China (English)

    John; R.Keough; 夏勇

    2007-01-01

    @@ 1 引言 目前中国的工业发展速度已超过欧洲和北美,这其中绝大部分增长得益于出口.由于人民币对美元在不断升值,未来中国的大部分工业增长将来自于国内市场.

  13. Research and Industry Development of Austempered Ductile Iron%奥贝球铁(ADI)的研究与产业发展

    Institute of Scientific and Technical Information of China (English)

    常恒毅; 朱松林; 龚文邦; 余靖; 向纲玉

    2004-01-01

    新型工程材料奥贝球铁的产品研发及应用,在不同的工况下要求各异,同时存在着工艺、设备及加工三大难题.以高韧性ADI风镐缸体的批量生产实践为例,论述了产品研发的技术关键,并提出了ADI产业化的思路.

  14. Characteristics of Austempered Ductile Iron Alloyed with Low Additions of Ni and Ca%镍、铜低合金奥贝球铁特性研究

    Institute of Scientific and Technical Information of China (English)

    Tybul.,J; Kowal.,A

    2001-01-01

    阐明了含Ni、Cu质量分数分别为1.5%和0.8%的奥贝球铁的凝固/相变和性能特点.测定了凝固过程的微分热分析曲线、膨胀仪曲线,绘制了奥氏体连续冷却转变曲线和等温转变动力学曲线,对比分析了该成分铸铁的淬透性.测定了Ni、Cu合金化奥贝球铁的常温力学性能.

  15. 等温淬火球墨铸铁(ADI)现状及发展前景%Applicaton and Devdlopment Forecast of Austempered Ductile Iron in China

    Institute of Scientific and Technical Information of China (English)

    曾艺成

    2007-01-01

    ADI是一种很好的金属结构材料,但在我国还未得到广大工程技术人员的认可,同时在产业化进程中,遇到诸多问题有待解决。去年的12月,全国铸造学会铸铁熔炼专业委员会与全国ADI技术委员会在苏州的同里湖度假村召开了“第四届全国等温淬火球铁(ADI)技术研讨会”;这次大会的主题就是:共同努力继续推进我国ADI产业化进程。

  16. Property and Application of Austempered Ductile Iron%等温淬火球铁的性能及其应用

    Institute of Scientific and Technical Information of China (English)

    潘安霞

    2004-01-01

    等温淬火球铁(ADI)是一种新兴的综合力学性能很高的工程材料,对等温淬火球铁优良的综合力学性能、高的疲劳强度和良好的摩擦磨损特性做了介绍,同时对等温淬火球墨铸铁在国、内外的应用状况进行了阐述.

  17. 奥-贝球墨铸铁在精铸件上的应用%Application of Austempered Ductile Iron in Refined Castings

    Institute of Scientific and Technical Information of China (English)

    廉峰月

    2005-01-01

    第一汽车集团公司解放系列载货车所装配的汽车前拖钩一直是锻件,直到上世纪末开发了以铸代锻的汽车前拖钩(当时采用的材质是ZG45),但以铸代锻汽车前拖钩只能满足5t以下的小吨位汽车使用。随着精铸件市场竞争越来越激烈,采用新材料、新工艺来大幅度提高铸件工艺性能,以满足大吨位载货车装车,从而全面取代锻件拖钩,成为摆在技术人员面前的首要任务。

  18. Research of austempering process of low-carbon ductile iron%低碳球铁的等温淬火工艺研究

    Institute of Scientific and Technical Information of China (English)

    李玲芳; 舒信福; 朱延东; 李玉中

    2005-01-01

    对低碳球铁的等温淬火工艺进行了研究.测定了低碳球铁件在几种不同奥氏体化时间、等温温度、等温时间下的力学性能,并对金相组织进行了分析.实验结果表明:在900℃奥氏体化40min,340℃进行30min的盐浴处理,能得到σb=1040MPa,δ=3%,ak=42J/cm2,HRC=32的较高的力学性能.

  19. Effects of Holding Temperature for Austempering on Mechanical Properties of Si-Mn TRIP Steel

    Institute of Scientific and Technical Information of China (English)

    LI Zhuang; WU Di

    2004-01-01

    A new type of high strength steel containing a significant amount of stable retained austenite was obtained by austempering immediately after intercritical annealing. This sort of low carbon steel only contains alloying elements of silicon and manganese rather than nickel and chromium. Its mechanical properties were enhanced considerably due to strain-induced martensite transformation and transformation-induced plasticity (TRIP) of retained austenite when it was strained at temperatures between Ms and Md, because retained austenite was moderately stabilized due to carbon enrichment by austempering. Austempering was carried out at different temperatures and 400 ℃ was found to be optimal. Tensile strength, total elongation and strength-ductility balance reached the maximum values and the product of tensile strength and total elongation exceeded 30 135 MPa % when the TRIP steel was held at 400 ℃ and strained at 350 ℃.

  20. Effect of Slope Plate Variable and Reheating on the Semi-Solid Structure of Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming is a promising production method for a wide range of metal alloys. In spite of many applications for semi-solid processed light alloys, few works have reported on the semi-solid processing of iron and steel. In this research, an inclined plate was used to change the dendritic structure of iron to globular. The effects of the length and slope of the plate on the casting structure were examined. The results show that the process effectively changes the dendritic structure to globular. A sloped plate angle of 7.5° and length of 560 mm with a cooling rate of 67 K·s-1 gave the optimum graphite nodu-larity and solid particle globularity. The results also show that the sloped plate more easily prevents inocu-lant fading since the total time processing is rather short. In addition the semi-solid ductile cast iron prepared using the inclined plate method was reheated to examine the effect of reheating conditions on the micro-structure and coarsening kinetics of the alloy. The solid fractions at different reheating temperatures and holding times were used to find the optimum reheating temperature range.

  1. A micro-mechanical analysis of thermo-elastic properties and local residual stresses in ductile iron based on a new anisotropic model for the graphite nodules

    DEFF Research Database (Denmark)

    Andriollo, Tito; Thorborg, Jesper; Tiedje, Niels Skat;

    2016-01-01

    In this paper, the thermo-elastic behavior of the graphite nodules contained in ductile iron is derived on the basis of recent transmission electron microscopy investigations of their real internal structure. The proposed model is initially validated by performing a finite element homogenization...

  2. On the isotropic elastic constants of graphite nodules in ductile cast iron: Analytical and numerical micromechanical investigations

    DEFF Research Database (Denmark)

    Andriollo, Tito; Hattel, Jesper

    2016-01-01

    particle strength. It is shown that if the nodule internal structure is considered, the traditional isotropy assumption leads to the definition of a domain of admissible values for the effective elastic constants. However, micromechanical calculations indicate that values within the domain do not provide....... In the present paper, the nodules’ elastic properties are thoroughly investigated by means of both analytical and numerical techniques. The analysis takes into account the influence of several non-linear phenomena, as local residual stresses arising during solid-state cooling, interface debonding and limited...... mesoscopic moduli in agreement with Young's modulus and Poisson's ratio recorded for common ferritic ductile iron grades. This suggests that graphite nodules may not be considered isotropic at the microscopic scale, at least from a mechanical viewpoint....

  3. Effects of Ceramic Fibre Insulation Thickness on Skin Formation and Nodule Characteristics of Thin Wall Ductile Iron Casting

    Science.gov (United States)

    Dhaneswara, D.; Suharno, B.; Nugraha, N. D.; Ariobimo, R. D. S.; Sofyan, N.

    2017-02-01

    Skin formation has become one of the problems in the thin wall ductile iron casting because it will reduce the mechanical properties of the materials. One of the solutions to reduce this skin formation is by using heat insulator to control the cooling rate. One of the insulators used for this purpose is ceramic fibre. In this research, the thickness of the ceramic fibre heat insulator used in the mould was varied, i.e. 50 mm on one side and 37.5 mm on the other side (A), no heat insulator (B), and 37.5 mm on both sides (C). After the casting process, the results were characterized in terms of metallography by using scanning electron microscope (SEM) and tensile test for mechanical properties. The results showed that the skin thickness formed in A is 34.21 μm, 23.38 μm in B, and 27.78 μm in C. The nodule count in A is 541.98 nodule/mm2 (84.7%) with an average diameter of 15.14 μm, 590 nodule/mm2 (86.7%) with an average diameter of 13.18 μm in B, and 549.73 nodule/mm2 (87.2%) with an average diameter of 13.95 μm in C. The average ultimate tensile strength for A was 399 MPa, B was 314 MPa, and C was 415 MPa. Microstructural examination under SEM showed that the materials have a ductile fracture with matrix full of ferrite.

  4. Testing of heating and cooling process of ADI cast iron with use of ATND method

    Directory of Open Access Journals (Sweden)

    A. Białobrzeski

    2008-10-01

    Full Text Available ADI (Austempered Ductile Iron cast iron, owing to its unique combination of high tensile strength and abrasion resistance with very goodplasticity, founds implementation in many branches of industry as a substitute of alloy cast steel and carburized or heat treated steels. Inspite of its solid position among producers and recipients of castings, there are still undertaken studies aimed at perfection of its propertiesand recognition of mechanisms enabling obtaining such properties.The paper presents implementation of thermal-voltage-derivative (ATND method to registration of heating and cooling course of ADIcast iron with EN-GJS-1200-2 grade. ADI cast iron with EN-GJS-1200-2 grade underwent the study. Heat treatment of the cast iron wasperformed in Foundry Institute with use of LT ADI-350/1000 processing line. Results obtained from the testing illustrate in graphic formregistered heating and cooling curves of investigated cast irons obtained with use of the ATND method.

  5. Standard test method for determining nodularity and nodule count in ductile iron using image analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method is used to determine the percent nodularity and the nodule count per unit area (that is, number of nodules per mm2) using a light microscopical image of graphite in nodular cast iron. Images generated by other devices, such as a scanning electron microscope, are not specifically addressed, but can be utilized if the system is calibrated in both x and y directions. 1.2 Measurement of secondary or temper carbon in other types of cast iron, for example, malleable cast iron or in graphitic tool steels, is not specifically included in this standard because of the different graphite shapes and sizes inherent to such grades 1.3 This standard deals only with the recommended test method and nothing in it should be construed as defining or establishing limits of acceptability or fitness for purpose of the material tested. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address al...

  6. 推进式套头砂芯在球铁管件生产中的应用%Socket Core of Ductile Iron Pipe Fittings

    Institute of Scientific and Technical Information of China (English)

    陈剑平

    2001-01-01

    介绍了采用组合砂芯的工艺方法生产球铁管件,以及制造此类砂芯的简易射芯机。%The production of ductile iron pipe fittings by using united assembly core has been briefly introduced in this paper.The peper also discussed the design methods and techniques of those shell core and the equipment.

  7. Replacement of a defective ductile iron gas pipeline with d 500 PE 100 pipes; Austausch einer defekten GGG-Gasleitung durch PE 100-Rohre d 500

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Robert [FRIATEC Aktiengesellschaft, Mannheim (Germany)

    2010-05-15

    A 600 m long ductile cast-iron pipeline has been renewed safely, reliably and in record time in the center of the spa town of Bad Pyrmont. Following decades of positive experience, the local municipal utility placed its faith in PE 100 pipe material and resistance welding - a time-saving method of joining PE pipes which is also cost-efficient for large dimensions. (orig.)

  8. Mechanical and Tribological Properties of HVOF-Sprayed (Cr3C2-NiCr+Ni) Composite Coating on Ductile Cast Iron

    Science.gov (United States)

    Ksiazek, Marzanna; Boron, Lukasz; Radecka, Marta; Richert, Maria; Tchorz, Adam

    2016-08-01

    The aim of the investigations was to compare the microstructure, mechanical, and wear properties of Cr3C2-NiCr+Ni and Cr3C2-NiCr coatings deposited by HVOF technique (the high-velocity oxygen fuel spray process) on ductile cast iron. The effect of nickel particles added to the chromium carbide coating on mechanical and wear behavior in the system of Cr 3 C 2 -NiCr+Ni/ductile cast iron was analyzed in order to improve the lifetime of coated materials. The structure with particular emphasis of characteristic of the interface in the system of composite coating (Cr 3 C 2 -NiCr+Ni)/ductile cast iron was studied using the optical, scanning, and transmission electron microscopes, as well as the analysis of chemical and phase composition in microareas. Experimental results show that HVOF-sprayed Cr3C2-NiCr+Ni composite coating exhibits low porosity, high hardness, dense structure with large, partially molten Ni particles and very fine Cr3C2 and Cr7C3 particles embedded in NiCr alloy matrix, coming to the size of nanocrystalline. The results were discussed in reference to examination of bending strength considering cracking and delamination in the system of composite coating (Cr 3 C 2 -NiCr+Ni)/ductile cast iron as well as hardness and wear resistance of the coating. The composite structure of the coating provides the relatively good plasticity of the coating, which in turn has a positive effect on the adhesion of coating to the substrate and cohesion of the composite coating (Cr3C2-NiCr+Ni) in wear conditions.

  9. Study on Process Tolerance of Ductile Iron Based on MAGMA%基于MAGMA的球墨铸铁铸造工艺裕度分析

    Institute of Scientific and Technical Information of China (English)

    于赟; 李小平; 雷卫宁; 徐贵宝

    2012-01-01

    基于MAGMA的模拟计算,研究40 mm×200 mm×100 mm试块在不同浇注温度、砂型刚度、孕育和石墨析出的条件下缩松行为.模拟研究表明:石墨析出率和孕育效果变化对铸件缩松形成有明显影响,浇注温度变化对铸件缩松的形成影响较小,即石墨析出和孕育方式的工艺裕度小,浇注温度的工艺裕度较大,这与试验结果基本一致;MAGMA对砂型刚度对铸件缩松形成影响的模拟结果与试验不符.%The formation of porosity in 40 mm×200 mm× 100 mm ductile iron test block under the conditions of different pouring temperature, mold dilation, inoculation and graphite precipitation were investigated on the basis of MAGMA software. The results show that the variations of inoculation and graphite precipitation have distinct influence on the formation of porosity in ductile iron and the pouring temperature changes have slight influence on the formation of porosity in ductile iron, namely, the process tolerances of graphite precipitation and inoculation are small and the pouring temperature' s process tolerance is bigger, which are in accord with the experimental results. The MAGMA simulation results about effect of the mold dilation on the formation of porosity in ductile iron were inconsistent with the experimental results.

  10. Active Mg Estimation Using Thermal Analysis: A Rapid Method to Control Nodularity in Ductile Cast Iron Production

    Science.gov (United States)

    Suárez, Ramon; Sertucha, Jon; Larrañaga, Pello; Lacaze, Jacques

    2016-10-01

    Appropriate nodularity in ductile iron castings is strongly associated with the presence of high enough not combined Mg dissolved in the melt to cast. However, the residual Mg which is commonly measured for production control accounts for both dissolved Mg and Mg combined as oxides and sulfides. To account for the uncertainties associated with such a control, it is quite usual to over treat the melt with the risk of porosity appearance. A new methodology based on thermal analysis has been developed in the present work so as to estimate the amount of free Mg dissolved in the melt ready for pouring. A combination of Te mixture and a new "reactive mixture" composed of sulfur plus a commercial inoculant has been prepared for this purpose. This reactive mixture is able to transform the magnesium remaining dissolved in the melt to combined forms of this element. Experiments performed both during start of production (when Mg overtreatment is usual) and during normal mass production indicate that important variations of free Mg occur without relevant changes in residual Mg content as determined by spectrometry. The method developed in the present work has shown to be highly effective to detect those melt batches where active Mg content is not high enough for guaranteeing a correct nodularity of castings. Selection of proper active Mg thresholds and a correct inoculation process are critical to avoid "false"-negative results when using this new method.

  11. Damage Analysis of a Ferritic SiMo Ductile Cast Iron Submitted to Tension and Compression Loadings in Temperature

    Directory of Open Access Journals (Sweden)

    Isabel Hervas

    2015-12-01

    Full Text Available Tensile and compression tests were carried out on a ductile cast iron for temperatures up to 1073 K. The damage caused inside and around graphite nodules was evaluated as a function of the local equivalent plastic strain by using microstructural quantifications. The mechanical properties are strongly dependent on a temperature above 773 K. Concerning tensile behavior, an evolutional law issued from the Gurson model representing the void growth as a function of the deformation and temperature was successfully employed. It is demonstrated that the strain state and the temperature have a strong influence on the void growth function. In the case of compression tests, the temperature has a weak influence on the nodule deformation for temperatures lower than 773 K, and the mechanical behavior is driven by the viscoplastic properties of the ferrite. For higher temperatures, the mechanical properties in compression are progressively modified, since graphite nodules tend to remain spherical, and ferrite grains are severely deformed. A synthesis of the damage mechanisms is proposed in the studied range of temperature and plastic strain. It appears that the graphite nodule aspect ratio can be used as an indicator of the deformation under compression loading for temperatures ranging from room temperature to 673 K.

  12. Effects of sphere size on the microstructure and mechanical properties of ductile iron-steel hollow sphere syntactic foams

    Science.gov (United States)

    Sazegaran, Hamid; Kiani-Rashid, Ali-Reza; Khaki, Jalil Vahdati

    2016-06-01

    The effects of sphere size on the microstructural and mechanical properties of ductile iron-steel hollow sphere (DI-SHS) syntactic foams were investigated in this study. The SHSs were manufactured by fluidized-bed coating via the Fe-based commercial powder-binder suspension onto expanded polystyrene spheres (EPSs). Afterwards, the DI-SHS syntactic foams were produced via a sand-mold casting process. The microstructures of specimens were investigated by optical microscopy, scanning electron microscopy (SEM), and energy- dispersive X-ray spectroscopy (EDS). The microscopic evaluations of specimens reveal distinct regions composed of the DI matrix, SHS shells, and compatible interface. As a result, the microstructures and graphite morphologies of the DI matrix depend on sphere size. When the sphere size decreases, the area fractions of cementite and graphite phases are observed to increase and decrease, respectively. Compression tests were subsequently conducted at ambient temperature on the DI-SHS syntactic foams. The results reveal that the compression behavior of the syntactic foams is enhanced with increasing sphere size. Furthermore, the compressed specimens demonstrate that microcracks start and grow from the interface region.

  13. 提高等温淬火球铁韧性的研究与生产实践%Study and Production Practice on Increasing Ductility of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    龚文邦; 余靖; 向纲玉

    2004-01-01

    研究了高韧性等温淬火球铁的化学成分、熔炼及热处理特点.针对高韧性等温淬火球铁铸件,采用高C、Si,低Mn,严格控制P、S,采取有效的熔炼工艺并严格控制奥氏体化温度和等温淬火温度,使铸件本体力学性能平均达到抗拉强度970MPa,伸长率12.7%.

  14. Statistical study to determine the effect of carbon, silicon, nickel and other alloying elements on the mechanical properties of as-cast ferritic ductile irons

    Directory of Open Access Journals (Sweden)

    Lacaze, Jacques

    2016-06-01

    Full Text Available There is a great interest in fully ferritic ductile irons due to their structural homogeneity, remarkable ductility and good response when machining. On the other hand the wide variety of raw materials available in foundry plants becomes a problem when controlling the chemical composition of the manufactured alloys. The present work shows a statistical study about the effect of different C, Si, Ni contents and other minor elements on structural and mechanical properties of a group of ferritic ductile iron alloys. A set of equations are finally presented to predict room temperature mechanical properties of ferritic ductile irons by means of their chemical composition and pearlite content.Las fundiciones con grafito esferoidal de matriz totalmente ferrítica tienen gran interés debido a su homogeneidad estructural, alargamiento destacable y su buena respuesta frente a las operaciones de mecanizado. Por otro lado, la extensa variedad de materias primas disponibles en las plantas de fundición supone un problema a la hora de controlar de forma efectiva la composición química de las aleaciones preparadas. En este trabajo se ha realizado un estudio estadístico sobre la influencia de los diferentes contenidos de carbono, silicio, níquel y de otros elementos minoritarios sobre las características estructurales y las propiedades mecánicas de un grupo de fundiciones con grafito esferoidal y matriz ferrítica. Finalmente, se han obtenido un número de ecuaciones que permiten predecir las propiedades mecánicas a temperatura ambiente de estas fundiciones en función de su composición química y su contenido de perlita en la matriz metálica.

  15. Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

    Directory of Open Access Journals (Sweden)

    Chen Xiang

    2013-05-01

    Full Text Available In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (M represents Fe, Cr, Mn or Mo which is much like that of carbide in high chromium white cast iron. Pure ausferrite structure that consists of bainitic ferrite and retained austenite can be obtained in the matrix by austempering treatment to the cast steel. No carbides precipitate in the ausferrite structure and the morphology of borides remains almost unchanged after austempering treatments. Secondary boride particles precipitate during the course of austenitizing. The hardness and tensile strength of the austempered cast steel decrease with the increase of the austempering temperature, from 250 篊 to 400 篊. The impact toughness is 4-11 J昪m-2 at room temperature and the impact fracture fractogragh indicates that the fracture is caused by the brittle fracture of the borides.

  16. Effect of Austempering Temperature On Microstructure and Mechanical Properties of CADI%等温淬火温度对CADI组织与力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    高颂; 刘金海; 李国禄; 徐卓; 朱晨

    2008-01-01

    研究了等温淬火温度对含碳化物的等温淬火球墨铸铁(Carbidic Austempered Ductile Iron,简称CADI)的组织、硬度和冲击韧性的影响.试验结果表明:等温淬火后的组织为贝氏体、残余奥氏体和碳化物.在等温温度范围内(230-290℃),硬度随着等温淬火温度的升高呈现逐渐下降的趋势,而冲击韧性则逐渐升高;显微组织中的贝氏体针逐渐变粗.

  17. Characteristic of skin formation using zircon- and graphite-coated mold in thin wall ductile iron fabrication

    Science.gov (United States)

    Dhaneswara, Donanta; Suharno, Bambang; Nugroho, Janu Ageng; Ariobimo, Rianti Dewi S.; Sofyan, Nofrijon

    2017-03-01

    One of the problems in thin wall ductile iron (TWDI) fabrication is skin formation during the casting. The presence of this skin will decrease strength and strain of the TWDI. One of the ways to control this skin formation is to change the cooling rate during the process through a mold coating. In testing the effectiveness of skin prevention, the following variables were used for the mold coating i.e. (i) graphite: (ii) zirconium; and (iii) double layer of graphite-zirconium. After the process, the plates were characterized by non-etching, etching, tensile test, and SEM observation. The results showed that the average skin formation using graphite: 65 µm; zirconium: 13.04 µm; and double layer of graphite-zirconium: 33.25 µm. It seems that zirconium has the most effect on the skin prevention due to sulfur binding and magnesium locked, which then prevented rapid cooling resulting in less skin formation. The results also showed the number of nodules obtained in specimen with graphite: 703 nodules/mm2 with average diameter of 12.57 µm, zirconium: 798 nodules/mm2 with average diameter of 12.15 µm, and double layer of graphite-zirconium: 697 nodules/mm2 with average diameter of 11.9 µm and nodularity percentage of 82.58%, 84.53%, and 84.22%, respectively. Tensile test showed that the strength of the specimen with graphite is 301.1 MPa, with zirconium is 388.8 MPa, and with double layer of graphite-zirconium is 304 MPa. In overall, zirconium give the best performance on the skin formation prevention in TWDI fabrication.

  18. The DTIC Review: Volume 3, Number 3. Microtechnologies and Microelectronics

    Science.gov (United States)

    1997-09-01

    of Austempered Ductile Iron ," D. Bergstrom, doctoral research, Northwestern University. v Research Progress A. Problem Statement While quantitative...Materials Design project report, Northwestern University, June, 1993. 10 APPENDIX Austenite Stability and Mechanical Properties of Austempered Ductile Iron ...Abstract The stability of austenite in Austempered Ductile Iron (ADI) has been quantified by measurement of the M. a temperature, below which stress

  19. Fractomechanical Properties of As-Cast and Austempered SG Cast Iron Between -40 °C and +20 °C

    Directory of Open Access Journals (Sweden)

    V.E. Fierro

    2002-06-01

    Full Text Available The spheroidal graphite (SG cast iron fractomechanical response varies with the test temperature and with the microstructure parameters. In the present paper, we analyze this variation performing fractomechanical tests in a temperature range from -40°C to +20°C, doing also Charpy and tensile tests for material characterization. The tests were carried out on as-cast samples and heat treated samples to obtain an ADI grade 1. In both cases, we studied samples taken from two well differentiated "Y" block sizes. The results obtained show that, for the chemical composition analyzed, both castings have a fractomechanical response decrease as the temperature diminishes. Besides, the block size enlargement produce a deterioration of the mechanical properties (the fracture toughness, mainly, for both castings.

  20. Effects of Laser Shocking on the Surface Properties of Ductile Iron%激光冲击对球墨铸铁表面性能的影响

    Institute of Scientific and Technical Information of China (English)

    周建忠; 张永康; 杨继昌; 於自岚

    2001-01-01

    Selecting laser shocking parameters with the application of artificial neural networks theory,the high power density, neodymium -glass laser is used to laser shock process ductile iron QT450 - 10. The microhardness was measured and the microstructure of LSP area were examined with scanning electron microscope (SEM). The results show that the surface properties of ductile iron QT450 - 10 are improved remarkably after LSP treating. The average microhardness of the LSP area is increased by 34. 56~53.02 percent with the increasing of laser shock times (1~4),and the depth of hardened layer is about 0. 31~1.47mm%应用人工神经网络理论,合理选择激光冲击参数,对球墨铸铁QT450-10进行了激光冲击试验,并用扫描电镜和数显硬度仪等进行了分析。结果表明:激光冲击使球墨铸铁的表面性能得到明显改善,冲击区表面的平均硬度随冲击次数(1~4)的增加分别增加了34.56%~53.02%,硬化层深约为0.31mm~l 47mm。

  1. Effect of electroless nickel interlayer on wear behavior of CrN/ZrN multilayer films on Cu-alloyed ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chung-Kwei [School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei, 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei, 110, Taiwan (China); Hsu, Cheng-Hsun, E-mail: chhsu@ttu.edu.tw [Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei, 110, Taiwan (China); Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China); Kung, Shu-Chi [Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China)

    2013-11-01

    This study utilized electroless nickel as an interlayer, then coated nanoscale CrN/ZrN multilayer on Cu-alloyed ductile iron through cathodic arc deposition method. Morphology and structure of the coatings were analyzed by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and transmission electron microscopy (TEM). Moreover, Rockwell-C indentation, nanoindention, and ball-on-disk wear tests were all carried out to explore the properties of the coatings consisting of adhesion, hardness, elastic modulus, friction coefficient, and wear rate, respectively. The results showed that electroless nickel had a major amorphous phase while the CrN/ZrN multilayer coatings exhibited alternate nanocrystalline CrN and ZrN phases. Compared with single coating of electroless nickel or CrN/ZrN, the CrN/ZrN multilayer coatings with an electroless nickel interlayer exhibited higher hardness (31.1 GPa) and elastic modulus (256.4 GPa). Consequently, the ductile iron with the duplex coatings could be available to reduce both the friction coefficient and wear rate.

  2. An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Cárcel-Carrasco

    2016-11-01

    Full Text Available This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

  3. Casting Method Design of Heavy Ductile Iron Castings%大型球铁件的铸造工艺设计

    Institute of Scientific and Technical Information of China (English)

    李润生

    2011-01-01

    The main casting method design principles of heavy ductile iron castings were introduced: putting the faces to be machined downwards; adopting single parting line as possible; adopting bottom gating system; pouring simultaneously from two ends for castings with large length, and using stop plug type pouring basin for the heavy and important castings; setting open risers on the top of castings; full utilizing graphitization expansion to compensate contraction. Some practical examples were showed to explain the principles and characteristics of various casting methods suitable to heavy ductile iron castings, as well as their gating system design, riser design and chill usage.%介绍大型球铁件铸造工艺设计的主要原则为:加工面向下;尽量采用一个分型面;采用底注;长度大的铸件采用两端同时浇注,重大件采用拔塞浇包浇注;铸件顶部设置明冒口;充分利用石墨化膨胀补缩.用具体实例说明适合于大型球铁铸件的各种铸造工艺原理和特点,以及浇注系统设计、冒口设计和冷铁使用的要点.

  4. 高镍奥氏体球墨铸铁涡壳的开发%Development of High-Ni Austenitic Ductile Iron Turbine Housing

    Institute of Scientific and Technical Information of China (English)

    高顺; 程凤军; 史朝龙; 莫俊超; 宋彦丞

    2013-01-01

    针对D-3.5和D-5S两种材质的高镍奥氏体球铁涡壳进行了试验研究,认为奥氏体枝晶发达才是高镍球铁出现碎块状石墨和显微缩松难以消除的根本原因.通过MAGMA模拟软件进行了铸造工艺模拟分析,优化了铸造工艺,缩短了开发周期,降低了成本.采用长效的Si-Ba和Si-Sr孕育剂的多次孕育,并加入微量的Sn和Sb元素,同时严格控制化学成分、出铁温度等关键参数,解决了球化不稳定、碎块石墨和显微缩松等问题,成功完成了高镍奥氏体球铁涡壳的开发,掌握了高镍奥氏体球铁的批量生产技术.%Two kinds of high nickel austenite ductile iron (D-3.5 and D-5S) turbocharger housing were researched, and a large number of austenitic dendrites were deem to the basic reason of chunky graphite and porosity. By simulation of casting process with the MAGMA software, the casting process was optimized; development cycle and the cost were reduced. Using long-acting nucleating agent such as Si-Ba and Si-Sr, adding trace of Sn and Sb element, and strictly controlling the key parameters of the chemical composition, the tapping temperature and the pouring temperature, etc., we solved the problems of the spheroidizing instability, chunky graphite and porosity, so successfully completed the development of the austenite ductile iron turbocharger housing and mastered the batch production technology of the high nickel austenite ductile iron.

  5. Mechanical milling of a nano structured ductile iron powder under dry, wet and cryogenic atmospheres; Proceso de molturacion mecanica en medio seco, humedo y criogenico de polvo de hierro ductil nanoestructurado

    Energy Technology Data Exchange (ETDEWEB)

    Cinca, N.; Hurtado, E.; Cano, I. G.; Guilemany, J. M.

    2011-07-01

    The main objective of this study, is to obtain an effective particle and grain size reduction of a nano structured iron powder by mechanical milling under different milling media. One of the main challenges in this study is to work with this material of great ductility.The variables of the study to be optimized have been the following: speed of rotation, powder to ball ratio (PBR) and the percentage of control agent to induce an effective powder fracturing in front of cold welding. The powder has been characterized by a Laser Diffraction Particle Size Analyser, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and, X-ray diffraction.Through the comparative study, it is found that operating under dry milling conditions: there is a more effective particle size reduction of 43 % and grain size reduction of 62 %. In wet conditions has been reduced the amount of oxide, as well as to obtain a more homogenous distribution of the resulting powder. The results under cryogenic media is presented as promising. (Author) 15 refs.

  6. Optimization of Master Alloy Amount and Gating System Design for Ductile Cast Iron Obtain in Lost Foam Process

    OpenAIRE

    Just, P.; R. Kaczorowski; T. Pacyniak

    2013-01-01

    The paper presents the optimization of master alloy amount for the high nodular graphite yield (80-90%) in cast iron obtain in lost foam process. The influence of the gating system configuration and the shape of the reaction chamber, the degree of spheroidisation cast iron was examined. Research has shown that the, optimal of master alloy amount of 1.5% by mass on casting iron. The degree of spheroidisation is also influenced by the gating system configuration. The best spheroidisation effect...

  7. Optimization of Master Alloy Amount and Gating System Design for Ductile Cast Iron Obtain in Lost Foam Process

    Directory of Open Access Journals (Sweden)

    P. Just

    2013-07-01

    Full Text Available The paper presents the optimization of master alloy amount for the high nodular graphite yield (80-90% in cast iron obtain in lost foam process. The influence of the gating system configuration and the shape of the reaction chamber, the degree of spheroidisation cast iron was examined. Research has shown that the, optimal of master alloy amount of 1.5% by mass on casting iron. The degree of spheroidisation is also influenced by the gating system configuration. The best spheroidisation effect was obtained for liquid cast iron was fed into the reaction chamber from the bottom and discharged from the top.

  8. Effects of slope plate variable and reheating on semi-solid structure of reheating on semi-solid structure of ductile cast iron

    Directory of Open Access Journals (Sweden)

    M. Nili-Ahmadabadi

    2008-02-01

    Full Text Available Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change the dendritic structure to globular. In the slope plate angle of 7.5° and length of 560 mm with cooling rate of 67Ks-1 the optimum nodular graphite and solid globular particle were achieved.The results also show that by using slope plate inoculant fading can be prevented more easily since the total time of process is rather short. In addition, the semi-solid ductile cast iron prepared by inclined plate method, was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. Solid fraction at different reheating temperatures and holding time was obtained and based on these results the optimum reheating temperature range was determined.

  9. Corrosion Failure Analysis of Ductile Iron Potable Water Pipeline%球墨铸铁饮用水管道腐蚀失效分析

    Institute of Scientific and Technical Information of China (English)

    乔培鹏; 刘飞华; 赵万祥

    2011-01-01

    The corrosion failure behavior of ductile iron potable water,pipeline in a nuclear power plant was investigated by surface analysis method, X-ray diffraction and microbial technology. The results showed that tubercles caused by microbiologically influenced corrosion led to the pipeline failure directly. The local oxygen- concentration corrosion was another cause for accelerating the corrosion rate.%采用表面分析法、X射线衍射和微生物技术,综合研究了核电厂球墨铸铁材料饮用水管线的腐蚀失效行为。结果表明,微生物腐蚀引起的腐蚀瘤是导致管线失效的直接原因,局部氧浓差腐蚀起到了一定的加速作用。

  10. 离心复合大断面球墨铸铁轧辊的制造%Heavy Compound Ductile Iron Work Roller Manufacturing by Centrifugal Casting

    Institute of Scientific and Technical Information of China (English)

    白云龙

    2001-01-01

    The main problems of heavy compound ductile iron work roller in centrifugal casting were analyzed. The technique sketch was designed based on these problems. Some preventive measures for all kinds of possible defects were given. A qualified compound roller was manufactured successfully in practical production.%分析了大断面球墨铸铁轧辊在离心复合铸造生产中的主要难点,并针对这些难点确定工艺方案,同时针对此类轧辊可能产生的各种缺陷提出预防措施,在实际生产中成功制造出优质复合轧辊。

  11. Development of Cast Iron in China in the Past Sixty Years%六十年来我国铸铁材料的发展

    Institute of Scientific and Technical Information of China (English)

    张伯明

    2012-01-01

    我国是铸造生产大国,2010年铸件年产量已近4 000万吨,连续11年位居世界首位.铸造新材料,新技术不断得到推广和应用,铸件质量逐渐提高,我国的铸造业正在向铸造强国挺进.本文简要论述了铸铁材料的发展历程、现状以及未来发展趋势.详细介绍了我国在灰铸铁、球墨铸铁、等温淬火球墨铸铁(ADI)、蠕墨铸铁、可锻铸铁以及特种性能铸铁方面的发展及应用情况,并指出了未来的发展方向.%With the promotion and application of new foundry materials and technologies, the castings' quality has been improved gradually. This paper presents the development history, status and tendency of cast iron. Hie development and application of cast iron in China, including gray cast iron, ductile iron, austempered ductile iron, vermicular cast iron, malleable cast iron, as well as cast irons with special performance, were introduced in detail, and the development direction of cast irons was pointed out.

  12. Threading on ADI Cast Iron, Developing Tools and Conditions

    Science.gov (United States)

    Elósegui, I.; de Lacalle, L. N. López

    2011-01-01

    The present work is focussed on the improvement of the design and performance of the taps used for making threaded holes in ADI (Austempered Ductile Iron). It is divided in two steps: a) The development of a method valid to compare the taps wear without reaching the end of their life, measuring the required torque to make one threaded hole, after having made previously a significant number of threaded holes. The tap wear causes some teeth geometrical changes, that supposes an increase in the required torque and axial force. b) The taps wear comparison method is open to apply on different PVD coated taps, AlTiN, AlCrSiN, AlTiSiN, , and to different geometries.

  13. Effects of sphere size on the microstructure and mechanical properties of ductile iron-steel hollow sphere syntactic foams

    Institute of Scientific and Technical Information of China (English)

    Hamid Sazegaran; Ali-Reza Kiani-Rashid; Jalil Vahdati Khaki

    2016-01-01

    The effects of sphere size on the microstructural and mechanical properties of ductile iron–steel hollow sphere (DI–SHS) syntactic foamswere investigated in this study. The SHSs were manufactured by fluidized-bed coating via the Fe-based commercial powder–binder suspension onto expanded polystyrene spheres (EPSs). Afterwards, the DI–SHS syntactic foams were produced via a sand-mold casting process. The microstructures of specimens were investigated by optical microscopy, scanning electron microscopy (SEM), and en-ergy-dispersive X-ray spectroscopy (EDS). The microscopic evaluations of specimens reveal distinct regions composed of the DI matrix, SHS shells, and compatible interface. As a result, the microstructures and graphite morphologies of the DI matrix depend on sphere size. When the sphere size decreases, the area fractions of cementite and graphite phases are observed to increase and decrease, respectively. Compression tests were subsequently conducted at ambient temperature on the DI–SHS syntactic foams. The results reveal that the compres-sion behavior of the syntactic foams is enhanced with increasing sphere size. Furthermore, the compressed specimens demonstrate that mi-crocracks start and grow from the interface region.

  14. 高温预处理及等温淬火工艺对含碳球墨铸铁力学性能的影响%Effects of high temperature pretreatment and austempering process on mechanical properties of CADI

    Institute of Scientific and Technical Information of China (English)

    陈传胜; 刘建升; 祖方遒

    2016-01-01

    研究了高温预处理、奥氏体化温度(Tγ)及等温淬火温度(TA)对0.5%Cr含碳化物等温淬火球墨铸铁(CADI)的韧性、硬度的影响。结果表明,高温预处理可使CADI的冲击性能提高90%以上。当硬度为51.4~55.7 HRC时,冲击吸收能量( K)可达37.7~18.3 J。高温预处理后,随着Tγ的升高,CADI的K明显提高,硬度在一定范围内略有降低;随着TA 的升高,CADI硬度逐渐降低,而K在260℃时达到最高。%Effects of high temperature pretreatment, austenitizing temperature (Tγ) and austempering temperature (TA) on toughness and hardness properties of carbidic austempered ductile iron (CADI) with 0.5%Cr were investigated.The results show that high temperature pretreatment can make the impact toughness of CADI increase more than 90%.The hardness value is 51.4-55.7 HRC corresponding to the impact absorbed energy ( K) is 37.7-18.3 J.After high temperature pretreatment, the K of CADI is significantly improved and its hardness decrease with the increase of Tγ, the hardness of CADI decreases with the increase of TA and the K achieves the best when TA is 260 ℃.

  15. An Analysis for Cause of Shrinkage near the Intake of the Ductile Iron Camshaft%球铁凸轮轴进水口产生缩孔的原因分析

    Institute of Scientific and Technical Information of China (English)

    沈保罗; 李莉; 岳昌林; 黄明俊

    2011-01-01

    The results of analysis have showed that the excessive arsenic content in the 477F-type ductile iron camshaft was the root cause of the shrinkage produced near the intake of the camshaft. The defect would be avoided with control of arsenic content less than 0.01% in ductile iron production.%分析结果表明,477F球铁凸轮轴中砷含量超标是该凸轮轴进水口附近产生缩孔的根本原因,生产中将砷含量控制在0.01%以下可以避免球铁凸轮轴产生该缺陷.

  16. A Predictive Framework for Thermomechanical Fatigue Life of High Silicon Molybdenum Ductile Cast Iron Based on Considerations of Strain Energy Dissipation

    Science.gov (United States)

    Avery, Katherine R.

    Isothermal low cycle fatigue (LCF) and anisothermal thermomechanical fatigue (TMF) tests were conducted on a high silicon molybdenum (HiSiMo) cast iron for temperatures up to 1073K. LCF and out-of-phase (OP) TMF lives were significantly reduced when the temperature was near 673K due to an embrittlement phenomenon which decreases the ductility of HiSiMo at this temperature. In this case, intergranular fracture was predominant, and magnesium was observed at the fracture surface. When the thermal cycle did not include 673K, the failure mode was predominantly transgranular, and magnesium was not present on the fracture surface. The in-phase (IP) TMF lives were unaffected when the thermal cycle included 673K, and the predominant failure mode was found to be transgranular fracture, regardless of the temperature. No magnesium was present on the IP TMF fracture surfaces. Thus, the embrittlement phenomenon was found to contribute to fatigue damage only when the temperature was near 673K and a tensile stress was present. To account for the temperature- and stress-dependence of the embrittlement phenomenon on the TMF life of HiSiMo cast iron, an original model based on the cyclic inelastic energy dissipation is proposed which accounts for temperature-dependent differences in the rate of fatigue damage accumulation in tension and compression. The proposed model has few empirical parameters. Despite the simplicity of the model, the predicted fatigue life shows good agreement with more than 130 uniaxial low cycle and thermomechanical fatigue tests, cyclic creep tests, and tests conducted at slow strain rates and with hold times. The proposed model was implemented in a multiaxial formulation and applied to the fatigue life prediction of an exhaust manifold subjected to severe thermal cycles. The simulation results show good agreement with the failure locations and number of cycles to failure observed in a component-level experiment.

  17. Trial Production of Ductile Iron Connecting Rod Used for High Speed Locomotive%高速机车用球墨铸铁连杆的试制

    Institute of Scientific and Technical Information of China (English)

    鲍玉龙; 王德军

    2012-01-01

    采用覆砂铁型铸造工艺试制了美国EMD高速机车用的球墨铸铁连杆.通过合理设计浇注系统,严格控制化学成分和浇注工艺,获得了满意的结果:(1)铸件的表面质量及尺寸精度均满足技术指标要求,球化级别达到2级;热处理后铸件本体基体组织中铁素体体积分数达94%;(2)铸件力学性能达到美国ASTM A 536-84标准,符合牌号65 -45 - 12标准要求,即抗拉强度≥448 MPa,屈服强度≥310 MPa,伸长率≥12%,-20℃低温冲击值≥12 J/cm2.%The ductile iron connecting rod used for EMD high speed locomotive imported from United States was produced in the trial way with the sand-coaled permanent mold casting process. By designing proper gating system,and by strictly controlling chemical composition, iron melting and pouring process,satisfied results were obtained: (a)Both the surface quality and dimensions met the technical requirements, and nodularity reached grade 2; and the ferrite volumetric fraction in the matrix structure of the as-heat-treated casting body reached 94% ; (b)The mechanical properties of the casting met the requirements of grade 65-45-12 specified by the US standard ASTM 536-84,i.e. tensile strength ≥448 MPa,yield strength ≥310 MPa, elongation ≥ 12%, low temperature(-20℃ ) impact toughness≥ 12 J/cm2.

  18. Ultrasonic testing of pre-turned contours for large components made of ductile iron; Ultraschallpruefung an Vordrehkonturen fuer grosse Bauteile aus Gusseisen mit Kugelgraphit

    Energy Technology Data Exchange (ETDEWEB)

    Schmitte, Till; Chichkov, Nikolai; Nemitz, Oliver; Orth, Thomas [Salzgitter Mannesmann Forschung GmbH, Duisburg (Germany); Hocks, Heinrich Jr.; Rusche, Sascha; Opalla, Dirk; Frank, Joerg [GNS Gesellschaft fuer Nuklear-Service mbH, Essen (Germany)

    2015-07-01

    In the ultrasonic testing of large, thick-walled components made of ductile iron partial acoustic paths of several meters are needed. Considered here are cylindrical components such as the body of CASTOR containers with diameters 2-3 m, a height of up to 6 m and a wall thickness of 500 mm. So far, an automated technique for this is not available, therefore such components are checked in a complex and lengthy process by manual ultrasonic testing. The development and design of the testing by means of simulations and the realization as a mobile testing device are topics of this paper. Measurements on a reference body with test reflectors in different depths are presented and discussed. [German] Bei der Ultraschall-Pruefung von grossen, dickwandigen Bauteilen aus Gusseisen mit Kugelgraphit werden teilweise Schallwege von mehreren Metern noetig. Betrachtet werden hier zylinderfoermige Bauteile, wie die Koerper von CASTOR-Behaeltern, mit Durchmessern zwischen 2 und 3 m, einer Hoehe von bis zu 6 m und Wanddicken von ca. 500 mm. Bisher ist eine automatisierte Technik hierfuer nicht verfuegbar, daher werden derartige Bauteile in einem aufwaendigen und langwierigen Prozess mittels manueller Schallung geprueft. Zur Erhoehung der Nachweissicherheit und zur Steigerung der Effizienz im Pruefablauf sollen nun senkrecht zur Achse des zylinderfoermigen Bauteils liegende unzulaessige Anzeigen im gesamten Mantelvolumen durch eine teilautomatisierte Pruefung ausgeschlossen werden. Die Entwicklung und Auslegung der Prueftechnik mittels Simulationen und die Realisierung als mobile Pruefvorrichtung sind Themen dieses Beitrags. Messungen an einem Referenzkoerper mit Testreflektoren in verschiedenen Tiefen werden vorgestellt und diskutiert.

  19. Effect of CeO{sub 2} addition on thermal shock resistance of WC–12%Co coating deposited on ductile iron by electric contact surface strengthening

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiaoben [College of Mechanical Engineering, Donghua University, Shanghai 201620 (China); College of Mechanical Engineering, Shanghai Dianji University, Shanghai 200240 (China); Zhu, Shigen, E-mail: sgzhu@dhu.edu.cn [College of Mechanical Engineering, Donghua University, Shanghai 201620 (China); Engineering Research Center of Advanced Textile Machinery, Ministry of Education, Shanghai 201620 (China)

    2015-09-15

    Highlights: • WC–Co powders with CeO{sub 2} were deposited by electric contact strengthening (ECS). • ECS is based on electric resistive heating between the electrode and work piece. • WC–Co coating with CeO{sub 2} by ECS was metallurgically bonded to the substrate. • The addition of CeO{sub 2} could refine the coating microstructure and increase the microhardness. • By the proper addition of cerium oxide, the thermal shock performance was enhanced. - Abstract: The WC–12%Co powders with different contents of CeO{sub 2} (0.1–2 wt.%) were deposited on ductile iron by electric contact surface strengthening. The coatings with and without CeO{sub 2} were examined and tested for microstructural characteristic, phase structure, microhardness and thermal shock resistance. The comparison concluded that the proper addition of CeO{sub 2} could refine the microstructure of coatings and increase the microhardness of the coatings. By the small amount addition of cerium oxide (0.5 wt.%), the solid solution strengthening effect and grain boundaries strengthening effect would delay the time of crack formation and propagation in the coatings and enhance the thermal shock performance.

  20. Chunky graphite formation in small section ductile iron castings; Formacion de grafito chunky en piezas de pequeno espesor fabricadas utilizando fundicion de hierro con grafito esferoidal

    Energy Technology Data Exchange (ETDEWEB)

    Asenjo, I.; Larranaga, P.; Sertucha, J.

    2011-07-01

    Chunky graphite is a degenerated graphite form which can be found in the thermal centre of ductile iron heavy section castings. Previous studies made on cubic blocks (300 and 180 mm in side) manufactured using alloys with fully ferritic matrix structures show that low cooling rates, excessive post-inoculation and high silicon and/or cerium contents in the melts are the most important factors that promote this kind of defect. The enhancement of these critical factors led to obtain chunky graphite in sections lower than 50 mm. Different experimental conditions have been used in order to establish the main parameters that affect this graphite malformation. The use of cutting-edge techniques in the analysis of chemical compositions has revealed that no significant differences can be found when comparing chunky areas and well-formed spheroidal graphite areas. On the other hand, it has not been possible to establish any correlation between the oxygen contents and the scale of the defect. However, it is noteworthy that the oxygen content is related to the use of magnesium or cerium as nodulized agent. (Author) 23 refs.

  1. High Integrity Castings: Proceedings of the Conference on Advances in High Integrity Castings Held in Conjunction with the 1988 World Materials Congress, Chicago, Illinois, USA, 24-30 September 1988

    Science.gov (United States)

    1988-01-01

    optimization for Austempered Ductile Iron . Although traditional SPC techniques help maintain current levels of reliability, in order to obtain "World...heat production of ADI: metal casting and treating process will be discussed. heat treating. The desired properties Austempered Ductile Iron (ADI...understood, austempered STEEL IRON ductile iron production becomes as simple and reliable as that of other YIELD STRENGTH, KSI 75 70 120 conventional steel

  2. The Use of Nitriding to Enhance Wear Resistance of Cast Irons and 4140 Steel

    Science.gov (United States)

    Yang, Zaidao

    This research is focused on using nitriding to enhance the wear resistance of austempered ductile iron (ADI), ductile iron (DI), and gray iron (GI), and 4140 steel. Three gas nitriding processes, namely "Gas nitriding + nitrogen cooled down to 800°F (Blue)", "Gas nitriding + cooled down to 300°F (Gray)", and "Gas nitriding + oil quenched (Oil)" were used for the cast irons. Three salt bath nitriding processes, namely Isonite, QP (Quench, Polish) and QPQ (Quench, Polish, Quench) were used for the 4140 steel. This study was carried out through optical metallography, roughness measurements, microhardness, and SEM. The ball-on-disc wear tests were conducted under lubricated conditions. It was found that COF for all materials in all nitrided conditions was small (<0.045). The best wear performance was seen for ADI processed using the Gray and Oil gas nitriding processes. For the 4140 steel, The surface microhardness of the ISONITE specimen was around 1400HV. QP and QPQ processes produce a surface microhardness of 2000-2200HV, which suggests that they may show improved wear behaviour compared to ISONITE- treated steels.

  3. 预退火处理对奥贝球铁力学性能的影响%Effect of Pre-annealing on Mechanical Properties of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    王从祥; 刘仙山; 龙满林

    2003-01-01

    研究了预退火处理对奥贝球铁力学性能的影响.结果表明,进行了预退火处理的奥贝球铁材料的强度、硬度有一定的降低,但其伸长率有较大幅度的提高,材料的综合力学性能得到极大的改善.

  4. Design of Automatic Production Line of Austempered Ductile Iron Grinding Balls by Coated Sand Metal Mould Casting%金属型全覆砂铸造磨球自动化生产线工艺装备设计

    Institute of Scientific and Technical Information of China (English)

    荣建忠; 关成君

    2009-01-01

    介绍了一种新型金属型等温淬火球墨铸铁(ADI)磨球全覆砂自动化生产线的工艺装备和流程,详细论述了模具、射芯机、浇铸等设备的功能特点,并提出了生产线目前存在的问题和解决方案,指出磨球自动化生产线具有广阔的市场应用前景.

  5. 铜钼合金奥贝球铁力学性能的稳定性%Stability of Mechanical Properties for 0.5Cu-0.2Mo Alloyed Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    刘生发; 徐萍; 王仲范

    2004-01-01

    研究了铜钼合金奥贝球铁力学性能的稳定性.结果表明:在95%的概率下,所研制的铜钼合金奥贝球铁达到了国外同类材料的力学性能水平;铸造缺陷、石墨形态和基体组织对奥贝球铁力学性能的稳定性产生显著影响,并相应地提出了质量控制的基本原则.

  6. 等温淬火工艺对低碳球墨铸铁组织与性能的影响%Research of Austempering Process of Low-carbon Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    李玲芳; 舒信福

    2007-01-01

    对低碳球铁的等温淬火工艺进行了研究.测定了低碳球铁件在几种不同奥氏体化时间、等温时间下的力学性能,并对金相组织进行了分析.实验结果表明:在900 ℃奥氏体化40 min,340 ℃进行30 min的盐浴处理,能得到抗拉强度σb=1 040 Mpa,延伸率δ=3%,冲击韧性αk= 42 J/cm2,硬度HRC=32的较高的力学性能.

  7. 等温热处理工艺对奥-贝球铁焊缝的影响%Effect of Isothermal Heat Treatment Process on Austempered Ductile Iron Weld

    Institute of Scientific and Technical Information of China (English)

    刘炼

    2002-01-01

    系统地研究了奥氏体化温度及保温时间、等温温度及等温时间对奥-贝球铁焊缝金属组织与力学性能的影响规律,探讨了其影响机理,并确定了最佳的等温热处理工艺。

  8. 等温淬火温度对奥贝球墨铸铁力学性能的影响%Effect of lsothermal Quenching Temperature on Mechanical Properties of Austempered Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    刘贯军; 王太轩

    2001-01-01

    研究表明,随着等温淬火温度的升高,奥贝球墨铸铁的抗拉强度和硬度均呈下降趋势,伸长率呈上升趋势,而冲击韧度则随等温淬火温度的升高先增后减,有峰值出现.

  9. Fatigue Strength of Graphite-Matrix Interface in Austempered Ductile Iron%奥氏体-贝氏体球墨铸铁中石墨与基体界面的疲劳强度

    Institute of Scientific and Technical Information of China (English)

    吴维青

    2004-01-01

    采用系统分析的方法,通过3点弯曲疲劳实验,跟踪监测了奥氏体-贝氏体球墨铸铁试样的疲劳损伤过程.实验结果表明,奥氏体-贝氏体球墨铸铁中石墨球与基体组织界面有一定的疲劳强度;在不同的疲劳载荷作用下,该处疲劳开裂的时间和程度存在差异,并对疲劳裂纹的萌生和扩展有不同的影响.

  10. Austempered Ductile Iron and Its Developing Prospect in Our Country%等温淬火球铁及其在国内开发应用前景展望

    Institute of Scientific and Technical Information of China (English)

    李可青; 杨迎东; 张喜; 杜玉柱; 张云鹏

    2004-01-01

    由于等温淬火球墨铸铁(ADI)具有优异的综合力学性能,已在工业发达国家得到了广泛应用.本文概述了ADI的等温淬火工艺和影响ADI性能的因素.在此基础上,针对国内的现实情况,展望了ADI在我国的发展趋势.

  11. Research on Microstructure and Mechanics Properties of Mn-Cu Alloyed Austempered Ductile Iron%锰钢合金奥贝球铁组织与力学性能研究

    Institute of Scientific and Technical Information of China (English)

    柳安民; 刘生发

    2010-01-01

    利用光学显微镜、扫描电镜和性能测试等手段研究了锰铜合金奥贝球铁标准试样的显微组织与力学性能.结果表明,锰铜合金奥贝球铁标准试样经等温淬火和回火后的力学性能范围为σb1007.4~1200MPa,65.2%~8.8%,HRC32~35,αk70~120J/cm2,达到了EN1564-97/EN-CJS-1000-5欧洲标准.

  12. 奥贝球铁蜗轮在阀门电动装置上的应用%Application of Austempered Ductile Iron Worm Gear in Electric Valve Actuator

    Institute of Scientific and Technical Information of China (English)

    唐涛

    2013-01-01

    分析了热处理工艺中奥氏体化温度和时间、等温淬火温度和时间对奥贝球铁性能的影响.确定了阀门驱动装置用奥贝球铁材料蜗轮的生产工艺.通过装机试验验证,研制的奥贝球铁材料蜗轮满足使用性能要求,降低了生产成本.

  13. Advance of Research on Austempered Ductile Iron Weld Metal%等温热处理获得奥-贝球铁焊缝金属研究进展

    Institute of Scientific and Technical Information of China (English)

    李凤云; 邓鹏辉

    2001-01-01

    奥-贝球铁具有优异的综合力学性能和良好的耐磨性,引起了世界广泛关注.本文重点对我国在奥-贝球铁研究中有关合金元素在铸铁焊缝中的冶金行为,奥-贝球铁的组织与力学性能,焊缝金属通过等温热处理获得奥-贝球铁组织及奥-贝球铁焊接新材料的研究进展给以介绍.

  14. 铁型覆砂铸造生产的等温淬火球墨铸铁坯件%Application of Sand-Lined Metal Mold to Production of Austempered Ductile Iron Castings

    Institute of Scientific and Technical Information of China (English)

    沈永华

    2008-01-01

    稳定、高质量的球墨铸铁件是生产等温淬火球墨铸铁(ADI)件的基础.利用铁型覆砂铸造在球铁件生产中的优势,稳定生产高质量的球铁件是可行的.列举了部分ADI曲轴、齿轮、斜楔等球铁坯件采用铁型覆砂铸造,取得了较好效果.

  15. A New Direct-Pour In-Mold (DPI) Technology for Producing Ductile and Compacted Graphite Iron Castings.

    Energy Technology Data Exchange (ETDEWEB)

    Jason Hitchings; Jay R. Hitchings

    2007-07-20

    A new "Direct Pour In-Mold" (DPI) Magnesium treatment technology has been developed that can produce both Nodular and Compacted Graphite iron. The DPI technology converts the standard horizontal runner system into a vertical one, by placing a Magnesium Ferrosilicon treatment alloy and molten metal filter into a specially designed container. The DPI container is easily placed into either vertically or horizontally parted molds, and then a base metal can be poured directly into it. The metal is treated and filtered as it passes through, and then proceeds directly into a runner or casting cavity. Various sizes of containers provide all of the necessary components required to deliver a range of weights of treated and filtered metal at accurate and consistent flow rates. The DPI containers provide energy savings over competing techniques, increased mold yields, very high Magnesium recovery, zero Magnesium fume, and no post inoculation is required. By treating the metal just prior to it entering a casting cavity many other benefits and advantages are also realized.

  16. Effects of phosphate addition on biofilm bacterial communities and water quality in annular reactors equipped with stainless steel and ductile cast iron pipes.

    Science.gov (United States)

    Jang, Hyun-Jung; Choi, Young-June; Ro, Hee-Myong; Ka, Jong-Ok

    2012-02-01

    The impact of orthophosphate addition on biofilm formation and water quality was studied in corrosion-resistant stainless steel (STS) pipe and corrosion-susceptible ductile cast iron (DCI) pipe using cultivation and culture-independent approaches. Sample coupons of DCI pipe and STS pipe were installed in annular reactors, which were operated for 9 months under hydraulic conditions similar to a domestic plumbing system. Addition of 5 mg/L of phosphate to the plumbing systems, under low residual chlorine conditions, promoted a more significant growth of biofilm and led to a greater rate reduction of disinfection by-products in DCI pipe than in STS pipe. While the level of THMs (trihalomethanes) increased under conditions of low biofilm concentration, the levels of HAAs (halo acetic acids) and CH (chloral hydrate) decreased in all cases in proportion to the amount of biofilm. It was also observed that chloroform, the main species of THM, was not readily decomposed biologically and decomposition was not proportional to the biofilm concentration; however, it was easily biodegraded after the addition of phosphate. Analysis of the 16S rDNA sequences of 102 biofilm isolates revealed that Proteobacteria (50%) was the most frequently detected phylum, followed by Firmicutes (10%) and Actinobacteria (2%), with 37% of the bacteria unclassified. Bradyrhizobium was the dominant genus on corroded DCI pipe, while Sphingomonas was predominant on non-corroded STS pipe. Methylobacterium and Afipia were detected only in the reactor without added phosphate. PCR-DGGE analysis showed that the diversity of species in biofilm tended to increase when phosphate was added regardless of the pipe material, indicating that phosphate addition upset the biological stability in the plumbing systems.

  17. Manufacturing Technology Research Needs of the Gear Industry

    Science.gov (United States)

    1987-12-31

    OF TER1S ADI Austempered Ductile Iron AGMA American Gear Manufacturers Association AGV Automatic Guided Vehicle Al Artificial Intelligence ASME...I 3 2.2.11.5 Department of Commerce. The Department of Commerce is provid- ing about half the funding for a program on austempered ductile iron (ADI... austempered ductile iron (ADI) as a gear mate- rial has developed. ADI gives a uniquely favorable performance, i.e., 3 strength and toughness, due to

  18. A Comparison of CuAlNi and Other High Damping Alloys for the Purpose of Naval Ship Silencing Applications

    Science.gov (United States)

    1989-09-01

    Austempered ductile iron has the potential for extensive use in diesel propulsion plants. In order to evaluate these materials properly, an engineering...31 AUSTEMPERED DUCTILE IRON grade one Composition Properties (weight percent) Fe Balance Tensile Strength (kel) - 125 C 3.1 - 3.8 Yield Strength...Metallurgy Branch, Code 2182, Annapolis, Maryland. 30. Forrest, R.D., " Austempered Ductile Iron for Both Strength and Toughness," Machine Design, pp

  19. 球墨铸铁飞轮壳的无冒口铸造工艺实践%Non-Riser Casting Technological Practice of Ductile Iron Flywheel-Casing

    Institute of Scientific and Technical Information of China (English)

    张春明

    2013-01-01

    对某球铁飞轮壳铸件的无冒口铸造工艺进行了分析,采用呋喃树脂自硬砂造型、控制铁液的化学成分、采用中间底注、铁液分散进入型腔的浇注方式以及四角设置出气孔等措施,使球铁飞轮壳的无冒口铸造工艺得到了实现,生产的球铁飞轮壳力学性能符合技术要求,且实现了批量生产.%The non-riser casting technological design of ductile iron flywheel-casing was analyzed, and the casting technology was achieved by no-bake sand molding, controlling composition of iron melt, pouring from bottom center of the casting and dispersing into the mould cavity, and exhausting from four holes around the casting. The mechanical properties of the ductile iron flywheel-casing made by this technology meet the technical standard, and the batch production is achieved.

  20. Effect of Austempering on Mechanical Properties of Dual Phase ADI%等温淬火工艺对双相等温淬火球墨铸铁力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    姜利坤; 刘金海; 李国禄; 王磊; 田霄楠

    2009-01-01

    对双相ADI(双相等温淬火球墨铸铁Dual Phase Austempered Ductile Iron,简称Dual Phase ADI)在不同等温温度和不同等温时间下的力学性能进行了试验.结果表明:当等温温度在250~390℃时,随着等温淬火温度的升高,双相ADI的抗拉强度减小,伸长率逐渐增大,硬度先减小后增大,冲击韧性先增大后减小.当等温时间在30~120min时,随着等温淬火时间的延长,双相ADI的抗拉强度升高,超过90min后,抗拉强度略有降低;当等温淬火时间为60min时,冲击韧性达到最大值,超过60min后,冲击韧性逐渐减小;伸长率先增大后减小;硬度逐渐增大.

  1. 奥氏体化温度对双相ADI中残余奥氏体含量的影响%Effects of austempering on residual austenite content of dual phase ADI

    Institute of Scientific and Technical Information of China (English)

    姜利坤; 刘运腾; 田长文; 赵德刚; 李卫红; 周吉学; 詹成伟

    2012-01-01

    The residual austenite has significant influence on the mechanical properties of Dual Phase Austempered Ductile Iron (ADI). We address the effects of austenitizing temperature on the content of retained austenite in ADI with X-ray method to investigate the relationship between process, organization and performance. Results show that the content of retained austenite .qradually increases with the increase of austenitizinq temperature.%残余奥氏体对双相等温淬火球墨铸铁(ADI)的力学性能影响比较显著。为了进一步了解工艺-组织-性能的关系,利用X射线法研究了奥氏体化温度对双相ADI中残余奥氏体含量的影响。结果表明随着奥氏体化温度的升高,残余奥氏体的含量逐渐增大。

  2. 球铁飞轮的铁型覆砂铸造生产及缺陷防止%Production of Ductile Iron Fly Wheel by Permanent Mold with Coated Sand and its Defects Elimination

    Institute of Scientific and Technical Information of China (English)

    张春明

    2012-01-01

    主要讲述了球铁飞轮的铁型覆砂铸造工艺的基本要求及生产过程控制,并对该生产工艺中可能出现的各种缺陷及其预防措施进行了总结.%The primary technological characteristics of permanent mold coated sand casting ductile iron fly wheel and its process control were described. Meanwhile, the defects possible encountered in production and countermeasures were presented.

  3. 大口径涂料法水冷金属型离心铸管机的设计%Design of Centrifugal Casting Machine for Pipe of Large Scale S.G.Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    习杰

    2011-01-01

    Design principle and method of centrifugal casting machine for production of pipe of large scale s.g. ductile cast iron with DN1000mm and above by coated water cooled die centrifugal casting have been mainly introduced.%主要介绍了DN1000以上大口径球墨铸铁管采用涂料法水冷金属型工艺生产时,离心铸管机的设计原理及方法.

  4. Corrosion behaviour of ductile cast irons partially modified with silicon in 0.03 M NaCl; Comportamiento frente a la corrosion de fundiciones con grafito laminar y esferoidal parcialmente modificadas con silicio en NaCl 0,03 M

    Energy Technology Data Exchange (ETDEWEB)

    Arenas, M. A.; Niklas, A.; Conde, A.; Mendez, S.; Sertucha, J.; Damborenea, J. J. de

    2014-07-01

    NaCl. The increasing demand of ductile cast irons with extensive technological applications leads to enlarge the corrosion resistance of this group of metallic materials. In this sense, the use of different chemical compositions on such cast irons becomes one of the most interesting aspects among the different ways to improve their behaviour against corrosion due to the extra opportunity for increasing the mechanical properties. Additionally such improvements have to be made without any increase of processing costs to keep the interesting competitiveness of developed cast irons. In the present work the preliminary results obtained from corrosion tests made on a group of cast irons with different chemical compositions are presented. Among ductile cast irons, silicon content has been varied in order to investigate the effect of this element on corrosion resistance of the alloys. The obtained results show a slight improvement of this property for the alloys with high silicon content with respect to the conventional ones though such effect was found in the first time period of the corrosion tests. Interestingly this improvement was found for alloys that exhibit better tensile properties than the conventional ductile irons. Thus an important way for developing new ductile cast irons with improved corrosion properties by alloying has been opened. (Author)

  5. The influence of the graphite mechanical properties on the constitutive response of a ferritic ductile cast iron – A micromechanical FE analysis

    DEFF Research Database (Denmark)

    Andriollo, Tito; Thorborg, Jesper; Hattel, Jesper Henri

    2015-01-01

    is considered and elasto-plastic behavior of both constituents is assumed; damage evolution in the ductile matrix is taken into account via Lemaitre’s isotropic model. Full 3D and 2D plane-stress finite element analyses are performed to simulate the loading conditions experienced by nodules located in the bulk...

  6. Influence of slit depth on impact value of ferritic nodular graphite cast iron. Feraito kyujo kokuen chutetsu no shogekichi ni oyobosu suritto fukasa no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sunada, H. (Himegi Inst. of Technology, Hyogo (Japan). Faculty of Engineering)

    1992-10-15

    Impact experiment and fracture surface observations were carried out in order to study the effect of slit depth on the impact value during austempering of ferrite spheroidal graphite east iron. The tensile strength has been increased by austempering, however the impact value was not improved. The bending strength of slit bottom for each structure has been less influenced by slit depth, and it has been almost similar, The value obtained by the multiplication by binding coefficient has been higher than yield strength in case of ferrite structure, and it has been lower in case of bainitic structure. Cleavage facets along with the large dimples originating from graphites and small dimples from inclursions, have been observed on the impact fracture surface of ferrite structure, however in general, the fracture has been ductile. The deformation around the graphite has been small for bainitic structure, pseudo brittleness type fracture surface is formed, and has been less rough compared to ferrite structure. 9 refs., 8 figs., 1 tab.

  7. 超低温高韧性球墨铸铁QT400-18AL的研究及应用%Research and Application of 400-18AL Ferrite Ductile Iron with High Toughness at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    马敬仲; 丁建中; 尤其光; 曾艺成

    2012-01-01

    The bogie bearing housing is one of the key parts for CRH300 high speed train, and is manufactured with QT400-18AL (-40 ℃) ferrite ductile iron. According to the demands of mechanical properties, high purity pig iron was used as metal charge. The foundry process, the chemical composition and microstructure are strictly controlled. The impact strength in different temperature are as follows: 20.8 J (20℃), 19.4 J (0℃), 19.2J (-20℃), 16.8 J (-40 ℃), 13.6 J (-50 ℃ ). The bogie bearing housing has been manufactured with this full ferrite ductile iron on batch production.%转向架轴箱为CRH300型高速列车核心部件,要求采用QT400-18AL (-40℃)球铁制造.在分析了生产这种球铁的技术难度及影响因素后,采用高纯生铁及综合技术措施研制成功全铁素体球铁转向架轴箱,其缺口冲击值分别为:20.8 J(20℃)、19.4J(0℃)、19.2 J(-20℃)、16.8 J(-40℃)、13.6J (-50℃),并首次给出这种铸铁的韧性、塑性转变曲线.

  8. Method of Estimating the Principal Characteristics of an Infantry Fighting Vehicle from Basic Performance Requirements

    Science.gov (United States)

    2013-08-01

    Balliett, “Investigation of Cast Austempered Ductile Iron (CADI) Trackshoes in T-158 Configuration,” US TACOM Report 13575 (Warren, MI: US Army Tank...Engineers, 11th Ed. New York, NY: McGraw Hill, 2007. Balliett, T. “Investigation of Cast Austempered Ductile Iron (CADI) Trackshoes in T-158

  9. Quality and Cost Assessment of Treatment with SiMg and NiCuMg Master Alloys vs Cored Wire in Production of Ductile Iron

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2007-07-01

    Full Text Available The results of studies on the use of magnesium alloy in modern cored wire injection method for production of nodular and vermicular graphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process high sulphur cupola iron held in ladles or iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery 47-70% for the production of vermicular and nodular graphite cast irons at Ścinawka Foundry, and for the production of nodular graphite iron at the following foundries: GZUT, KRAKODLEW, Centrozap - DEFKA, EE Zawiercie, WSK–Rzeszów, FWM PRZYSUCHA, HSW Stalowa Wola and PIOMA. The results of calculations and experiments have indicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The results of numerous trials have shown that the magnesium cored wire process can produce high quality nodular and vermicular graphite irons under the specific industrial conditions of the above mentioned foundries. It has also been proved that in the manufacture of nodular graphite iron, the cost of the nodulariser in the form of elastic cored wire is lower than the cost of the FeSiMg or NiCuMg master alloys.

  10. Effects of Austempering after Hot Deformation on the Mechanical Properties of Hot Rolled Si-Mn TRIP Steel Sheets

    Institute of Scientific and Technical Information of China (English)

    LI Zhuang; ZHANG Ping-li; WU Di

    2004-01-01

    Excellent mechanical properties are obtained by austempering after hot deformation without subsequent heat treatment in the present Si-Mn TRIP steel sheets. Isothermal holding time after finishing rolling has affected the mechanical properties of this steel. The results show that the sample exhibits a good combination of ultimate tensile strength and total elongation when it is held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase of isothermal holding time, and a further increase in the holding duration results in a decrease of it. The tensile strength, total elongation and strength ductility reach the maximum values(774MPa, 33% and 25542MPa% respectively) for this sort of hot rolled Si-Mn TRIP steel using the optimal technology.

  11. Development of a Cast Iron Fatigue Properties Database for use with Modern Design Methods

    Energy Technology Data Exchange (ETDEWEB)

    DeLa' O, James, D.; Gundlach, Richard, B.; Tartaglia, John, M.

    2003-09-18

    A reliable and comprehensive database of design properties for cast iron is key to full and efficient utilization of this versatile family of high production-volume engineering materials. A database of strain-life fatigue properties and supporting data for a wide range of structural cast irons representing industry standard quality was developed in this program. The database primarily covers ASTM/SAE standard structural grades of ADI, CGI, ductile iron and gray iron as well as an austempered gray iron. Twenty-two carefully chosen materials provided by commercial foundries were tested and fifteen additional datasets were contributed by private industry. The test materials are principally distinguished on the basis of grade designation; most grades were tested in a 25 mm section size and in a single material condition common for the particular grade. Selected grades were tested in multiple sections-sizes and/or material conditions to delineate the properties associated with a range of materials for the given grade. The cyclic properties are presented in terms of the conventional strain-life formalism (e.g., SAE J1099). Additionally, cyclic properties for gray iron and CGI are presented in terms of the Downing Model, which was specifically developed to treat the unique stress-strain response associated with gray iron (and to a lesser extent with CGI). The test materials were fully characterized in terms of alloy composition, microstructure and monotonic properties. The CDROM database presents the data in various levels of detail including property summaries for each material, detailed data analyses for each specimen and raw monotonic and cyclic stress-strain data. The CDROM database has been published by the American Foundry Society (AFS) as an AFS Research Publication entitled ''Development of a Cast Iron Fatigue Properties Database for Use in Modern Design Methods'' (ISDN 0-87433-267-2).

  12. Impact Properties of Copper-Alloyed and Nickel-Copper Alloyed ADI

    Science.gov (United States)

    Batra, Uma; Ray, Subrata; Prabhakar, S. R.

    2007-08-01

    The influence of austenitization and austempering parameters on the impact properties of copper-alloyed and nickel-copper-alloyed austempered ductile irons (ADIs) has been studied. The austenitization temperature of 850 and 900 °C have been used in the present study for which austempering time periods of 120 and 60 min were optimized in an earlier work. The austempering process was carried out for 60 min for three austempering temperatures of 270, 330, and 380 °C to study the effect of austempering temperature. The influence of the austempering time on impact properties has been studied for austempering temperature of 330 °C for time periods of 30-150 min. The variation in impact strength with the austenitization and austempering parameters has been correlated to the morphology, size and amount of austenite and bainitic ferrite in the austempered structure. The fracture surface of ADI failed under impact has been studied using SEM.

  13. Ductility of Nanostructured Bainite

    Directory of Open Access Journals (Sweden)

    Lucia Morales-Rivas

    2016-12-01

    Full Text Available Nanostructured bainite is a novel ultra-high-strength steel-concept under intensive current research, in which the optimization of its mechanical properties can only come from a clear understanding of the parameters that control its ductility. This work reviews first the nature of this composite-like material as a product of heat treatment conditions. Subsequently, the premises of ductility behavior are presented, taking as a reference related microstructures: conventional bainitic steels, and TRIP-aided steels. The ductility of nanostructured bainite is then discussed in terms of work-hardening and fracture mechanisms, leading to an analysis of the three-fold correlation between ductility, mechanically-induced martensitic transformation, and mechanical partitioning between the phases. Results suggest that a highly stable/hard retained austenite, with mechanical properties close to the matrix of bainitic ferrite, is advantageous in order to enhance ductility.

  14. Effects of slope plate variable and reheating on semi-solid structure of reheating on semi-solid structure of ductile cast iron

    OpenAIRE

    M. Nili-Ahmadabadi; Pahlevani, F.; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change ...

  15. Impact Behavior and Fracture Mechanism of Ductile Cast Iron with Minor Nickel Addition at Low Temperature%低镍球墨铸铁低温冲击性能及断裂机理研究

    Institute of Scientific and Technical Information of China (English)

    陈江; 黄兴民; 高杰维; 董海; 戴光泽

    2012-01-01

    使用激光共聚焦显微镜、扫描电镜和示波冲击等实验手段研究了镍元素(0.0%~0.9%,质量分数,下同)对球墨铸铁的微观组织和低温冲击性能的影响,对低温断裂机理进行了探讨.结果表明:含镍0.7%退火态球墨铸铁的韧脆转变温度低于-60℃,其-70℃下冲击功高于12J;适量镍元素添加能有效地细化晶粒和强化基体,改善球墨铸铁的低温冲击性能.%Utilizing laser confocal microscopy, SEM, instrumented impact and other experimental methods, the influence of nickel content(0. 0%-0. 9%,mass fraction, the same below) on the micro-structure and low temperature impact toughness of ductile cast iron(DCI) was investigated. The fracture mechanism of DCIs was studied further at different temperatures by using scanning electronic microscopy (SEM). The results show that ductile-to-brittle transition temperature of as-annealed DCIs with 0. 7% Ni content is lower than —60℃ , the impact energy of Charpy-type test is still higher than 12J at —70℃. Minor Ni addition of proper quantities might favor the grain refinement and matrix strengthen, low temperature impact toughness properties of DCIs are markedly improved.

  16. 对球墨铸铁中合理稀土用量的再认识%A Re-Understanding of the Proper RE Usage Amount in Ductile Iron Production

    Institute of Scientific and Technical Information of China (English)

    应忠堂

    2013-01-01

    The effect principle of rare earth in ductile iron was introduced.lt was confirmed by showing various productive examples of RE usage amount,that the proper RE usage amount range were as follows: (1)When producing medium and small parts of automobile, diesel engine, agricultural machine etc. by using cupola melting and tapping temperature is of 1 450 ~1 500 ℃ ,the S content of base iron is of 0.04%~0.06%,and Mg content of nodularizing alloy is of 6.5% for the lower limit to 7.5% for the upper limit,adding proper amount of rare earth is beneficial,however overabundance of RE will be inadvisable, the proper RE content range of nodularizing alloy is of 1.5% ~2.5% with its lower limit for thin section castings or casting having section thickness more than 50 mm. (2)When producing above mentioned castings by using medium frequency furnace melting and tapping temperature is of 1 500~1 550 ℃ ,the S content of base iron is about 0.02%,Mg content of nodularizing alloy is of 5.5%~6.5%,the proper RE content is about 0.8%.(3)When producing heavy section ductile iron castings by using cupola melting and Mg content of nodualrizing alloy is of 6.5%~7.5%,the proper RE content range is of 1.0%~1.2% and with heavy RE as its main RE ingredient.(4)When producing heavy ductile iron castings by using medium frequency furnace melting and Mg content of nodularizing alloy is of 5.5%~6.5%,the proper RE content range is of 0.6%~ 08% also with heavy RE as its main RE ingredient. It was stressed that the too high usage amount for ductile iron will not only increase productive cost, waste national precious resource,and also is disadvantageous to the casting quality.%介绍了稀土在球墨铸铁中的作用原理.通过各种稀土用量的生产实例,论证了合理的稀土用量范围:(1)对于冲天炉熔炼,出铁温度1 450~1 500℃,原铁液w(S) 0.04%~0.06%,生产汽车、柴油机、农机等中小型球墨铸铁件时,球化剂中w(Mg)在6.5%~7.5%,出铁温度高

  17. Iron

    Science.gov (United States)

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  18. Iron

    Science.gov (United States)

    ... of iron stored in the body become low, iron deficiency anemia sets in. Red blood cells become smaller and ... from the lungs throughout the body. Symptoms of iron deficiency anemia include tiredness and lack of energy, GI upset, ...

  19. 高硅钼涡轮壳支架的凝固模拟和铸造工艺研究%Research on Solidification Simulation and Casting Process for Turbine Housing Bracket of High-Si-Mo Ductile Iron

    Institute of Scientific and Technical Information of China (English)

    袁海; 王今胜; 高顺

    2012-01-01

    高硅钼涡轮壳支架结构类似于排气管.根据高硅钼球铁的技术要求,制定了合理的熔炼工艺参数,但在AMF造型线生产时,缩松导致的报废率很高.为了消除缩松缺陷实现大批量生产,提出了4种工艺改进方案,并用MAGMA软件对凝固过程进行模拟,最终确定的方案不但能解决缩松缺陷,还能简化工艺流程,提高生产效率.%The structure of turhine housing bracket was similar to an exhaust. According to the technical requirements of high silicon molybdenum ductile iron, the reasonable melting process parameters were drafted, but the shrinkage led to a low qualified rate when produced in AMF moulding line. In order to eliminate the shrinkage defects to achieve massive production, four kinds of process improvement program was presented, and their solidification processes were simulated by MAGMA software and the position of shrinkage was predicted. Finally the chosen scheme can eliminate the shrinkage defect, simplify process and improve production efficiency.

  20. 浅析消失模球铁管件生产中失圆变形的防治措施%Analysis on Preventing Ductile Iron in Lost Foam Casting from Deformation

    Institute of Scientific and Technical Information of China (English)

    王志刚

    2014-01-01

    采用消失模工艺生产薄壁壳体铸件最典型的就是球墨铸铁管件的生产,常因泡沫模样易变形而导致铸件尺寸超差和实圆变形;结合我们在生产中实践,介绍了防止泡沫模样变形和减轻铸件失圆变形的几项措施:如从模具组装、成型工艺和外加辅助手段方面进行控制,有效地减轻管件的变形缺陷。%It is typical to apply the lost foam casting to the production of ductile iron pipes. In the process, the possible deformation of foam pattern easily results in the dimension error and deformation of the castings. Based on the production practice, this paper discusses how to prevent the foam pattern and castings from deforming,and the effective measures are how to control the process of mold assembling and technology, and any possible assistant methods.

  1. OBSERVATION OF FATIGUE CRACK PATHS IN NODULAR CAST IRON AND ADI MICROSTRUCTURES

    Directory of Open Access Journals (Sweden)

    Lukáš Bubenko

    2009-07-01

    Full Text Available When speaking about quality of construction materials, fatigue crack propagation resistance is one of the most important considered properties. That is essentially influenced by character of matrix. Here presented contribution deals with the fatigue crack propagation mode through the matrix of as-cast nodular cast iron (NCI and austempered ductile iron (ADI, whereas influence of microstructure has been considered and discussed. Experimental materials used in presented contribution were pearlitc-ferritic NCI and heat treated ADI 800. Pearlitic-ferritic NCI was used as the base for ADI production. Experiments were performed on mini round compact tension (RCT specimens using an Amsler vibrophore. Fatigue crack paths in both materials were investigated and compared. Light microscopy was used to analyze the microstructure, crack initiation and propagation within broken specimens. In both tested materials fatigue cracks always initiated at graphite-matrix interface, while graphite nodules remained generally unbroken, eventually only surface of nodules was damaged. Though, comparing two materials with different microstructures, the diversity of fatigue crack propagation modes at high deltaK and low deltaK was observed.

  2. 我国铸铁生产技术回顾与展望%Review and Prospect of Production Technology of Cast Iron in China

    Institute of Scientific and Technical Information of China (English)

    李克锐; 曾艺成; 张忠仇; 吴现龙

    2012-01-01

    我国是铸铁生产大国,铸铁件产量约占世界的40%; 2010年我国铸铁件产量达到2 950万t(其中,灰铸铁1 900万t,球墨铸铁990万t),铸铁件占全部铸件产量的74.5%.本文回顾了60年来我国球墨铸铁、等温淬火球墨铸铁(ADI)、蠕墨铸铁和灰铸铁在生产技术、性能水平、技术标准、应用领域、质量检测和控制等方面的进展;对比分析了与国外先进工业国家在铸铁材质结构、生产规模、成分和性能波动、熔炼造型和质量控制等方面的差距;展望了铸铁生产技术发展趋势,供同行探讨和参考.%The annual output of iron castings in China has increased to 29.5 million tons in 2010 (including 19 million tons gray cast iron and 9.9 million tons ductile iron), which is about 40% of the world total. The production technology, mechanical properties, standard, application field, and quality control about ductile iron (DI), austempered ductile iron (ADI), compacted graphite cast iron (CGCI) and gray cast iron (GCI) castings in China were briefly reviewed and described. The gap in cast iron, production scale, component and properties consistency, process control etc. between China and industrial developed countries is compared and analyzed. The development trend of production technology of iron castings was forecasted, which provided the discussion and reference for the practitioners in the foundry field.

  3. Microstructure and Mechanical Properties of 50SiMnNiNb Steel by a Novel Quenching-Partitioning-Austempering Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    LI Hongyan; JIN Xuejun

    2009-01-01

    For the purpose of reducing weight of steel parts, save raw materials and keep or even improve safety standards, the development of advanced high strength steels is increasingly demanded in the automotive industry and engineering applications. We have proposed a novel heat treatment (quenching-partitioning-austempering treatment, Q-P-A) to obtain steel parts with high strength and good ductility. The Q-P-A process is intended to produce microstructure consisted of carbon-depleted martensite, carbon-enriched retained austenite and nanostructured bainite. Quenching(Q) treatment fabricates mixed microstructure of carbon-supersaturated martensite and certain amounts of untransformed austenite. Partitioning(P) thermal treatment accomplishes fully diffusing of carbon from the supersaturated martensite phase to the untransformed austenite phase and enriching the amount of carbon in untransformed austenite. Further low-temperature austempering(A) process induces incredible thin bainite from the carbon-enriched untransformed austenite. A study of the microstructure and mechanical properties of 50SiMnNiNb steel subjected to the novel Q-P-A treatment is presented. Microstructure is assessed by optical microscope(OM), field emission scanning electron microscope(FESEM) and transmission electron microscope(TEM), and the corresponding mechanical properties are measured. The experimental results indicate that attractive mechanical properties of steels during the Q-P-A process are attributed to the complex multi-phase structure. Slender plates of bainite with 20-40 nm thick are generated in the medium carbon steel. Meanwhile, with increasing of the volume fraction of nanostructured bainite, yield strength of steel parts is increased with little degradation of ultimate tensile strength. In this paper, a novel quenching-partitioning-austempering heat treatment is proposed, and the attractive mechanical properties of steels are obtained during the Q-P-A process.

  4. Study on the microstructure and mechanical properties of the cast QT750-5 synthetic ductile iron camshaft%铸态QT750-5合成球铁凸轮轴的组织及力学性能

    Institute of Scientific and Technical Information of China (English)

    陈忠士; 邹泽昌; 林燕清; 温丽娜

    2015-01-01

    采用先进的铁模覆砂铸造技术和废钢增碳技术,选择合适的化学成分和控制工艺来生产QT750-5合成球铁凸轮轴,其力学性能为:抗拉强度超过≥750 MPa,断后伸长率≥5%;基体组织是铁素体和珠光体的混合基体,基本无自由渗碳体和磷共晶存在,实现了内燃机凸轮轴材质从传统合金铸铁向高强高韧性球墨铸铁发展的飞跃。%The cast QT750-5 synthetic ductile iron camshaft was produced by using the advanced iron coated sand casting technology and scrap steel carburizing technology,with choosing the proper chemical composition and controlling production process. The tensile strength of the cast QT750-5 synthetic ductile iron camshaft was more than or equal to 750 MPa,and the elongation is greater than or equal to 5%. The matrix microstructure was the mixed matrix of ferrite and pearlite,and there was no free cementation and phosphorus eutectic. The development of the engine camshaft material from the traditional alloy cast iron to high strength and toughness ductile iron has been realized.

  5. Ductile transplutonium metal alloys

    Science.gov (United States)

    Conner, William V.

    1983-01-01

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

  6. Cast irons

    CERN Document Server

    1996-01-01

    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  7. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    The interest in the role of ferrous iron in diabetes pathophysiology has been revived by recent evidence of iron as an important determinant of pancreatic islet inflammation and as a biomarker of diabetes risk and mortality. The iron metabolism in the β-cell is complex. Excess free iron is toxic......, but at the same time, iron is required for normal β-cell function and thereby glucose homeostasis. In the pathogenesis of diabetes, iron generates reactive oxygen species (ROS) by participating in the Fenton chemistry, which can induce oxidative damage and apoptosis. The aim of this review is to present...... and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...

  8. Carbidic Bainitic and Ausferritic Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    Gumienny G.

    2013-12-01

    Full Text Available W arty kule przedstawiono nowe rodzaje żeliwa sferoidalnego z węglikami o różnej mikrostrukturze osnowy metalowej. Żeliwo to otrzymano stosując sferoidyzację metodą Inmold. zapewniającą dużą liczbę kulek grafitu i rozdrobnienie składników osnowy metalowej. Różną mikrostrukturę osnowy metalowej żeliwa otrzymywano bez stosowania obróbki cieplnej (w stanie surowym poprzez odpowiednią kombinację ilościową dodatków stopowych. Wykazano, że dodatek molibdenu, chromu, niklu i miedzi w żeliwie sferoidalnym pozwala uzyskać osnowę metalową złożoną z bainitu górnego, jego mieszaniny z dolnym lub ausferrytu w odlewach o grubości ściany 3^-25 mm. Proces krystalizacji żeliwa przedstawiono i opisano za pomocą krzywych analizy termicznej i derywacyjnej (ATD. Pokazano efekty cieplne od przemiany austenitu w stanie stałym

  9. Fading of inoculation effects in ductile iron

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2008-03-01

    Full Text Available In work i t has bccn shown rcsults or invcsligations of influcncc of rime Iapsed form inoculation proccss on graphitc nucleation potentialrcprcscntcd by: numbcr of graphitc nodulcs N and N,, maximum undercooling AT,, during solidification of gmphile eutcct ic. abmlutcchilling tcndcncy CT and critical casting diametct dh. undcr which cementite euteclic occur (so-callcd chills. Morcovcr it has hccncstima~cd raic of changc of N and N, AT,,,. CT and dk,. Also, it has bccn provcd that altcr onc minutc sincc rhc momcnt of inocuIationproccss nhout 35% of prnphttc nucIeation potenrial is tost. by 40% chitking tendency, by 70% incrcascs maximum undcrcmling forgraphitc ci~tccrica nd by nearly 40% caging diameter has to bc incrcascd in ordcr to avoid chills.

  10. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2009-01-01

    @@ This book consists of five sections:Chapter 1 Introduction,Chapter 2 Grey Iron,Chapter 3 Ductile Iron,Chapter 4Vermicular Cast Iron,and Chapter 5 White Cast Iron. CHINA FOUNDRY publishs this book in several parts serially,starting from the first issue of 2009.

  11. 46 CFR 56.60-10 - Cast iron and malleable iron.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Cast iron and malleable iron. 56.60-10 Section 56.60-10... APPURTENANCES Materials § 56.60-10 Cast iron and malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should...

  12. Ductile failure modeling

    DEFF Research Database (Denmark)

    Benzerga, Ahmed Amine; Leblond, Jean Baptiste; Needleman, Alan

    2016-01-01

    anisotropy, or the influence of nonlocal effects that bring a material size scale into the models. Often the voids are not present in the material from the beginning, and realistic nucleation models are important. The final failure process by coalescence of neighboring voids is an issue that has been given......Ductile fracture of structural metals occurs mainly by the nucleation, growth and coalescence of voids. Here an overview of continuum models for this type of failure is given. The most widely used current framework is described and its limitations discussed. Much work has focused on extending void...... growth models to account for non-spherical initial void shapes and for shape changes during growth. This includes cases of very low stress triaxiality, where the voids can close up to micro-cracks during the failure process. The void growth models have also been extended to consider the effect of plastic...

  13. Investigation of High Cycle Fatigue Life of MW Grade Wind Turbine Ductile Iron Hub%兆瓦级风电轮毂球铁高周疲劳寿命研究

    Institute of Scientific and Technical Information of China (English)

    刘佳; 曲迎东; 李荣德; 马广辉; 白彦华; 姜珂; 邱克强; 尤俊华; 王瑞春

    2012-01-01

    为了获得MW级风机轮毂QT350-22LT的高周疲劳寿命.通过拉-拉高周疲劳试验获得其疲劳极限,并通过数值模拟的方法确定QT350-22LT是否能够作为轮毂材料.疲劳试验在PW3-10程序控制高频万能疲劳试验机进行,采用实际生产的附铸试块进行拉-拉高周疲劳试验.试验结果表明:获得的兆瓦级风电轮毂QT350-22LT的疲劳极限值为250MPa,根据数据绘制的S-N曲线的拐点在290MPa;疲劳源的位置不同,所产生的瞬断区断口形貌也有所差别.对轮毂本身所能承受的最大应力进行有限元分析,得到最大应力为156MPa.应力集中部位的值没有超过材料的疲劳极限,这证明球铁QT350-22LT能够满足风机轮毂设计的应力要求.%The main purpose of this paper is to obtain high cycle fatigue life of MW grade the wheel hub (QT350-22 LT). Through the pull-pull high cycle fatigue tests, the fatigue limit is determined. The numerical simulation method was used to determine whether QT3 50-22 LT is able to be the hub material or not. The fatigue test equipment and materials are PW3-10 program control high frequency universal fatigue test machine and the practical production casting blocks, respectively. The results show that fatigue limit of the MW grade wind turbine hub QT350-22 LT is 250 MPa and inflection point of S-N curve draw according to data is 290 MPa; the morphologies of the transient breaking fracture are different due to the different crack sources. The maximum tensile stress of the hub is 156 MPa, which is obtained by the finite element analysis. The value of tensile stress concentration position is no more than the fatigue limit of the material, which proves that the ductile iron hub (QT350-22 LT) can satisfy the design requirement of stress.

  14. Development competence of an iron/steel foundry in the field of tension between material selection and production technology for engine components; Entwicklungskompetenz einer Eisen-/Stahlgiesserei im Spannungsfeld von Werkstoffauswahl und Fertigungstechnologie fuer Motorenbauteile

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R. [Eisenwerk Bruehl GmbH, Bruehl (Germany)

    2007-07-01

    If we had to summarize all aspects of the combustion engine subject, engine development is - from the viewpoint of an iron and steel foundry specialist - mainly controlled by environmental protection (CO{sub 2}) and saving energy (raw material shortage). We will always consider today's development targets, which are based on fuel reduction and power increase. To focus on development today means to focus on emission sources, on exhaust treatment and on a medium term change to alternative driving systems. Implementing these targets will always be in the focus and solutions will have to be found in the automotive industry on a continuous basis. Some of the initial phases are directly linked to the foundry and their production technology and casting material. Being foundry specialists we have to adjust our efforts for new strategies to these requirements. ERW group together with Eisenwerk Bruehl GmbH and Eisenwerk Hasenclever are going to show their methodology with the help of three examples for developing material- / production technology in CGI with vermicular-type graphite, ADI - austempered ductile iron and cast steel. (orig.)

  15. OPTIMIZATION OF CHEMICAL COMPOSITION AND HEAT TREATMENT TO AUSTEMPERED DUCTILE IRON BASED ON ARTIFICIALNEURAL NETWORKS%基于人工神经网络的奥贝球铁化学成分及热处理工艺优化设计

    Institute of Scientific and Technical Information of China (English)

    周小平

    2003-01-01

    以奥贝球铁的力学性能指标为输入,化学成分及热处理工艺为输出,建立了7×5×7结构的BP神经网络,经过训练学习,网络输出具有较高的精度,适用于奥贝球铁化学成分及热处理工艺的优化设计.

  16. 硅锰对室温油分级等温淬火贝氏体球墨铸铁组织和性能的影响%Effects of Si and Mn on Microstructure and Mechanical Properties of Bainite Ductile Iron by Step Austempering in Room-Temperature Machine Oil

    Institute of Scientific and Technical Information of China (English)

    魏德强; 恽志东; 刘军

    2008-01-01

    研究了室温油分级等温淬火时,硅和锰对贝氏体球墨铸铁磨球组织和性能的影响.试验结果表明:硅含量在3.3%~3.8%时,对贝氏体相变具有诱发作用,使贝氏体球铁组织细化,力学性能提高,锰使贝氏体球墨铸铁的硬度提高韧性降低,合理的硅锰量可提高贝氏体球墨铸铁的力学性能.

  17. Thin Wall Iron Castings

    Energy Technology Data Exchange (ETDEWEB)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  18. Effects of Austempered Temperature On Microstructure and Properties of Tungstenic CADI%盐浴温度对含钨CADI材料组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    朱耀; 李继林; 李永杰; 赵明纯

    2016-01-01

    将含钨的碳化物的等温淬火球墨铸铁(Carbidic Austempered Ductile Iron简称CADI)铸件在900℃高温奥氏体化后,在盐浴不同温度等温处理及保温不同的时间,对试样作力学性能和耐磨性对比测试.结果表明,当盐浴温度为280℃时硬度最高,耐磨性最好.但冲击韧度较小;当温度提高到340℃,C曲线左移,贝氏体晶粒粗化,试样的硬度下降此时材料的冲击韧度最好.

  19. Influence of Hot Deformation and Subsequent Austempering on the Mechanical Properties of Hot Rolled Multiphase Steel

    Institute of Scientific and Technical Information of China (English)

    Zhuang LI; Di WU

    2006-01-01

    Influence of hot deformation and subsequent austempering on the mechanical properties of hot rolled multiphase steel was investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, where three different kinds of finishing rolling reduction, and austemperings with various isothermal holding duration were applied. The results have shown that a multiphase microstructure consisting of polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes. Mechanical properties increase with increasing the amount of deformation because of the stabilization of retained austenite. Ultimate tensile strength (σb), total elongation (δ)36% and 28476 MPa%, respectively) at optimal processes.

  20. Structural durability criteria for commercial vehicle components from the self strengthening cast ausferrite nodular iron EN-GJS-800-8 (ADI) in comparison to the ferritic EN-GJS-400-15

    Energy Technology Data Exchange (ETDEWEB)

    Zinke, R.; Heinrietz, A.; Heim, R.; Hanselka, H. [Fraunhofer Institut fuer Betriebsfestigkeit LBF, Darmstadt (Germany); Streicher, M. [MAN Nutzfahrzeuge AG, Munich (Germany); Sonsino, C.M.

    2008-10-15

    The structural durability of safety components in the chassis comprises not only the fatigue behaviour under cyclic variable amplitude service loading, but also its interaction with prestrains caused by special events and the rupture behaviour under impact loading due to misuse. From this background, the structural durability behaviour of Panhard rods made from ferritic cast nodular iron EN-GJS-400-15 was compared with the behaviour of rods made from the austempered EN-GJS-800-8. The components investigated, Panhard rods and cast plugs, made from the austempered material revealed a higher impact resistance than the components made from the ferritic cast nodular iron. Due to their ausferrite microstructure, Panhard rods made from EN-GJS-800-8 display a significantly superior fatigue strength behaviour, especially under spectrum loading, and offer a potential for lightweight design. Prestrains do not affect the fatigue behaviour under variable amplitude loading and the plastic deformation of the component under impact loading can be increased by appropriate design reducing the stiffness in the shaft area and achieving a weight reduction by 15 %. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Die Betriebsfestigkeit von Fahrwerksbauteilen wird nicht nur von der Schwingfestigkeit unter zyklischen Betriebsbelastungen und Missbrauchsbelastungen bestimmt, sondern auch durch die Interaktion mit Sonderbelastungen und Missbrauchsbelastungen. Vor diesem Hintergrund wird anhand eines Panhard-Stabes, ein stabilisierendes Element im Fahrwerk von Nutzfahrzeugen, gezeigt, wie zunaechst durch eine Werkstoffsubstitution, naemlich des konventionellen Eisengraphitgusses EN-GJS-400-15 (GGG 40), durch die ADI (Ausferrite Ductile Iron)-Variante EN-GJS-800-8 mit der entsprechenden Waermebehandlung eine deutlich hoehere Schwingfestigkeit erzielt wird. Zu bemerken ist, dass der ADI-Guss gefuegebedingt gegenueber dem konventionellen ferritischen Werkstoff unter variablen