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Sample records for wall ductile cast

  1. 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...

  2. 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.

  3. 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....

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Solidification of Hypereutectic Thin Wall Ductile Cast Iron

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2006-01-01

    Hypereutectic ductile iron was cast in green sand moulds with four plates with thickness of 1.5, 2, 3 and 4 mm in each mould. Temperatures were measured in the 3 and 4 mm plate. The temperature curves showed that eutectic solidification was divided into two stages: primary and secondary eutectic...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

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

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels

    2005-01-01

    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...

  15. Undercooling and nodule count in thin walled ductile iron castings

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2007-01-01

    Casting experiments have been performed with eutectic and hypereutectic castings with plate thick¬nesses from 2 to 8 mm involving both temperature measurements during solidification and micro¬structural examination afterwards. The nodule count was the same for the eutectic and hypereutectic...... castings in the thin plates ( 4.3 mm) while in the 8 mm plate the nodule count was higher in the hypereutectic than in the eutectic castings. The minimum temperature prior to the eutectic recalescence (Tmin) was 15 to 20C lower for the eutectic than the hypereutectic castings. This is due to nucleation...... of graphite nodules which begins at a lover temperature in the eutectic than in the hypereutectic castings The recalescence (Trec) was however also larger for the eutectic casting and in the thin plates the maximum temperature after recalescence (Tmax) was the same in the eutectic and hypereutectic plates...

  16. Undercooling and nodule count in thin walled ductile iron castings

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2007-01-01

    Casting experiments have been performed with eutectic and hypereutectic castings with plate thicknesses from 2 to 8 mm involving both temperature measurements during solidification and microstructural examination afterwards. The nodule count was the same for the eutectic and hypereutectic castings...... in the thin plates (≤4.3 mm) while in the 8 mm plate the nodule count was higher in the hypereutectic than in the eutectic castings. The minimum temperature before the eutectic recalescence (Tmin) was 15 to 20ºC lower for the eutectic than for the hypereutectic castings. This is due to nucleation of graphite...... nodules which begins at a lower temperature in the eutectic than in the hypereutectic castings. The recalescence ∆Trec was however also larger for the eutectic casting and in the thin plates the maximum temperature after recalescence (Tmax) was the same in the eutectic and hypereutectic plates...

  17. 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....

  18. 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...

  19. 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.

  20. 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...

  1. 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....

  2. 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.

  3. Thin Wall Austempered Ductile Iron (TWADI

    Directory of Open Access Journals (Sweden)

    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.

  4. Temperature measurement during solidification of thin wall ductile cast iron. Part 2: Numerical simulations

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2008-01-01

    Temperature measurements in castings are carried out with thermocouples (TC’s), which are inserted in the melt. The TC influence solidification of the casting, especially in thin wall castings where the heat content of the melt is small compared to the cooling power of the TC. A numerical analysis...... of factors influencing temperature measurement in thin walled castings was carried out. The calculations are based on and compared with experiments presented in part 1 of this paper. The analysis shows that the presence of the TC has only a minor influence on the microstructure of the casting. The influence...

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. Machinable, Thin-Walled, Gray and Ductile Iron Casting Production, Phase III

    Energy Technology Data Exchange (ETDEWEB)

    Charles Bates; Hanjun Li; Robin Griffin

    2003-12-08

    This report presents the results of research conducted to determine the effects of normal and abnormal processing and compositional variations on machinability (tool wear rate) of gray and ductile iron. The procedures developed allow precise tool wear measurements to be made and interpreted in terms of microstructures and compositions. Accurate data allows the most efficient ways for improving machinability to be determined without sacrificing properties of the irons.

  10. 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.

  11. 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.

  12. 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.

  13. Engineered Cooling Process for High Strength Ductile Iron Castings

    Science.gov (United States)

    Lekakh, Simon N.; Mikhailov, Anthony; Kramer, Joseph

    Professor Stefanescu contributed fundamentally to the science of solidification and microstructural evolutions in ductile irons. In this article, the possibility of development of high strength ductile iron by applying an engineered cooling process after casting early shake out from the sand mold was explored. The structures in industrial ductile iron were experimentally simulated using a computer controlled heating/cooling device. CFD modeling was used for process simulation and an experimental bench scale system was developed. The process concept was experimentally verified by producing cast plates with 25 mm wall thickness. The tensile strength was increased from 550 MPa to 1000 MPa in as-cast condition without the need for alloying and heat treatment. The possible practical applications were discussed.

  14. 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...

  15. 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.

  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. 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.

  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. 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.)

  20. 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.

  1. 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...

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. SCALE/MAVRIC calculation of dose rates measured for a gamma radiation source in a thick-walled transport and storage cask of ductile cast iron with lead inserts

    Science.gov (United States)

    Baumgarten, Werner; Thiele, Holger; Ruprecht, Benjamin; Phlippen, Peter-W.; Schlömer, Luc

    2017-09-01

    Dose rate calculations are important for judging the shielding performance of transport casks for radioactive material. Therefore it is important to have reliable calculation tools. We report on measured and calculated dose rates near a thick-walled transport and storage cask of ductile cast iron with lead inserts and a Co-60 source inside. In a series of experiments the thickness of the inserts was varied, and measured dose rates near the cask were compared with SCALE/MAVRIC 6.1.3 and SCALE/MAVRIC 6.2 calculation results. Deviations from the measurements were found to be higher for increased lead thicknesses. Furthermore, it is shown how the shielding material density, air scattering and accounting for the floor influence the quality of the calculation.

  8. 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...

  9. 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.

  10. Hot ductility of continuously cast structural steels

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, S.M. [Materials Science and Technology Institute, Cracow University of Technology, Cracow (Poland)

    1995-12-31

    The objective of this investigation was to explain the hot ductility of the structural steels characterized by different amount of carbon and morphology of sulfides. Two different rolling processes were simulated under computer controlled, high temperature deformation MTS system. Results of this study show that morphology of sulfides as well as temperature and amount of deformation are responsible for level of hot ductility of the steel tested. (author). 7 refs, 5 refs, 4 tabs.

  11. 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...

  12. 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%.

  13. 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...

  14. 3D Quantitative Analysis of Graphite Morphology in Ductile Cast Iron by X-ray Microtomography

    Science.gov (United States)

    Yin, Yajun; Tu, Zhixin; Zhou, Jianxin; Zhang, Dongqiao; Wang, Min; Guo, Zhao; Liu, Changchang; Chen, Xiang

    2017-08-01

    In this article, X-ray microtomography and color metallographic techniques have been used to perform three-dimensional quantitative characterization of graphite nodule morphology in a step-shaped ductile cast iron casting. Statistical analyses of the graphite nodule count, diameter, sphericity, and spatial distribution have been processed for three samples in detail. The results reveal that graphite nodules in ductile cast iron can be categorized into two categories. The first types are nodules located in eutectic cells (NIECs), and the other one refers to nodules located between the eutectic cells (NBECs). The NIECs possess a larger average diameter but smaller sphericity compared with the NBECs, and the sphericity decreases along with the increasing of diameter. The increasing casting thickness results in an increasing count and percentage of NBECs. In addition, most nodules are NIECs in thin walls instead of NBECs in thick walls. Nonuniform spatial distributions of graphite nodules caused by the existence of NBECs have been found to become more obvious along with the increase of cast thickness.

  15. 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.

  16. 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.

  17. 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.

  18. 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 resul...

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. Nondestructive Evaluation of the Austempered Ductile Cast Irons

    Energy Technology Data Exchange (ETDEWEB)

    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

  4. Fillability of Thin-Wall Steel Castings

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. Hot ductility behavior of Incoloy 901 superalloy in the cast and wrought conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shore, Fatemeh Mohammadi; Morakabati, Maryam; Mahdavi, Rashid [AMR of Technology, Tehran (Iran, Islamic Republic of). Metallic Material Dept.

    2014-04-15

    Hot ductility was investigated in Incoloy 901 using hot tensile testing over a temperature range of 900 to 1200 C and at strain rates of 0.01 to 1 s{sup -1}, in the cast and wrought conditions. Maximum ductility was detected in the cast and wrought conditions at temperature ranges of 1000 to 1050 C and 1000 to 1100 C, respectively. More voids were seen at the fracture surface of the wrought specimens compared to the cast ones. At 950 C, the formation of large and non-homogeneous voids at the fracture surface, as well as the appearance of transgranular and intergranular cracks in the wrought specimen, support moderate ductility of the alloy. Microstructural analysis does not support the occurrence of dynamic recrystallization in the cast specimens. In contrast, dynamic recrystallization in the wrought specimens at the region of maximum hot ductility promoted diffusion, leading to ductile fracture. At temperatures higher than the maximum ductility range, the formation of intergranular cracks resulted in a remarkable decline in ductility. (orig.)

  13. 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...

  14. Displacement ductility for seismic design of RC walls for low-rise housing

    OpenAIRE

    Carrillo,Julian; González, Giovanni; Rubiano, Astrid

    2014-01-01

    The paper compares and discusses displacement ductility ratios of reinforced concrete walls typically used in one- and two-story houses. Ductility is investigated by assessing response measured on 39 walls tested under shaking table excitations and quasi-static lateral loads. Variables studied were the height-to-length ratio and walls with openings, type of concrete and, steel ratio and type of web reinforcement. An equation to estimate the available ductility of a wall is proposed. Based on ...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Influence of copper on effects of precipitation hardening of ductile cast iron

    Directory of Open Access Journals (Sweden)

    T. Szykowny

    2008-10-01

    Full Text Available Ductile cast iron with different copper content was precipitation hardened. Cast iron with 0.48 % Cu content was ferritized. That operation was ended with rapid quenching, and then aged. Cast iron with 1.27 or 2.10 % Cu content was spheroid annealing. After rapid quenching cast iron was aged. Not alloy cast iron with small copper content (0.04 % had a chemical composition similar to cast iron with 0.48 % Cu content. Such copper was for tests in order to obtain an answer for the question whether only copper is responsible for precipitate hardening effects. Metalographic microscope tests (LM, SEM of mechanical properties (Rm, Rp, A5, Z, K and H and x-ray diffraction tests were performed. It has been stated, that hardening of ferretic cast iron let to obtain tensile strength above 500 MPa and elongation approx. 23 %.Precipitation hardening of ductile cast iron efficiently compensates reducing of hardening caused by partial graphitization and spheroidization of pearlitic cementite.

  20. 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».

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. INVESTIGATION ON HOT DUCTILITY AND STRENGTH OF CONTINUOUS CASTING SLAB FOR AH32 STEEL

    Institute of Scientific and Technical Information of China (English)

    G.Y. Li; X.F. Li; L.G. Ao

    2006-01-01

    By means of Gleeble-1500 testing machine, the simulation of continuous casting process for AH32 steel was carried out and hot ductility and strength were determined. The cracking sensitivity was studied under the different temperatures and strain rates. The Precipitations of AlN at different temperatures and the fractures of high-temperature tensile samples were observed by using TEM (transmission electron microscope) and SEM (scanning electron microscope). The factors affecting the brittle temperature zone were discussed.

  10. Rolling Contact Fatigue Failure Mechanisms of Plasma-Nitrided Ductile Cast Iron

    Science.gov (United States)

    Wollmann, D.; Soares, G. P. P. P.; Grabarski, M. I.; Weigert, N. B.; Escobar, J. A.; Pintaude, G.; Neves, J. C. K.

    2017-05-01

    Rolling contact fatigue (RCF) of a nitrided ductile cast iron was investigated. Flat washers machined from a pearlitic ductile cast iron bar were quenched and tempered to maximum hardness, ground, polished and divided into four groups: (1) specimens tested as quenched and tempered; (2) specimens plasma-nitrided for 8 h at 400 °C; (3) specimens plasma-nitrided and submitted to a diffusion process for 16 h at 400 °C; and (4) specimens submitted to a second tempering for 24 h at 400 °C. Hardness profiles, phase analyses and residual stress measurements by x-ray diffraction, surface roughness and scanning electron microscopy were applied to characterize the surfaces at each step of this work. Ball-on-flat washer tests were conducted with a maximum contact pressure of 3.6 GPa, under flood lubrication with a SAE 90 API GL-5 oil at 50 °C. Test ending criterion was the occurrence of a spalling. Weibull analysis was used to characterize RCF's lifetime data. Plasma-nitrided specimens exhibited a shorter RCF lifetime than those just quenched and tempered. The effects of nitriding on the mechanical properties and microstructure of the ductile cast iron are discussed in order to explain the shorter endurance of nitrided samples.

  11. 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...

  12. Effect of Cu and Mn on the Mechanical Properties and Microstructure of Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    A.M.Omran

    2014-06-01

    Full Text Available This paper described the method used for producing ductile cast iron (SGI. The processing parameters affecting the production of SGI were studied. These parameters include chemical composition, castings thickness, mechanical properties, alloying elements and microstructure. The chemical composition of producing SGI was optimized. The nodularity was increased with increasing the percentages of Mg content and with decreasing the castings thickness. The amount of pearlite and mechanical properties were increased sharply with increasing Cu and Mn contents in the produced SGI. Empirical equations were correlated to indicate the relations among nodularity, Mg content and other parameters. The results shown also as the post inoculation increased the metallurgical quality was improved. The suitability of SGI as automotive engine was tested and different empirical correlations were obtained

  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. 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. 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...... but with a significant overprediction of the maximum strain. This is discussed in terms of stress relaxation during cooling or during storage by plastic deformation of the nodule, the matrix or both. Relaxation by plastic deformation of the ferrite is demonstrated by the formation of low energy dislocation cell...... structure also quantified by the DAXM technique....

  16. 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.

  17. Influence of mean stress on fatigue strength of ferritic-pearlite ductile cast iron with small defects

    Science.gov (United States)

    Deguchi, T.; Kim, H. J.; Ikeda, T.; Yanase, K.

    2017-05-01

    Because of their excellent mechanical properties, low cost and good workability, the application of ductile cast iron has been increased in various industries such as the automotive, construction and rail industries. For safety designing of the ductile cast iron component, it is necessary to understand the effect of stress ratio, R, on fatigue limit of ductile cast iron in the presence of small defects. Correspondingly in this study, rotating bending fatigue tests at R = -1 and tension-compression fatigue tests at R = -1 and 0.1 were performed by using a ferritic-pearlitic ductile cast iron. To study the effects of small defects, we introduced a small drilled hole at surface of a specimen. The diameter and depth of a drilled hole were 50, 200 and 500 μm, respectively. The non-propagating cracks emanating from graphite particles and holes edge were observed at fatigue limit, irrespective of the value of stress ratio. From the microscopic observation of crack propagation behavior, it can be concluded that the fatigue limit is determined by the threshold condition for propagation of a small crack. It was found that the effect of stress ratio on the fatigue limit of ductile cast iron with small defects can be successfully predicted based on \\sqrt {area} parameter model. Furthermore, a use of the tensile strength, σ B, instead of the Vickers hardness, HV, is effective for fatigue limit prediction.

  18. 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.

  19. 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.

  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. 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.

  2. 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.

  3. Newly developed vacuum differential pressure casting of thin-walled complicated Al-alloy castings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The newly designed vacuum differential pressure casting (VDPC) unit was introduced, by which the capability of the VDPC process to produce thin-walled complicated Al-alloy castings, that are free from oxides, gas pore and shrinkage cavity and thus enhance overall part quality, was studied. Experimental results were compared with those of traditional gravity pouring and vacuum suction casting. The first series of experiments were focused on investigating the castability of thin section Al-alloy casting. In the second series of experiments the metallographic evidence, casting strength and soundness were examined. Finally, case studies of very interesting thin walled complicated casting applications were described. The advantages of the described technique have made possible to produce thin walled complicated Al-alloy casting (up to a section thickness of 1 mm), which is not practical for gravity pouring and vacuum suction casting.

  4. 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

  5. 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.)

  6. Manufacturing of thin walled near net shape iron castings

    DEFF Research Database (Denmark)

    Larsen, Per Leif

    2003-01-01

    The demand for near net shape thin walled iron castings is growing. This has several reasons, the main one is the need for lowering the fuel consumption of cars; the easiest way to do that is to lower the weight of the cars. The best way to do this was for a period of time believed...... to be substituting iron casings with aluminum castings. Substituting iron castings with aluminum castings is not as easy as first believed, and hence the substitution is very slow. This combined with the lack of fully exploiting the potential in iron castings, makes research in iron castings interesting. The 60.......000.000 cars produced world wide each year consumes enormous amounts of cast parts ! The aim of the project is to develop the green sand molding method on DISAMATIC to be able to deal with the new demands for thin walled near net shape castings in iron....

  7. Ductile iron castings fabricated using metallic moulds; Fabricacion de piezas de fundicion con grafito esferoidal en molde metalico

    Energy Technology Data Exchange (ETDEWEB)

    Urrestarazu, A.; Sertucha, J.; Suarez, R.; Alvarez-Ilzarbe, I.

    2013-07-01

    The features and suitability of high requirements ductile iron castings production using metallic moulds have been studied in the present work. The structural and mechanical properties of the produced castings have been analysed and compared to the corresponding ones but fabricated using green sand moulds according to a conventional production process. The higher cooling rate in the metallic moulds is the main cause for the appearance of the detected structural changes in castings. The mechanical and microstructural properties obtained directly on castings are remarkable due to the higher nodule count among other factors. Finally, the benefits and inconveniences found in this kind of production methodology using metallic moulds are also discussed. (Author)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Synchrotron measurements of local microstructure and residual strains in ductile cast iron

    Science.gov (United States)

    Zhang, Y. B.; Andriollo, T.; Fæster, S.; Liu, W.; Sturlason, A.; Barabash, R.

    2017-07-01

    The local microstructure and distribution of thermally induced residual strains in ferrite matrix grains around an individual spherical graphite nodule in ductile cast iron (DCI) were measured using a synchrotron X-ray micro-diffraction technique. It is found that the matrix grains are deformed, containing dislocations and dislocation boundaries. Each of the residual strain components in the matrix grains exhibits a complex pattern along the circumferential direction of the nodule. Along the radial direction of the nodule, strain gradients from the interface to the grain interior are seen for some strain components, but only in some matrix grains. The observed residual strain patterns have been analysed by finite element modelling, and a comparison between the simulation and experiments is given. The present study of local residual stress by both experimental characterization and simulation provide much needed information for understanding the mechanical properties of DCI, and represent an important contribution for the microstructural design of new DCI materials.

  17. 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.

  18. 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.

  19. The influence of self-compacting steel fibre reinforced concrete infill on the flexure strength and ductility of masonry walls

    OpenAIRE

    Oliveira, Luiz António Pereira de; Bernardo, Luís Filipe Almeida

    2010-01-01

    This paper presents an experimental study on the influence of longitudinal reinforcement ratio and steel fibre volume in self-compacting concrete infill on the strength and ductility of reinforced masonry walls subjected to flexure. Flexure tests were performed as four-point bending tests on twelve walls. The analysis of the concrete infill contribution to the walls capacity is made considering recent recommendations for steel fibre reinforced concrete design. A ductility...

  20. 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.

  1. 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.

  2. 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.

  3. Effects of Alloying Elements (Mo, Ni, and Cu on the Austemperability of GGG-60 Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    Erkan Konca

    2017-08-01

    Full Text Available The interest in austempered ductile irons (ADI is continuously increasing due to their various advantageous properties over conventional ductile irons and some steels. This study aimed to determine the roles of alloying elements Ni, Cu, and Mo, on the austemperability of GGG-60 ductile cast iron. Two different sets of GGG-60 (EN-GJS-600-3 samples, one set alloyed with Ni and Cu and the other set alloyed with Mo, Ni, and Cu, were subjected to austempering treatments at 290 °C, 320 °C, and 350 °C. A custom design heat treatment setup, consisting of two units with the top unit (furnace serving for austenitizing and the 200 L capacity bottom unit (stirred NaNO2-KNO3 salt bath serving for isothermal treatment, was used for the experiments. It was found that austempering treatment at 290 °C increased the hardness of the Ni-Cu alloyed GGG-60 sample by about 44% without causing a loss in its ductility. In the case of the Mo-Ni-Cu alloyed sample, the increase in hardness due to austempering reached to almost 80% at the same temperature while some ductility was lost. Here, the microstructural investigation and mechanical testing results of the austempered samples are presented and the role of alloying elements (Mo, Ni, and Cu on the austemperability of GGG-60 is discussed.

  4. 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.

  5. The effect of grain refinement on the room-temperature ductility of as-cast Fe{sub 3}Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, S.; Andleigh, V.K.; McKamey, C.G. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Fe{sub 3}Al-based alloys exhibit poor room-temperature ductility in the as-cast condition. In this study, the effect of grain refinement of the as-cast alloy on room-temperature ductility was investigated. Small melts of Fe-28 at. % Al-5 at. % Cr were inoculated with various alloying additions and cast into a 50- x 30- x 30-mm graphite mold. The resulting ingots were examined metallographically for evidence of grain refinement, and three-point bend tests were conducted on samples to assess the effect on room-temperature ductility. Ductility was assumed to correlate with the strain corresponding to the maximum stress obtained in the bend test. The results showed that titanium was extremely effective in grain refinement, although it severely embrittled the alloy in contents exceeding 1%. Boron additions strengthened the alloy significantly, while carbon additions reduced both the strength and ductility. The best ductility was found in an alloy containing titanium, boron, and carbon. In order to verify the results of the grain refinement study, vacuum-induction melts of selected compositions were prepared and cast into a larger 25- x 150- x 100-mm graphite mold. Tensile specimens were machined from the ingots, and specimens were tested at room temperature. The results of the tensile tests agreed with the results of the grain refinement study; in addition, the addition of molybdenum was found to significantly increase room-temperature tensile ductility over that of the base alloy.

  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. 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.

  8. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

    Science.gov (United States)

    Dang, B.; Zhang, X.; Chen, Y. Z.; Chen, C. X.; Wang, H. T.; Liu, F.

    2016-08-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

  9. Comparison of residual stresses in sand- and chill casting of ductile cast iron wind turbine main shafts

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Frandsen, J. O.; Hattel, Jesper Henri

    2015-01-01

    In this work, simulations of pouring, solidification and cooling, and residual stress evolution of sand and chill cast wind turbine main shafts is performed. The models are made in the commercial software MAGMAsoft. As expected, the cooling rate of the sand casting is shown to be much lower than...... for the chill casting, resulting in a very course microstructure.From the simulations the nodule count is found to be 17 nodules per mm2 and 159 nodules permm2 for the sand and chill casting, respectively, in the critical region of the main bearing seat.This is verified from nodule counts performed on the real...... cast main shafts. Residual stressevaluations show an overall increase of the maximum principal stress field for the chill casting,which is expected. However, the stresses are found to be in compression on the surface of thechill cast main shaft, which is unforeseen....

  10. 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.

  11. 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...

  12. 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.

  13. Test and Analysis of a New Ductile Shear Connection Design for RC Shear Walls

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

    2016-01-01

    This paper presents a new and construction-friendly shear connection for assembly of precast reinforced concrete shear wall elements. In the proposed design, the precast elements have indented interfaces and are connected by a narrow zone grouted with mortar and reinforced with overlapping U......-bar loops. Contrary to the classical shear connections, the planes of the U-bar loops are here parallel to the plane of the wall elements. This feature enables a construction-friendly installation of the elements without the risk of rebars clashing. The core of mortar inside each U-bar loop is reinforced...... with a transverse double T-headed bar to ensure transfer of tension between the overlapping U-bars. Push-off tests show that a significantly ductile load-displacement response can be obtained by the new solution as compared to the performance of the conventional keyed shear connection design. The influence...

  14. 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.

  15. 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.

  16. 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...

  17. Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

    Directory of Open Access Journals (Sweden)

    C. Labrecque

    2011-02-01

    Full Text Available A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT, 16 J (-20°C and 11 J (-40°C. The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation.

  18. 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.

  19. 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.

  20. Effect of Mould Wall Thickness on Rate of Solidification of Centrifugal Casting

    Directory of Open Access Journals (Sweden)

    Madhusudhan

    2010-11-01

    Full Text Available In Centrifugal Casting process the centrifugal force presses the metal against the inner wall of the metal mould, resulting in rapid solidification of the molten metal. However the solidification structures like structural uniformity and structural character of the solidified metal of centrifugal casting is of great importance, regarding to its mechanical properties. The solidification time of the casting is dependent upon the various parameters like speed ofrotation of the mold, mould wall temperature, heat transfer coefficient at the metal-mold interface, mould wall thickness, material of the mould and so on. In this paper experimental study of effect of mould wall thickness on solidification of the centrifugal casting has been discussed. As the mould wall thickness increases, due to the chilling effect, the solidification time decreases. Fine grains are observed in castings produced in thick walled mould and coarse grains are observed in thin walled moulds. Brinel Hardness of the casting was measured.

  1. Effect of microstructure on mechanical properties of a thin-walled cast duplex steel

    Energy Technology Data Exchange (ETDEWEB)

    Petzold, L.; Kreschel, T.; Peisker, D. [TU Bergakademie Freiberg, Institut fuer Eisen- und Stahltechnologie, Freiberg (Germany); Minnich, D. [Evosteel GmbH, Leipzig (Germany)

    2010-06-15

    The paper investigates the microstructure and the resulting mechanical properties of a duplex steel cast in sand dead-moulds. The chemical composition and the cooling rate are the main parameters affecting the properties. The chemical composition influences the thermodynamics of the phase transformation, the cooling rate determines the kinetics of formation of the microstructure. The latter varies with changes in wall thickness (investigated from 2 to 7 mm) and the position of the material within the casting. Through heat treatment, the composition of the microstructural components can be changed selectively afterwards, thereby the properties are improved. The correlation between microstructure and mechanical properties is explained quantitatively. Additionally to the austenite-ferrite ratio, the dispersion of microstructure has a large influence on the mechanical properties. Ranges of chemical composition and heat treatment parameters are identified where third phases, such as carbides and {sigma}-phase tend to occur. These influence the properties very sensitively even in small amounts. Finally, structural parameters are recognized that will lead to optimal combinations of properties. With an appropriate heat treatment technique, in particular the ductility properties are further increased. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. Thermo-Insulating Moulding Sand for thin Walled Castings

    Directory of Open Access Journals (Sweden)

    Cholewa M.

    2014-10-01

    Full Text Available In paper the selection of the composition and determination of main properties of novel moulding sand was described. The mail goal was to create moulding sand characterized by high thermal insulating properties in relations with low specific weight. This type of moulding sand will find application in thin walled castings with complex geometry, in particular for cores of the skeleton castings. In this work the results of the compressive strength, permeability and friability was presented. It was noted that aluminosilicate microspheres are suitable as moulding sand matrix. Influence of the polyglicol addition on quality and properties of the moulding sand was described. The use of the aluminosilicate microspheres allowed to obtain the moulding sand characterized by high insulation rate, low specific weight and good mechanical properties.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Prediction of Microporosity in Complex Thin-Wall Castings with the Dimensionless Niyama Criterion

    Science.gov (United States)

    Kang, Maodong; Gao, Haiyan; Wang, Jun; Ling, Lishibao; Sun, Baode

    2013-01-01

    The dimensionless Niyama criterion was used to predict the formation of microporosity in nickel-based superalloy casting, which extended the model application from a simple plate casting to complex thin-wall superalloy casting. The physical characteristics of the superalloy were calculated by JMatPro software. The relation between the volume percentage of microporosity and the dimensionless Niyama values were constructed. Quantitative metallographic measurements of the microporosity of the practical thin-wall casting were carried out. The prediction agreed well with the experiment in general, except for some thick-wall sites in the casting. PMID:28809243

  8. 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.

  9. Application of Hot Strength and Ductility Test to Optimization of Secondary Cooling System in Billet Continuous Casting Process

    Institute of Scientific and Technical Information of China (English)

    WANG Biao; JI Zhen-ping; LIU Wen-hong; MA Jiao-cheng; XIE Zhi

    2008-01-01

    By means of Gleeble-1500 dynamic thermomechanical simulator,the continuous casting process for HRB335C steel was simulated using solidifying method and hot ductility and strength of the steel were determined.The test results indicate that there are three temperature regions of brittleness for HRB335C billet in the temperature range from 700℃ to solidification point;the first temperature region of brittleness is 1 300℃ to solidification point of the billet,the second temperature region of brittleness is 1 200-1 000℃,and the third temperature region of brittleness is 700-850℃;the steel is plastic at 850-1 000℃.The cracking sensitivity was studied in the different temperature zones of the brittleness for steel HRB335C and the target surface temperature curve for the secondary cooling is determined.With optimized process,the mathematical model of the steady temperature field with two-dimensional heat transfer for 150 mm×150 mm HRB335C steel billet was established to optimize the secondary cooling process.The conic relation of water distribution between secondary cooling water flux and casting speed is regressed.Keeping the surface temperature of billet before the straightening point above 1 000℃,the results of billet test indicate that there is free central shrinkage cavity.The billet defect is decreased greatly,and the quality of billet is obviously improved.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Sclero-topometry Metrology in Valorisation of Waste Oil for Micro-machining of Ductile Cast Iron

    Directory of Open Access Journals (Sweden)

    Eymard S.

    2013-12-01

    Full Text Available During the time, the specific characteristics and the efficient lifetime of oil progressively decrease, due to complex pollution, ultimately making the oil unsuitable for the initial applications. The strategy to regenerate and to valorise waste oils is investigated using improved combinations of sclerometric and topometric tests on ductile nodular cast iron. Tribo-abrasive tests are performed in critical conditions, with base oil, waste oil and regenerated oil, of similar viscosities in order to discriminate their interfacial performances. The forms of the scratch traces indicate wear resistance and tendency to elasto-plastic deformation. The mechanisms of deformation and frictional behaviours were evaluated using optical and Scanning Electron Microscopy and measured for various tribological conditions with tactile and optical profilometry. The Energy Dispersive X ray Spectroscopy completes the chemical superficial distribution of pertinent elements. The surface topography metrology is used to characterize the scratch profiles and to determine the volume of the displaced and removed material, as well as maximum pit height. The originality of this paper is that it is a unique approach specifically devoted to transformer oil concerning tribological conditions.

  15. 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.

  16. 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.

  17. Role of Titanium in Thin Wall Vermicular Graphite Iron Castings Production

    Directory of Open Access Journals (Sweden)

    M. Górny

    2013-04-01

    Full Text Available In this paper the effects of titanium addition in an amount up to 0.13 wt.% have been investigated to determine their effect on the microstructure and mechanical properties of Thin Wall Vermicular Graphite Iron Castings (TWVGI. The study was performed for thinwalled iron castings with 3-5 mm wall thickness and for the reference casting with 13 mm. Microstructural changes were evaluated by analyzing quantitative data sets obtained by image analyzer and also using scanning electron microscope (SEM. Metallographic examinations show that in thin-walled castings there is a significant impact of titanium addition to vermicular graphite formation. Thinwalled castings with vermicular graphite have a homogeneous structure, free of chills, and good mechanical properties. It may predispose them as a potential use as substitutes for aluminum alloy castings in diverse applications.

  18. Solidified structure of thin-walled titanium parts by vertical centrifugal casting

    Directory of Open Access Journals (Sweden)

    Wu Shiping

    2011-05-01

    Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

  19. 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.

  20. Die Casting Mold Design of the Thin-walled Aluminum Case by Computational Solidification Simulation

    Institute of Scientific and Technical Information of China (English)

    Young-Chan Kim; Chang-Seog Kang; Jae-Ik Cho; Chang-Yeol Jeong; Se-Weon Choi; Sung-Kil Hong

    2008-01-01

    Recently, demand for the lightweight alloy in electric/electronic housings has been greatly increased. However, among the lightweight alloys, aluminum alloy thin-walled die casting is problematic because it is quite difficult to achieve sufficient fluidity and feedability to fill the thin cavity as the wall thickness becomes less than 1 mm. Therefore, in this study, thin-walled die casting of aluminum (Al-Si-Cu alloy: ALDC 12) in size of notebook computer housing and thickness of 0.8 mm was investigated by solidification simulation (MAGMA soft) and actual casting experiment (Buhler Evolution B 53D). Three different types of gating design, finger, tangential and split type with 6 vertical runners, were simulated and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt to flow into the thin cavity uniformly and split type gating system was preferable gating design comparing to tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. Also, the solidification simulation agreed well with the actual die-casting and the casting showed no casting defects and distortion.

  1. Thin-Wall Aluminum Die-Casting Technology for Development of Notebook Computer Housing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Silicon-based aluminum casting alloys are known to be one of the most widely used alloy systems mainly due to their superior casting characteristics and unique combination of mechanical and physical properties.However, manufacturing of thin-walled aluminum die-casting components, less than 1.0 mm in thickness, is generally known to be very difficult task to achieve aluminum casting alloys with high fluidity. Therefore, in this study, the optimal die-casting conditions for producing 297 mm×210 mm×0.7 mm thin-walled aluminum component was examined experimentally by using 2 different gating systems, tangential and split type, and vent design. Furthermore, computational solidification simulation was also conducted. The results showed that split type gating system was preferable gating design than tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. It was also found that proper vent design was one of the most important factors for producing thin-wall casting components because it was important for the fulfillment of the thin-wall cavity and the minimization of the casting distortion.

  2. Graphite nodules in fatigue-tested cast iron characterized in 2D and 3D

    DEFF Research Database (Denmark)

    Mukherjee, Krishnendu; Fæster, Søren; Hansen, Niels

    2017-01-01

    Thick-walled ductile iron casts have been studied by applying (i) cooling rate calculations by FVM, (ii) microstructural characterization by 2D SEM and 3D X-ray tomography techniques and (iii) fatigue testing of samples drawn from components cast in sand molds and metal molds. An analysis has shown...... correlations between cooling rate, structure and fatigue strengths demonstrating the benefit of 3D structural characterization to identify possible causes of premature fatigue failure of ductile cast iron....

  3. 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.

  4. 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...

  5. 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.

  6. Rapid precision casting for complex thin-walled aluminum alloy parts

    Directory of Open Access Journals (Sweden)

    Xuanpu DONG

    2004-11-01

    Full Text Available Based on Vacuum Differential Pressure Casting (VDPC precision forming technology and the Selective Laser Sintering (SLS Rapid Prototyping (RP technology, a rapid manufacturing method called Rapid Precision Casting (RPC process from computer three-dimensional solid models to metallic parts was investigated. The experimental results showed that the main advantage of RPC was not only its ability to cast higher internal quality and more accurate complex thin-walled aluminum alloy parts, but also the greatly-reduced lead time cycle from Selective Laser Sintering(SLS plastic prototyping to metallic parts. The key forming technology of RPC for complex thin-walled metallic parts has been developed for new casting production and Rapid Tooling (RT, and it is possible to rapidly manufacture high-quality and accurate metallic parts by means of RP in foundry industry.

  7. 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.

  8. Cast-in-place concrete thin-wall pipe pile as barrier for vibration isolation

    Institute of Scientific and Technical Information of China (English)

    张富有; 陈灿寿; 魏良甲; 张霆

    2008-01-01

    Three dimensional analysis was performed by regarding vibration isolation performance cast-in-place concrete thin-wall pipe pile (PCC) and using the finite element analysis software ANSYS. The ground vertical amplitude was analyzed behind the single row cast-in-place concrete thin-wall pipe pile after the source vibration, and the influencing factors were also studied. The results indicate that in the one time of wavelength before the barrier, the oscillation amplitude is weakened; meanwhile the range which covers 4 times wavelength behind the barrier has a good vibration isolation effect, when the distance is larger than the barrier latter 4 times wavelength vibration isolation expiration.

  9. 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...

  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. 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.

  12. 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.

  13. 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.

  14. Numerical simulation of mold-filling capability for a thin- walled aluminum die casting

    Science.gov (United States)

    Sun, L.; Subasic, E.; Jakumeit, J.

    2015-06-01

    Mold-filling capability is an important property of casting materials. Especially in thin-walled die casting, fast cooling of the melt by contact to the die makes complete filling difficult to ensure. Simulation is an important tool enabling investigation of filling problems, even before the die is manufactured. However, the prediction of misruns is challenging. Flow and solidification have to be computed as closely coupled. The effects of surface tension, the wetting angle and reduced melt flow due to solidification must be modeled with high precision. To meet these requirements, a finite-volume method using arbitrary polyhedral control volumes is used to solve flow and solidification as closely coupled. The Volume-of-Fluid approach is used to capture the phase separation between gas, melt and solid in connection with a High-Resolution Interface-Capturing scheme to obtain sharp interfaces between phases. To model the resistance of the dendrite network to the melt flow, an additional source term in the momentum equation was implemented. The Bolt test was performed for A356 alloys at a range of different casting temperatures. Numerical prediction of incomplete filling in the bottleneck regions agreed well with experimental findings using 3D camera scanning. The simulation enables derivation of the dependence of critical wall-thickness, i.e. the thickness which is fillable, on casting temperature and metallostatic pressure. This could prove useful in predicting filling problems ahead of casting.

  15. 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....

  16. Interfacial heat transfer in squeeze casting of magnesium alloy AM60 with variation of applied pressures and casting wall-thicknesses

    Science.gov (United States)

    Zhang, Xuezhi; Fang, Li; Sun, Zhizhong; Hu, Henry; Nie, Xueyuan; Tjong, Jimi

    2016-10-01

    The heat transfer coefficient at the casting-die interface is the most important factor on the solidification process. With the 75-ton hydraulic press machine and P20 steel die mold, 5-step castings of magnesium alloy AM60 with different wall-thicknesses (3, 5, 8, 12, 20 mm) were poured under various hydraulic pressures (30, 60, and 90 MPa) using an indirect squeeze casting process. Thermal histories throughout the die wall and the casting surface have been recorded by fine type-K thermocouples. The in-cavity local pressures measured by pressure transducers were explored at the casting-die interfaces of 5 steps. The casting-die interfacial heat transfer coefficients (IHTC) initially reached a maximum peak value followed by a gradually decline to the lower level. Similar characteristics of IHTC peak values can be observed at the applied pressures of 30, 60 and 90 MPa. With the applied pressure of 90 MPa, the peak IHTC values from steps 1 to 5 varied from 5623 to 10,649 W/m2 K. As the applied hydraulic pressure increased, the IHTC peak value of each step was increased accordingly. The wall thickness also affected IHTC peak values significantly. The peak IHTC value and heat flux increased as the step became thicker. The empirical equations relating the IHTCs to the local pressures and the solidification temperature at the casting surface were developed based on the multivariate linear and polynomial regression.

  17. 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.

  18. Predicting Stress vs. Strain Behaviors of Thin-Walled High Pressure Die Cast Magnesium Alloy with Actual Pore Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Sil; Barker, Erin; Cheng, Guang; Sun, Xin; Forsmark, Joy; Li, Mei

    2016-01-06

    In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to the experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results. This indicates that the developed 3D extrinsic modeling method may be used to examine the influence of various aspects of pore sizes/distributions as well as intrinsic properties (i.e., matrix properties) on the ductility/fracture of Mg castings.

  19. 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.

  20. A Study On Critical Thinning In Thin-walled Tube Bending Of Al-Alloy 5052O Via Coupled Ductile Fracture Criteria

    Science.gov (United States)

    Li, Heng; Yang, He; Zhan, Mei

    2010-06-01

    Thin-walled tube bending(TWTB) method of Al-alloy tube has attracted wide applications in aerospace, aviation and automobile,etc. While, under in-plane double tensile stress states at the extrados of bending tube, the over-thinning induced ductile fracture is one dominant defect in Al-alloy tube bending. The main objective of this study is to predict the critical wall-thinning of Al-alloy tube bending by coupling two ductile fracture criteria(DFCs) into FE simulation. The DFCs include Continuum Damage Mechanics(CDM)-based model and GTN porous model. Through the uniaxial tensile test of the curved specimen, the basic material properties of the Al-alloy 5052O tube is obtained; via the inverse problem solution, the damage parameters of both the two fracture criteria are interatively determined. Thus the application study of the above DFCs in the TWTB is performed, and the more reasonable one is selected to obtain the critical thinning of Al-alloy tube in bending. The virtual damage initiation and evolution (when and where the ductile fracture occurs) in TWTB are investigated, and the fracture mechanisms of the voided Al-alloy tube in tube bending are consequently discussed.

  1. 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)

  2. 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.

  3. 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.

  4. 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 ...

  5. 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.

  6. Effect of Different Molding Materials on the Thin-Walled Compacted Graphite Iron Castings

    Science.gov (United States)

    Górny, Marcin; Dańko, Rafał; Lelito, Janusz; Kawalec, Magdalena; Sikora, Gabriela

    2016-10-01

    This article addresses the effects of six mold materials used for obtaining thin-walled compacted graphite iron castings with a wall thickness of 3 mm. During this research, the following materials were analyzed: fine silica sand, coarse silica sand, cerabeads, molohite and also insulated materials in the shape of microspheres, including low-density alumina/silica ceramic sand. Granulometric and SEM observations indicate that the sand matrix used in these studies differs in terms of size, homogeneity and shape. This study shows that molds made with insulating sands (microspheres) possess both: thermal conductivity and material mold ability to absorb heat, on average to be more than five times lower compared to those of silica sand. In addition to that, the resultant peak of heat transfer coefficient at the mold/metal interface for microspheres is more than four times lower in comparison with fine silica sand. This is accompanied by a significant decrease in the cooling rate of metal in the mold cavity which promotes the development of compacted graphite in thin-walled castings as well as ferrite fractions in their microstructure.

  7. Large structural, thin-wall castings made of metals subject to hot tearing, and their fabrication

    Science.gov (United States)

    Smashey, Russell W. (Inventor)

    2001-01-01

    An article, such as a gas turbine engine mixer, is made by providing a mold structure defining a thin-walled, hollow article, and a base metal that is subject to hot tear cracking when cast in a generally equiaxed polycrystalline form, such as Rene' 108 and Mar-M247. The article is fabricated by introducing the molten base metal into the mold structure, and directionally solidifying the base metal in the mold structure to form a directionally oriented structure. The directionally oriented structure may be formed of a single grain or oriented multiple grains.

  8. 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.

  9. 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)

  10. Advanced casting technologies for lightweight automotive applications

    Directory of Open Access Journals (Sweden)

    Alan A. Luo

    2010-11-01

    Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

  11. LATE MODIFYING IS AN EFFECTIVE WAY OF THE CAST IRON CRYSTALLIZATION CONTROL AT PRODUCTION OF THIN-WALLED CASTING

    Directory of Open Access Journals (Sweden)

    S. P. Korolev

    2006-01-01

    Full Text Available It is shown that application of special modifiers allowed to carry out effective late graphitizing modification, which provided elimination of border chill in thin castings of complex configuration in terms of mass production.

  12. 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)

  13. Development of pressure control system in counter gravity casting for large thin-walled A357 aluminum alloy components

    Institute of Scientific and Technical Information of China (English)

    LI Xin-lei; HAO Qi-tang; JIE Wan-qi; ZHOU Yu-chuan

    2008-01-01

    Counter gravity casting equipments(CGCE) were widely used to produce large thin-walled A357 aluminum alloy components. To improve the pressure control precision of CGCE to get high quality castings, a pressure control system based on fuzzy-PID hybrid control technology and the digital assembled valve was developed. The actual pressure tracking experiment results show that the special system by applying PID controller and fuzzy controller to varied phases, is not only able to inherit the small error and good static stability of classical PID control, but also has fuzzy control's advantage of fully adapting itself to the object. The pressure control error is less than 0.3 kPa. By using this pressure control system, large complex thin-walled A357 aluminum alloy castings with high quality was successfully produced.

  14. A novel approach to mapping load transfer from the plantar surface of the foot to the walls of the total contact cast: a proof of concept study

    Directory of Open Access Journals (Sweden)

    Begg Lindy

    2012-12-01

    Full Text Available Abstract Background Total contact casting is regarded as the gold standard treatment for plantar foot ulcers. Load transfer from the plantar surface of the foot to the walls of the total contact cast has previously been assessed indirectly. The aim of this proof of concept study was to determine the feasibility of a new method to directly measure the load between the cast wall and the lower leg interface using capacitance sensors. Methods Plantar load was measured with pedar® sensor insoles and cast wall load with pliance® sensor strips as participants (n=2 walked along a 9 m walkway at 0.4±0.04 m/sec. The relative force (% on the cast wall was calculated by dividing the mean cast wall force (N per step by the mean plantar force (N per step in the shoe-cast condition. Results The combined average measured load per step upon the walls of the TCC equated to 23-34% of the average plantar load on the opposite foot. The highest areas of load on the lower leg were located at the posterior margin of the lateral malleolus and at the anterior ankle/extensor retinaculum. Conclusions These direct measurements of cast wall load are similar to previous indirect assessment of load transfer (30-36% to the cast walls. This new methodology may provide a more comprehensive understanding of the mechanism of load transfer from the plantar surface of the foot to the cast walls of the total contact cast.

  15. Injection-moulded models of major and minor arteries: the variability of model wall thickness owing to casting technique.

    Science.gov (United States)

    O'Brien, T; Morris, L; O'Donnell, M; Walsh, M; McGloughlin, T

    2005-09-01

    Cardiovascular disease of major and minor arteries is a common cause of death in Western society. The wall mechanics and haemodynamics within the arteries are considered to be important factors in the disease formation process. This paper is concerned with the development of an efficient computer-integrated technique to manufacture idealized and realistic models of diseased major and minor arteries from radiological images and to address the issue of model wall thickness variability. Variations in wall thickness from the original computer models to the final castings are quantified using a CCD camera. The results found that wall thickness variation from the major and minor idealized artery models to design specification were insignificant, up to a maximum of 16 per cent. In realistic models, however, differences were up to 23 per cent in the major arterial models and 58 per cent in the minor arterial models, but the wall thickness variability remained within the limits of previously reported wall thickness results. It is concluded that the described injection moulding procedure yields idealized and realistic castings suitable for use in experimental investigations, with idealized models giving better agreement with design. Wall thickness is variable and should be assessed after the models are manufactured.

  16. INVESTIGATION OF THE INFLUENCE OF MOLD ROTATIONAL SPEED ON THE CAST WALL THICKNESS IN THE ROTATIONAL MOLDING PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Jachowicz

    2013-09-01

    Full Text Available This paper presents the rotational molding process. The general principles of this polymer processing technology have been described. The main applications have been introduced and leading advantages and typical disadvantages of rotational molding process have been discussed. Based on the conducted experimental tests, the influence of changing one selected technological parameter, which characterized rotational molding process, on selected geometrical features of the polymer cast has been determined. Rotational mold’s speed around axes was changed and a thickness of cast walls has been measured. Laboratory test stand, processing properties of polymer, also test program and experimental test methodology have been described.

  17. 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.

  18. 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...

  19. Development of casting process for large thin-wall precision magnesium alloy castings%大型薄壁精密镁合金铸件铸造技术进展

    Institute of Scientific and Technical Information of China (English)

    王艳光; 彭晓东; 赵辉; 谢卫东; 魏群义

    2011-01-01

    The advantage and disadvantage as well as the development of sand casting, low tension casting, die casting, lost foam casting and centrifugal casting technologies for the production of large thin - wall precision magnesium alloy castings are discussed. According to the development of aerospace industry, the research and development direction of the magnesium alloy centrifugal casting are pointed out.%介绍了砂型、低压、压铸、消失模、离心铸造大型、薄壁、精密镁合金铸件的优势和缺点,以及这些铸造技术的最新发展情况.针对航天工业的发展指出离心铸造镁合金的研究与发展方向.

  20. Thermomechanical treatment of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    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

  1. 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.

  2. 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.

  3. 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 ...

  4. Evaluation of nano ceramic coating on radiographic defects of thin-walled AL4-4 aluminum alloy sand casting

    Directory of Open Access Journals (Sweden)

    Mansour Borouni

    2016-10-01

    Full Text Available Internal defects are among the problems in gravity casting of aluminum parts. The main internal volumetric defects are gas and shrinkage defects which form during solidification of the melt and drastically reduce the quality of the produced parts. These defects adversely affect the mechanical properties of thin walled castings parts. In this study, ceramic nanoparticles coatings were applied on the sand mold and the effect of mold coatings on the reduction of defects were investigated. X-ray radiography was used to detect defects in sand molds with ceramic nanoparticles coatings. For comparison, this test was performed on molds with micro-ceramic and graffiti coatings and uncoated sand mold. The results showed that the maximum amount of gas and shrinkage defects was observed in casting parts from AL4-1 alloy in uncoated molds. On the other hand, the minimum defects were found in molds coated with ceramic nanoparticles. It seems that the reduced defects in casting parts in molds coated with ceramic nanoparticles may be due to high thermal and chemical stability and higher heat transfer rate of the coating. These results can facilitate the production of high quality aluminum alloys parts using nanotechnology.

  5. Modeling of Mold Filling and Solidification in Lost Foam Casting

    Institute of Scientific and Technical Information of China (English)

    Fengjun LI; Houfa SHEN; Baicheng LIU

    2003-01-01

    Based on the characteristics of the lost foam casting (LFC) and the artificial neural network technique, a mathematicalmodel for the simulation of the melt-pattern interface movement during the mold filling of LFC has been proposed andexperimentally verified. The simulation results are consistent with the experiments in both the shapes of melt frontand filling sequences. According to the calculated interface locations, the fluid flow and the temperature distributionsduring the mold filling and solidification processes were calculated, and the shrinkage defect of a lost foam ductileiron casting was predicted by considering the mold wall movement in LFC. The simulation method was applied tooptimize the casting design of lost foam ductile iron castings. It is shown that the model can be used for the defectsprediction and for casting design optimization in the practical LFC production.

  6. 铝合金薄壁件真空吸铸充型能力的研究%Research on Filling Capacity of Vacuum Suction Casting for Thin-Walled Aluminum Alloy Castings

    Institute of Scientific and Technical Information of China (English)

    李剑; 郝启堂; 李新雷; 陈云龙

    2012-01-01

    Filling capacity is an important factor affecting the forming of vacuum suction casting thin-walled castings. The filling capacity of vacuum suction casting was compared with the low-pressure casting by pouring sheet casting of aluminum alloys. Furthermore, the effects of vacuum level, filling speed and wall thickness on filling capacity in vacuum suction casting were researched. Due to the lower counter pressure in mold, the filling capacity of vacuum suction casting is the best among the investigated casting methods. In addition, the increase of vacuum and filling speed is helpful to increase the filling capacity of antigravity aluminum alloy casting, and the increase range is closely related to the wall thickness.%充型能力是影响真空吸铸薄壁铸件成形生产的重要因素.本研究通过铝合金薄板件的浇注试验,对比了真空吸铸和低压铸造的充型能力差异,研究了真空吸铸条件下真空度大小、充型速度及壁厚对充型能力的影响规律.结果表明:真空吸铸具有优良的充型能力,较低的型内反压是充型能力提高的主要原因;此外,真空度和充型速度的增大有助于提高反重力浇注铝合金薄壁件的充型能力,提高幅度与壁厚有密切关系.

  7. 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.

  8. A Banding Structure in a Ni-Cu-Si Cast Alloy

    Institute of Scientific and Technical Information of China (English)

    Qi ZHENG; Yufeng ZHENG; Hongyu ZHANG; Xiaofeng SUN; Hengrong GUAN; Zhuangqi HU

    2008-01-01

    The solidified microstructure of a Ni-Cu-Si cast alloy has been investigated, and a kind of banding structure was observed. The results showed that, the banding structure was composed of coarser particles which were Ni3Si type of precipitates and similar to the fine particles precipitate uniformly distributed within matrix of Ni solid solution, in both crystal structure and composition. The formation of bandings was resulted from cast thermal stress and dislocation walls. It was found that the cracks propagated along these bandings in tensile test. The banding structure can be depressed by reducing the cast thermal stress, which can improve the Qtensile ductility.

  9. FIELD DEMONSTRATION OF EMERGING PIPE WALL INTEGRITY ASSESSMENT TECHNOLOGIES FOR LARGE CAST IRON WATER MAINS

    Science.gov (United States)

    The U.S. Environmental Protection Agency sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,500-ft long, cement-lined, 24-in. cast iron water main in Louisville, KY from July through Septembe...

  10. Design of reinforced concrete walls casted in place for the maximum normal stress of compression

    Directory of Open Access Journals (Sweden)

    T. C. Braguim

    Full Text Available It is important to evaluate which designing models are safe and appropriate to structural analysis of buildings constructed in Concrete Wall system. In this work it is evaluated, through comparison of maximum normal stress of compression, a simple numerical model, which represents the walls with frame elements, with another much more robust and refined, which represents the walls with shells elements. The designing of the normal stress of compression it is done for both cases, based on NBR 16055, to conclude if the wall thickness initially adopted, it is enough or not.

  11. Clinical evaluation of internal axial wall divergence in inlays and casting post-and-core fabrication

    Directory of Open Access Journals (Sweden)

    Min-Chieh Hsieh

    2015-06-01

    Conclusion: Compared with the teeth preparation of external axial wall in a single crown, the sighted distance at 30-cm distance in the internal axial wall is 1.5 × wider. More sighted distances are required to prevent undesired undercuts.

  12. Preparation and properties of multi-wall carbon nanotube/SiC composites by aqueous tape casting

    Institute of Scientific and Technical Information of China (English)

    L(U) ZhiHui; JIANG DongLiang; ZHANG JingXian; LIN QingLing

    2009-01-01

    MWCNTS/SiC composites were fabricated by aqueous tape casting. High solid content (50 vol%) SiC slurries with sintering additives and multi-wall carbon nanotubes (MWCNTs) as reinforcements were prepared using Tetramethylammonium hydroxide as the dispersant. The stability of MWCNTs/SiC slur-ries was studied and characterized in terms of zeta potential and rheology measurements. The relative density of the composite was about 98% after hot-pressing at 1850℃ (at 25 MPa in Ar for 30 min). The hardness of the composites decreased with the increase in MWCNTs content, The flexural strength and was 0,25 wt%. Further increase in MWCNTs content to 0.50 wt% did not lead to the increase in me-chanical properties. Most of MWCNTs were found to be located at SiC grain boundaries and the pull out of the MWCNTs was observed.

  13. 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.

  14. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Lost Foam Thin Wall - Feasibility of Producing Lost Foam Castings in Aluminum and Magnesium Based Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fasoyinu, Yemi [CanmetMATERIALS; Griffin, John A. [University of Alabama - Birmingham

    2014-03-31

    With the increased emphasis on vehicle weight reduction, production of near-net shape components by lost foam casting will make significant inroad into the next-generation of engineering component designs. The lost foam casting process is a cost effective method for producing complex castings using an expandable polystyrene pattern and un-bonded sand. The use of un-bonded molding media in the lost foam process will impose less constraint on the solidifying casting, making hot tearing less prevalent. This is especially true in Al-Mg and Al-Cu alloy systems that are prone to hot tearing when poured in rigid molds partially due to their long freezing range. Some of the unique advantages of using the lost foam casting process are closer dimensional tolerance, higher casting yield, and the elimination of sand cores and binders. Most of the aluminum alloys poured using the lost foam process are based on the Al-Si system. Very limited research work has been performed with Al-Mg and Al-Cu type alloys. With the increased emphasis on vehicle weight reduction, and given the high-strength-to-weight-ratio of magnesium, significant weight savings can be achieved by casting thin-wall (≤ 3 mm) engineering components from both aluminum- and magnesium-base alloys.

  15. 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.

  16. Construction-friendly ductile shear joints for precast concrete panels

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Fischer, Gregor

    2015-01-01

    The scope of this paper is the shear capacity of in-situ cast joints between precast concrete panels. Current practice with vertical lowering of the wall panels experiences difficulties in the assembly phase, since the traditional U-bar connection requires an overlap in a horizontal plane to allow...... a construction-friendly design with U-bars overlapping in the same plane as the panel itself. The design allows for a trouble-free vertical lowering of the panels without pre or post processing of the preinstalled reinforcement loops. Furthermore, an overall more ductile behavior of the joint is obtained....... The solution is tested in a push-off experimental setup and the influence of important geometric parameters of the keyed shear joint is investigated. The first peak load carrying capacity is assessed using plasticity models, and the failure modes are identified by the use of digital image correlation...

  17. 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.

  18. Analysis of Heat-and-Mass Transfer Conjugated Problem Solution while Forming Thin-Wall Castings

    Directory of Open Access Journals (Sweden)

    R. I. Еsman

    2009-01-01

    Full Text Available The paper contains an analysis of heat-and-mass transfer conjugated problem in case of moving of liquid melts in channels of metallic forms (moulds, dies, crystallizers etc.. Investigations of velocity profiles at various flow sections, current lines in the calculated area, pressure and viscosity fields in non-stationary state have been carried out in the paper.The paper reveals that current is of parabolic shape in the annular channel at rather large distance from a projection up and down the flow and pressure along channel section is practically unchangeable.The executed investigations of heat-and-mass transfer in the moving melt make it possible to create a data base of control parameters for development of prospective technologies  of special casting methods. 

  19. Attachment of Alumina on the Wall of Submerged Entry Nozzle During Continuous Casting of Al-Killed Steel

    Science.gov (United States)

    Deng, Zhiyin; Zhu, Miaoyong; Zhou, Yelian; Sichen, Du

    2016-06-01

    The mechanisms of the formation of different attachments on the walls of submerged entry nozzle (SEN) were studied for the processes of Al-killed steel (Ca-treated, HSLA) and ultra-low carbon Al-killed steel (ULC). To understand the mechanism, the types of inclusions in the steel taken in tundish and in bloom (or slab) were identified. In the case of ULC, the reoxidation product, micro-alumina particles were found to be the source of attachment on the inner wall of the SEN. To avoid reoxidation of the steel by the top slag, removal of the slag could be considered in order to improve the situation. No attached layer was found on the outer surface of the SEN after casting of the ULC steel. In the case of HSLA steel, an attached layer composed of plate-like alumina crystals was found in some trials. The entrainment of oxygen through the mold powder due to improper operation would be the reason for the formation of this type of attachment. The formation of the plate-like crystals was discussed with the help of CFD calculation.

  20. The ancient Chinese casting techniques

    Directory of Open Access Journals (Sweden)

    Tan Derui

    2011-02-01

    Full Text Available In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast iron, ductile cast iron, brass, cupronickel alloy (Packtong, etc. According to their surface decorative techniques they can be devided into gem inlay, gilding, gold and silver inlay, copper inlay, engraved decoration, surface tin-enrichment, mother-of-pearl inlay, burnished works with gold or silver inlay, surface coloring and cloisonné enamel, etc.

  1. 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...

  2. Improvement of Process Design of Lost Foam Casting for Thin-walled Tall Steel Casting%薄壁高大铸钢件消失模铸造工艺的改进

    Institute of Scientific and Technical Information of China (English)

    杨彦芳; 卢献忠; 范晓明

    2015-01-01

    The heavy rail bearing of thin-walled tall steel castings were produced by the use of lost foam casting. But the problems such as 'vacant shell', collapse of sand and so on,which lead to the lower quality and yield of castings. By improving the casting process, using bottom pouring system to replace the ladder pouring system,using sprue and runner of refractory materials, reducing pouring temperature and degree of negative pressure, and adopting appropriate pouring speed, the quality and yield of heavy rail bearing steel castings were successfully improved. The experience of production is worth promoting.%利用消失模铸造工艺生产了薄壁高大铸钢重轨支座,出现了“空壳”、塌箱等问题,导致其质量和成品率较低。通过改进铸造工艺,改阶梯浇注为底部浇注,采用耐火材料直浇道和横浇道,降低浇注温度和负压度,并采用合适的浇注速度,成功提高了重轨支座铸钢件的质量和成品率,其生产经验值得推广。

  3. 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

  4. Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors

    Science.gov (United States)

    Chiou, Jin-Chern; Wu, Chin-Cheng; Huang, Yu-Chieh; Chang, Shih-Cheng; Lin, Tse-Mei

    2016-01-01

    This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT) composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C) via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC), polyethylene oxide (PEO), and polyvinylpyrrolidone (PVP). Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM) morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC) testing. PMID:28025507

  5. Preparation and properties of multi-wall carbon nanotube/SiC composites by aqueous tape casting

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    MWCNTS/SiC composites were fabricated by aqueous tape casting. High solid content (50 vol%) SiC slurries with sintering additives and multi-wall carbon nanotubes (MWCNTs) as reinforcements were prepared using Tetramethylammonium hydroxide as the dispersant. The stability of MWCNTs/SiC slur-ries was studied and characterized in terms of zeta potential and rheology measurements. The relative density of the composite was about 98% after hot-pressing at 1850℃ (at 25 MPa in Ar for 30 min). The hardness of the composites decreased with the increase in MWCNTs content. The flexural strength and the fracture toughness were 742.17 MPa and 4.63 MPa·m1/2, respectively when the MWCNTs content was 0.25 wt%. Further increase in MWCNTs content to 0.50 wt% did not lead to the increase in mechanical properties. Most of MWCNTs were found to be located at SiC grain boundaries and the pull out of the MWCNTs was observed.

  6. Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors

    Directory of Open Access Journals (Sweden)

    Jin-Chern Chiou

    2016-12-01

    Full Text Available This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC, polyethylene oxide (PEO, and polyvinylpyrrolidone (PVP. Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC testing.

  7. Cast-in-place concrete walls: thermal comfort evaluation of one-storey housing in São Paulo State

    Directory of Open Access Journals (Sweden)

    H. M. Sacht

    Full Text Available This paper presents a proposal of thermal performance evaluation of a one-storey housing typology (TI24A executed by CDHU - Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo, considering the use of cast-in-place monolithic panels of concrete, with different thicknesses panels (8, 10 and 12 cm and density between 1600 and 2400 kg/m³. In this study, the specific purpose was discussing the influence of the characteristic of concrete walls on the housing thermal performance without slab. Was defined of first parameters of study (definition of the one-storey housing typology, survey about housing users behavior and cities choose and executed computational simulation (winter and summer, for four São Paulo State cities (São Paulo, São Carlos, Santos e Presidente Prudente, with the software Arquitrop 3.0 in a one-storey housing. Was observed that in winter and summer the typologies analyzed, the panels thickness variation had more influence about results than different concrete densities. The minimum level of thermal performance (M in winter has been granted for some cities, with exception of Santos. In summer one of São Paulo city’s typology was attended the minimum level of thermal performance in agreement with standard “NBR 15575 Residential buildings up to five storied - Performance, Part 1: General requirements”.

  8. 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.

  9. Die-casting Process for High-performance Thin-wall Casting of Aluminum Alloy%高性能薄壁铝合金铸件的压铸

    Institute of Scientific and Technical Information of China (English)

    尹志鹏; 宋朝辉; 李义平

    2016-01-01

    采用本公司发明的专利技术制备了铝合金浆料。概述了高性能薄壁多抽芯铝合金铸件的半固态流变压铸生产过程。经半固态流变压铸生产的铝合金铸件的显微组织致密,无气孔、缩松和夹杂,T6热处理后的力学性能比普通压铸件提高了40%左右。%Aluminum alloy paste was fabricated with a patent technology invented by Cixi Alt Advanced Materials Co.. The semi-solid rheocasting process for high-performance multi-core thin-wall aluminum alloy castings was outlined. The aluminum alloy castings produced by the semi-solid rheologic die-casting technology exhibited dense structure in which there are not any pore, porosity and inclusion, and after being T6 treated its mechanical properties were 40% higher that of common die castings.

  10. 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...

  11. 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.

  12. Microstructure and mechanical properties of in situ casting TiC/Ti6Al4V composites through adding multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ya, Bin; Zhou, Bingwen; Yang, Hongshuo; Huang, Bingkun; Jia, Fei; Zhang, Xingguo, E-mail: zxgwj@dlut.edu.cn

    2015-07-15

    Highlights: • Adding MWCNTs in situ casting fabricating TiC/Ti6Al4V composites is first reported. • The solidification process of in situ casting TiC/Ti6Al4V composites is discussed. • Microstructure shows remarkable correlations with adding MWCNTS. • Strength and plasticity show remarkable correlations with adding MWCNTs. - Abstract: In this study, multi-walled carbon nanotubes (MWCNTs) were added as carbon sources to fabricate in situ casting TiC/Ti6Al4V (TC4) composites. The effects of MWCNTs on the microstructure and mechanical properties are studied. The composites are analyzed by X-ray diffraction, field-emission scanning electron microscope and electron probe microanalysis. The fracture behavior of TiC/TC4 composites are also studied. Smaller size of TiC particles and grain compared with TC4-graphite composites can be observed. The tensile strength of TC4-MWCNTs composites is about 1110.1 MPa, which is higher than that of TC4-graphite composites, about 1003.6 MPa. Fracture behavior also was changed by adding MWCNTs in situ casting TiC/TC4 composites.

  13. 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.

  14. 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.

  15. Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Denslow, Kayte M.; Diaz, Aaron A.; Doctor, Steven R.

    2007-03-01

    Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz synthetic aperture focusing technique and phased array technology applied at 500 kHz, 750 kHz, and 1.0 MHz. Flaw detection and characterization on the welded specimens was performed with the phased array method operating at the frequencies stated above. This report documents the methodologies used and provides results from laboratory studies to assess baseline material noise, crack detection, and length-sizing capability for low-frequency UT in cast stainless steel piping.

  16. 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.

  17. Optimization of Mold Yield in MultiCavity Sand Castings

    Science.gov (United States)

    Shinde, Vasudev D.; Joshi, Durgesh; Ravi, B.; Narasimhan, K.

    2013-06-01

    The productivity of ductile iron foundries engaging in mass production of castings for the automobile and other engineering sectors depends on the number of cavities per mold. A denser packing of cavities, however, results in slower heat transfer from adjacent cavities, leading to delayed solidification, possible shrinkage defects, and lower mechanical properties. In this article, we propose a methodology to optimize mold yield by selecting the correct combination of the mold box size and the number of cavities based on solidification time and mold temperature. Simulation studies were carried out by modeling solid and hollow cube castings with different values of cavity-wall gap and finding the minimum value of the gap beyond which there is no change in casting solidification time. Then double-cavity molds were modeled with different values of cavity-cavity gap, and simulated to find the minimum value of gap. The simulation results were verified by melting and pouring ductile iron in green sand molds instrumented with thermocouples, and recording the temperature in mold at predetermined locations. The proposed approach can be employed to generate a technological database of minimum gaps for various combinations of part geometry, metal and process, which will be very useful to optimize the mold cavity layouts.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. Green-sand casting process improvement of high silicon molybdenum ductile iron connector%高硅钼球铁连接件的潮模砂铸造工艺改进

    Institute of Scientific and Technical Information of China (English)

    赵黎甲

    2016-01-01

    分析了铸件产生缩松、砂孔等铸造缺陷的原因,通过结合生产实际的经验,制定了该类零件铸造工艺的优化改进措施。实施证明,铸件的缩松、砂孔缺陷得到消除,提高了该类铸件的合格率和出品率,降低了生产成本,有极高的经济效益,并可广泛使用。%Analysis are conducted on the root causes of casting defects such as shrinkage porosity and sand inclusion and measures are worked out to improve and optimize the casting process for the part based on the actual production experience. Through implementation it proves that defects of shrinkage porosity and sand inclusion are eliminated and conformity and yield rate of the castings have been improved, and cost has been reduced as well. The method has been approved to have high economic beneift and can be widely used.

  5. Development of Vacuum Lost Foam-Investment Shell Mould Composite Casting Process Used for Ductile Iron Pipes Production%球铁管件真空消失模壳型复合铸造工艺的研究

    Institute of Scientific and Technical Information of China (English)

    符坚; 龙枚青; 符寒光

    2012-01-01

    The advantages and disadvantages of the vacuum lost foam fasting process and the investment casting process were compared- By combining two processes flexibly,a composite process consisted of vacuum lost foam process plus investment shell mould process and useable for large scale production of high property pipe castings was developed. An introduction was given to the determ illation of the rigidity of the lost foam pattern, dimensions choice of the gating system, establishment of the shell mould making process flow, the choice and preparation of the raw materials of shell mould,as well as the sodium silicate shell mould making process (low. The test result showed: (a )When using above process for the pipes production,the operation procedure was easy and the easting quality was stable with the casting pass rate higher than 98.5% ; (b )This process needs only making 4 layers of mould shells,much less than that of the normal investment casting process which needs making 8 and even more layers of mould shells.and therefore,the productivity was enhanced,both the. production cost and the labors cost were reduced.%比较了真空消失模铸造和熔模铸造两种工艺的优缺点,将两种工艺的优点有机结合,开发了适应大量生产高性能出口管件的真空消失模壳型复合铸造工艺.介绍了消失模铸造模型刚度的确定、浇注系统尺寸的选择,壳型工艺流程的制订、壳型涂料的原材料选用和配制、以及水玻璃壳型制造流程.试验结果显示:(1)用此工艺生产的管件,工序简单且铸件质最稳定,铸件合格率达到98.5%以上;(2)此工艺只要制4层壳,相比普通蜡模精密铸造制壳要8层以上,提高了生产效率,降低了生产成本和人力资源成本.

  6. 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

  7. 现浇轻质保温复合墙体施工技术%Construction of Cast-in-place Lightweight Thermal Insulation Composite Wall

    Institute of Scientific and Technical Information of China (English)

    黄旭腾; 杨庆泽

    2014-01-01

    Cast-in-situ lightweight composite insulation wall is erected with light steel keel and ce-ment pressure plate, pouring molding with the new lightweight rigid insulation materials. The new lightweight rigid insulation materials consist of a large amount of tailings, fly ash, boron mud and other in-dustrial waste as the main raw material for recycling. The wall technology with light steel keel in construc-tion industry, horizontal transfer and infiltration of the technical content are researched for determining the construction of cast-in-situ light composite insulation wall, enhancing technology of green environmental protection and energy saving, reducing waste emissions, solving environmental pollution, saving the land resources with good economic benefit and social benefit.%现浇轻质保温复合墙体是利用轻钢龙骨和水泥压力板支模后,现场浇入新型轻质刚性保温材料而制成的一次成型复合墙体,其中新型轻质刚性保温材料是以大量尾矿粉、粉煤灰、硼泥等工业废弃物作为主要原材料,通过可回收再利用,实现变废为宝。通过建筑行业轻钢龙骨墙体施工工艺,横向转移和渗透其技术内容,研究确定现浇轻质保温复合墙体的施工技术,推广应用绿色环保节能技术,减少废弃物排放,解决环境污染问题,节约土地资源,具有良好的经济效益和社会效益。

  8. Manufacturing of High Ductility Aluminum Bronze Porcelain Sleeve Flange by Centrifugal Casting%高塑性铝铁青铜瓷套法兰离心铸造工艺

    Institute of Scientific and Technical Information of China (English)

    王清宇

    2012-01-01

    介绍了铝铁青铜材料的特性以及瓷套法兰铸件的使用状况和力学性能要求.在生产过程中应用了离心铸造工艺,通过分析生产中易产生的缺陷及防止措施的实施,制定了合理的高塑性铝铁青铜铸件离心铸造生产工艺,并通过生产过程的控制,达到了生产优质合格瓷套法兰零件的目的.%The characteristics of aluminum bronze material, using conditions and requirement for mechanical properties of porcelain sleeve flange were expounded. The porcelain sleeve flamge was produced by centrifugal casting. Through analyzing defects and implementing measures for eliminating defects, the proper centrifugal casting process was presented. By controlling strictly production process, the qualified porcelain sleeve flange was produced successfully.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Solidification of cast iron - A study on the effect of microalloy elements on cast iron

    DEFF Research Database (Denmark)

    Moumeni, Elham

    The present thesis deals with the heat transfer and solidification of ductile and microalloyed grey cast iron. Heterogeneous nucleation of nodular graphite at inclusions in ductile iron during eutectic solidification has been investigated. A series of ductile iron samples with two different...... of the austenite, in the last region to solidify. The superfine graphite which forms in this type of irons is short (10-20µm) and stubby. The microstructure of this kind of graphite flakes in titanium alloyed cast iron is studied using electron microscopy techniques. The methods to prepare samples of cast iron...... for comprehensive transmission electron microscopy of graphite and the surrounding iron matrix have been developed and explained. Dual beam microscopes are used for sample preparation. A TEM study has been carried out on graphite flakes in grey cast iron using selected area electron diffraction (SAED). Based...

  14. 77 FR 22562 - Non-Malleable Cast Iron Pipe Fittings From the People's Republic of China: Initiation and...

    Science.gov (United States)

    2012-04-16

    ... Administration regarding the Final Scope Ruling on Black Cast Iron Cast, Green Ductile Flange and Twin Tee... and to release any cash deposit or bond.\\5\\ The current requirement for a cash deposit of estimated AD...

  15. 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.

  16. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  17. 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...

  18. 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.

  19. 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...

  20. 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.

  1. Pulmonary hyperinflation and respiratory distress following solvent aspiration in a patient with asthma: expectoration of bronchial casts and clinical improvement with high-frequency chest wall oscillation.

    Science.gov (United States)

    Koga, Toshihiko; Kawazu, Taketoshi; Iwashita, Kazuo; Yahata, Ritsuko

    2004-11-01

    An 18-year-old student with a history of asthma accidentally inhaled organic solvent during a class, with immediate cough and dyspnea that worsened over several hours. He presented in severe respiratory distress, with hypoxemia and marked pulmonary hyperinflation. Administration of inhaled bronchodilator was ineffective because of agitation, and the patient could not be positioned for chest physiotherapy to treat presumed widespread mucus plugging. High-frequency chest wall oscillation (HFCWO) in the sitting position initially caused increased distress but was subsequently tolerated when noninvasive positive-pressure ventilation (NPPV) via nasal mask was initiated. Almost immediately, the patient began expectorating bronchial mucus casts, with concomitant clinical improvement. Endotracheal intubation was avoided, and with aggressive pharmacologic treatment for acute severe asthma and continuation of intermittent HFCWO-NPPV, the patient made a full recovery over the next several days. This case suggests that the combination of HFCWO and NPPV may be helpful in the presence of mucus plugging as a complication of acute inhalation injury or acute severe asthma.

  2. Manufacturing of Thin-walled Al-Mg Food Machinery by Permanent Mold Gravity Casting%食品机械薄壁件铝镁合金重力铸造工艺

    Institute of Scientific and Technical Information of China (English)

    王明沧; 许正华

    2011-01-01

    Large thin-walled Al-Mg alloy housing for food machinery was usually produced by green sand casting or semi-permanent mold integrating with semi-green sand mold casting because of the easy occurrence of hot crack of Al-Mg alloy in permanent mold. A tilting gravity casting was presented to eliminate the problems in permanent mold casting. Considering mould design and adjusting the pouring parameters, large thin-walled Al-Mg alloy housing was produced successfully by permanent mold gravity casting. The practical production shows that the technology can be widely used to produce thin-walled parts or easily-hot crack alloy parts.%由于Al-Mg合金金属型铸造易产生热裂,在生产食品机械外壳大型薄壁铸件时,多以湿砂型或半金属型-半湿砂型方式生产.针对金属型工艺生产大型薄壁铸件比较困难的问题,提出一种倾转式重力铸造工艺,结合模具设计、浇注参数的调整,实现了全金属型大型Al-Mg台金薄壁铸件的生产.实践证明,本工艺可广泛应用于薄壁铸件或易产生热裂合金铸件的生产.

  3. 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...

  4. 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.

  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. Microcosmic analysis of ductile shearing zones of coal seams of brittle deformation domain in superficial lithosphere

    Institute of Scientific and Technical Information of China (English)

    JU; Yiwen; WANG; Guiliang; JIANG; Bo; HOU; Quanlin

    2004-01-01

    The ductile shearing zones of coal seams in a brittle deformation domain in superficial lithosphere are put forward based on the study on bedding shearing and ductile rheology of coal seams. The macrocosmic and microcosmic characteristics include wrinkle fold, mymonitized zones and ductile planar structure of coal seams, etc., while the microcosmic characteristics may also include different optic-axis fabrics and the anisotropy of vitrinite reflectance as well as the change of chemical structure and organic geochemistry components. The forming mechanism is analyzed and the strain environment of ductile shearing zones of coal seams discussed. The result indicates that, in the superficial brittle deformation domain, the coal seams are easy to be deformed, resulting in not only brittle deformation but also ductile shearing deformation under the action of force. Because of simple shearing stress, the interlayer gliding or ductile rheology may take place between coal seams and wall rocks. Therefore, many ductile shearing zones come into being in superficial lithosphere (<5 km). The research on ductile shearing zone of brittle deformation domain in superficial lithosphere is significant not only theoretically for the study of ductile shearing and ductile rheology of the lithosphere but also practically for the structural movement of coal seams, the formation and accumulation of coal-bed methane, and the prevention and harness of gas burst in coal mine.

  7. Rare Earth Additions in Continuously Cast Steel

    Science.gov (United States)

    Wilson, William G.; Heaslip, L. J.; Sommerville, I. D.

    1985-09-01

    Rare earth (lanthanide metals) addiiions to continuously cast steel are particularly advantageous because of their ability to refine as-cast structures, reduce segregation and increase hot ductility at temperatures just below that of solidification. The complete shape control of sulfides in steels containing Rare Earth Metals (REM), whether continuously cast or ingot cast, is primarily responsible for improvements in ductility related mechanical properties, weldability, fatigue resistance and resistance to hydrogen damage. Complete sulfide shape control can be obtained with REM additions at sulfur levels as high as.020%. The greatest improvements, however, are obtained with REM additions to low sulfur steels. However, to achieve full operational advantages afforded by REM, nozzle blockage problems must be circumvented. Water model studies indicate a possible solution.

  8. 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.

  9. Cast iron - a predictable material

    Directory of Open Access Journals (Sweden)

    Jorg C. Sturm

    2011-02-01

    Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

  10. 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.

  11. Calorimetric examinations of austempered ductile iron ADI

    Directory of Open Access Journals (Sweden)

    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.

  12. The Silumin Coat Structure on Alloy Ductile Iron

    Directory of Open Access Journals (Sweden)

    Szymczak T.

    2013-03-01

    Full Text Available The work presents the research results of the silumin coat structure applied on the carbidic alloy ductile iron with the metal matrix: pearlitic, bainitic and martensitic. The coats were made in the AlSi5 silumin bath at the temperature tk = 750±5°C. The holding time of cast iron element in the bath was τ = 180s. Irrespective of the kind of tested ductile iron the obtained coat consisted of three layers with a different phase composition. The first layer from the cast iron ground “g1`” is built from Fe4CSi carbide which contains selected alloy additives of the cast iron. On it the second layer “g1``” crystallizes. It consists of the AlFeSi inter-metallic phase which can appear in its pure form or contain a small quantity of the alloy additives of the cast iron. The last external part of the layer “g2” mainly consists of the hypo-eutectic phases of silumin. The AlFeSi inter-metallic phases in the form of free precipitations with a lamellar or faceted morphology can also appear there. These phases also can contain a small quantity of the alloy additives of the cast iron. More than that, in all the layers of the coat there are graphite precipitations. The phenomenon of graphite movement to the coat is caused by intensive dissolving of the cast iron element surface by the aluminum of the silumin bath.

  13. Theory of batchwise centrifugal casting

    NARCIS (Netherlands)

    Biesheuvel, P. Maarten; Nijmeijer, Arian; Verweij, Henk

    1998-01-01

    In batchwise centrifugal casting a cylindrical mold is filled with suspension and rotated rapidly around its axis. This results in the movement of the particulate phase toward the cylinder wall and the formation of a tubular cast. Theory is presented for particle transport in the suspension phase an

  14. 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 ...

  15. 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...

  16. 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.

  17. 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).

  18. 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.

  19. 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.

  20. 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.

  1. Analysis Strategy for Fracture Assessment of Defects in Ductile Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dillstroem, Peter; Andersson, Magnus; Sattari-Far, Iradj; Weilin Zang (Inspecta Technology AB, Stockholm (Sweden))

    2009-06-15

    The main purpose of this work is to investigate the significance of the residual stresses for defects (cracks) in ductile materials with nuclear applications, when the applied primary (mechanical) loads are high. The treatment of weld-induced stresses as expressed in the SACC/ProSACC handbook and other fracture assessment procedures such as the ASME XI code and the R6-method is believed to be conservative for ductile materials. This is because of the general approach not to account for the improved fracture resistance caused by ductile tearing. Furthermore, there is experimental evidence that the contribution of residual stresses to fracture diminishes as the degree of yielding increases to a high level. However, neglecting weld-induced stresses in general, though, is doubtful for loads that are mostly secondary (e.g. thermal shocks) and for materials which are not ductile enough to be limit load controlled. Both thin-walled and thick-walled pipes containing surface cracks are studied here. This is done by calculating the relative contribution from the weld residual stresses to CTOD and the J-integral. Both circumferential and axial cracks are analysed. Three different crack geometries are studied here by using the finite element method (FEM). (i) 2D axisymmetric modelling of a V-joint weld in a thin-walled pipe. (ii) 2D axisymmetric modelling of a V-joint weld in a thick-walled pipe. (iii) 3D modelling of a X-joint weld in a thick-walled pipe. t. Each crack configuration is analysed for two load cases; (1) Only primary (mechanical) loading is applied to the model, (2) Both secondary stresses and primary loading are applied to the model. Also presented in this report are some published experimental investigations conducted on cracked components of ductile materials subjected to both primary and secondary stresses. Based on the outcome of this study, an analysis strategy for fracture assessment of defects in ductile materials of nuclear components is proposed. A new

  2. Mechanical properties of homogenized twin-roll cast and conventionally cast AZ31 magnesium alloys

    Directory of Open Access Journals (Sweden)

    Mariia Zimina

    2015-02-01

    Full Text Available The improvement of mechanical properties of magnesium alloys nowadays is very important, because of the variety of industrial applications. For this goal, the number of casting techniques and further treatments were developed. Among the continuous casting techniques, which allow producing long strips of the alloys, is twin-roll casting. Using this process one can get the magnesium alloy with finest microstructure and higher specific strength. In this paper the comparison of tensile properties of conventionally cast and twin-roll cast AZ31 magnesium alloys was made. Tensile tests were carried out with constant strain rate 10-3 s-1 at temperatures ranging from 100 to 300 °C. Both materials were tested in as-cast state and after homogenization treatment at 450 °C for 10 hours. The investigation showed that there are no significant changes in ductility of AZ31 conventionally cast alloy even after heat treatment, while the ductility of twin-roll cast alloy increases.

  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. Ductility Performance of Hybrid Fibre Reinforced Concrete

    OpenAIRE

    S. Eswari; P.N. Raghunath; Suguna, K

    2008-01-01

    This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to...

  5. Effects of homogenisation treatment on microstructure and hot ductility of aluminium alloy 6063

    Energy Technology Data Exchange (ETDEWEB)

    Couto, K.B.S.; Claves, S.R.; Geetruyden, W.H. van; Misiolek, W.Z.; Goncalves, M.

    2005-02-15

    Several homogenisation treatments were applied to direct chill (DC) cast ingots of aluminium alloy 6063, in order to analyse the resulting microstructures developed from these diverse conditions and their effects on the hot ductility of this alloy. Imaging was performed using scanning electron microscopy (SEM) and a focused ion beam (FIB) instrument. These techniques identified variations in distribution and morphology of second phase particles (AlFeSi and Mg{sub 2}Si). FIB results for the various AlFeSi particles correctly identify their shapes in three dimensions (3D). The particles were identified by energy dispersive spectroscopy (EDS) in the SEM, and by X-ray diffraction (XRD) for bulk samples. Hot tensile testing (HTT) was conducted between 470 and 600 deg C to asses the hot ductility for each condition. The inferior ductility of as cast samples was due to the poor bond strength of the {beta} AlFeSi phase at the grain boundaries. Homogenised samples, which contain {alpha} AlFeSi, exhibited improved ductility. Samples that were water quenched following homogenisation were absent of Mg{sub 2}Si precipitates, when these elements remained in solid solution. These exhibited the highest ductility. (Author)

  6. 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 %.

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

    Directory of Open Access Journals (Sweden)

    SHU Xin-fu

    2005-11-01

    Full Text Available Both the production process and the chemical composition of Sx were studied, and the serialization of low 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 %.

  8. 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.

  9. 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.

  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. 现浇磷石膏墙体研究及性能试验分析%RESEARCH AND PERFORMANCE TEST ANALYSIS OF CAST-IN-PLACE PHOSPHOGYPSUM WALL

    Institute of Scientific and Technical Information of China (English)

    卢亚琴; 张华刚; 罗玚; 梁凡凡; 马克俭

    2014-01-01

    基于现浇磷石膏在住宅结构应用的研究现状及施工工艺,将磷石膏与磷渣粉、熟石灰和水泥混合成干物料,并掺入减水剂和缓凝剂加水搅拌,制作试件研究其抗压强度、放射性、凝结时间和含水率等基本性能。材料配合比9组,共制作27个立方体试件。抗压强度试验表明:现浇磷石膏墙体的抗压强度标准值在2.5~11.0 MPa之间,强度设计值可按0.478的标准值采用,完全可作框架填充墙及低层小开间住宅承重墙使用;另外,缓凝剂掺量对现浇磷石膏墙体抗压强度影响显著。基于推荐配合比的磷石膏试件的检测表明,现浇磷石膏墙体的初凝时间为45 min,终凝时间为55 min,能满足现场浇筑工艺要求;放射性检测结果符合国家标准对建筑主材放射性的要求;墙体5d的含水率为2.6%,基本能达到干燥状态。%It is described the research on cast-in-place phosphogypsum for residential structure and the summary of construction technology according to the engineering practice .Phosphogypsum , phosphorus slag power , slaked lime and cement are mixed into dry material , and then water reducing agent , retarder and water are added to stir , and 27 cube specimens considering 9 kinds of mixture ratio are made to test the compressive strength and radioactive and setting time and moisture content etc .The compressive strength tests show that the standard values of compressive strength of cast-in-place phosphogypsum wall are between 2.5~11.0 MPa, the strength design values can be 0.478 times of the standard values , and the phosphogypsum can be used for the filled walls of frame structure and the load -bearing walls of lower small bay residential houses .The volume of the retarder has an obvious effect on the compressive strength of cast-in-place phosphogypsum wall .The detection of the specimens show that the initial setting time and final setting time of cast

  12. DESIGN SOLUTIONS FOR THERMAL INSULATION OF EXTERIOR WALLS OF CAST-IN-PLACE CONCRETE HIGH-RISE RESIDENTIAL BUILDINGS IN CENTRAL REGIONS OF СHINA

    Directory of Open Access Journals (Sweden)

    Bantserova Ol'ga Leonidovna

    2012-12-01

    Full Text Available A significant portion of the overall heat loss is due to the heat loss through the building envelope. According to the opinions of experts, the surface area of exterior walls has the insulation of about 65 % of the total envelope of apartment buildings; therefore, thermal protection of external walls of buildings is a key issue in ensuring the thermal performance of envelopes of apartment buildings. The author has developed design solutions that assure the thermal protection of exterior walls and that are aimed at identifying the optimal solution in terms of the location of insulation materials, their thermal performance and insulation of exterior walls of apartment buildings in central regions of China. The author presents a comparative analysis of the main methodologies of thermal insulation designated for the exterior walls of multi-storey residential buildings: internal and external insulation, as well as the insulation in-between the wall layers. The analyses of wall designs are based on the insulation performance, thermal insulation performance, methods of mounting different systems of insulation, and cost of work. As a result, practical recommendations originate from the statement that the most optimal designs of exterior walls of monolithic high-rise apartment buildings of central regions of China are those that have insulation on the outside of the building. They include layers of insulation made of extruded polystyrene, which is currently planned for use in the construction of high-rise monolithic residential buildings in central China.

  13. 大口径厚壁钢管热模法离心铸造机的设计与应用%Design and Application of A Centrifugal Casting Machine with Hot Die for Large Caliber Steel Pipt with Thick Wall

    Institute of Scientific and Technical Information of China (English)

    习杰

    2011-01-01

    详细介绍了采用热模法离心铸造厚壁钢管坯的设计思路,以及该机主要机构(等量浇注装置、主机、推管机构等)的设计.%Design idea of a centrifugal casting machine with hot die for large caliber steel pipt with thick wall has been introduced in details with design of the main equipment such as pouring device with dosing device, main machine and pipe ejector etc., hence a typical instance of application of centrifugal casting technology on forming of pipe with thick wall.

  14. APPLICATION OF MODIFYING ALLOYING ALLOY CONTAINING NANOSIZED POWDERS OF ACTIVE ELEMENTS IN PRODUCTION OF HIGH-STRENGTH CAST IRON WITH GLOBULAR GRAPHITE

    Directory of Open Access Journals (Sweden)

    A. S. Kalinichenko

    2015-01-01

    Full Text Available Scientific and practical interest is the application of alloying alloy-modifiers for secondary treatment of high-strength cast iron to stabilize the process of spheroidization graphite and achieving higher physical-mechanical properties of castings. The peculiarity of the high-strength cast irons manufacturing technology is their tendency to supercooling during solidification in the mold. This leads to the formation of shrinkage defects and structurally free cementite, especially in thin-walled sections of the finished castings. To minimize these effects in foundry practice during production of ductile iron the secondary inoculation is widely used. In this regard, the question of the choice of the additives with effective impact not only on the graphitization process but also on the formation of the metallic base of ductile iron is relevant. The aim of the present work is to study the peculiarities of structure formation in cast iron with nodular graphite when alloying alloy-modifier based on tin with additions of nanoparticles of titanium carbide, yttrium oxide and graphite nano-pipes is used for secondary treatment. Melting of iron in laboratory conditions was performed in crucible induction furnace IST-006 with an acid lining held. Spheroidizing treatment of melt was realized with magnesium containing alloying alloy FeSiMg7 by means of ladle method. Secondary treatment of high strength cast iron was carried out by addition of alloying alloy-modifier in an amount of 0.1% to the bottom of the pouring ladle. Cast samples for chemical composition analysis, study of microstructure, technological and mechanical properties of the resultant alloy were made. Studies have shown that the secondary treatment of high strength cast iron with developed modifier-alloying alloy results in formation of the perlite metallic base due to the tin impact and nodular graphite with regular shape under the influence of titanium carbide, yttrium oxide and graphite nano

  15. Research Progress of Precision Casting of Large Complex Thin-walled Titanium Alloy%大型复杂钛合金薄壁件精铸成形技术研究进展

    Institute of Scientific and Technical Information of China (English)

    赵瑞斌

    2015-01-01

    Large complex thin-walled titanium alloy precision casting is the most advanced technologies in the world of military and civil aviation field.This paper introduces its process flow, technical features and the domestic and international research frontier achievements. Combined with the most popular international computer numerical simulation and 3D print and other new technology, summarizes the research trend and development direction of this technology in China: theory research strengthen of the investment casting process, research of titanium alloy design and exploration of large thin wall complex higher performance of casting titanium alloy, construction of model library, development of automatic coating machine slurry and sanding process, better quality management and control of the whole process, more emphasis on application of 3D printing technology in the fields of the manufacture and investment casting process of titanium alloy.%大型复杂薄壁钛合金精密铸造技术是当今世界军用与民用航空领域的尖端技术。介绍了熔模精密铸造技术的工艺流程、技术特点以及国内外研究现状。结合国际最流行的计算机数值模拟以及3D打印等新型技术,指出我国该项技术的研究趋势与发展方向是:①加强熔模铸造工艺的理论研究;②深化钛合金设计研究,探索性能更高的适合于大型复杂薄壁件铸造成形的钛合金;③深入研究纯净化技术,以及夹杂和铸造缺陷与性能之间的定量关系;④建立型壳模型库;⑤研发机器自动涂浸浆料与撒砂工艺;⑥加强全过程的质量管理与控制;⑦高度关注3D打印技术在钛合金制造领域的发展及其在钛合金熔模铸造领域的应用。

  16. Caste System

    OpenAIRE

    Hoff, Karla

    2016-01-01

    In standard economics, individuals are rational actors and economic forces undermine institutions that impose large inefficiencies. The persistence of the caste system is evidence of the need for psychologically more realistic models of decision-making in economics. The caste system divides South Asian society into hereditary groups whose lowest ranks are represented as innately polluted. ...

  17. Repair, Evaluation, Maintenance, and Rehabilitation Research Program. Comparison of Cast-in-Place Concrete Stay-in-Place Forming Systems for Lock Wall Rehabilitation

    Science.gov (United States)

    1993-10-01

    primarily to restraint of volume changes resulting from shrinkage, thermal gradients, and autogenous volume changes. In most cases, such cracking will not...for drainage and the horizontal joints are filled by infill concrete placement. River wall panel layout includes 1/2-in.-vertical joints and l/2-in...was removed and the infill concrete sawcut to full depth. Vertical joints were then left open to aid in the drainage of any seepage through the walls. a

  18. 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.

  19. U 型现浇配筋混凝土薄壁空心装饰柱施工技术%On construction technique of U-shaped cast-in-place reinforced concrete thin-wall hollow decoration columns

    Institute of Scientific and Technical Information of China (English)

    姚国荣

    2015-01-01

    The paper describes the craft features for the U-shaped cast-in-place reinforced concrete thin-wall hollow decoration columns,illus-trates the construction craft procedure and material requirements by combining with its construction craft principle,and researches the construc-tion quality,safety and environment protection control measures,so as to achieve better economic and social benefits.%描述了 U 型现浇配筋混凝土薄壁空心装饰柱施工的工艺特点,结合其施工工艺原理,阐述了施工工艺流程及材料要求,并对施工质量、安全、环保控制措施进行了研究,以取得良好的经济、社会效益。

  20. 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

  1. Optimal scaling in ductile fracture

    Science.gov (United States)

    Fokoua Djodom, Landry

    This work is concerned with the derivation of optimal scaling laws, in the sense of matching lower and upper bounds on the energy, for a solid undergoing ductile fracture. The specific problem considered concerns a material sample in the form of an infinite slab of finite thickness subjected to prescribed opening displacements on its two surfaces. The solid is assumed to obey deformation-theory of plasticity and, in order to further simplify the analysis, we assume isotropic rigid-plastic deformations with zero plastic spin. When hardening exponents are given values consistent with observation, the energy is found to exhibit sublinear growth. We regularize the energy through the addition of nonlocal energy terms of the strain-gradient plasticity type. This nonlocal regularization has the effect of introducing an intrinsic length scale into the energy. We also put forth a physical argument that identifies the intrinsic length and suggests a linear growth of the nonlocal energy. Under these assumptions, ductile fracture emerges as the net result of two competing effects: whereas the sublinear growth of the local energy promotes localization of deformation to failure planes, the nonlocal regularization stabilizes this process, thus resulting in an orderly progression towards failure and a well-defined specific fracture energy. The optimal scaling laws derived here show that ductile fracture results from localization of deformations to void sheets, and that it requires a well-defined energy per unit fracture area. In particular, fractal modes of fracture are ruled out under the assumptions of the analysis. The optimal scaling laws additionally show that ductile fracture is cohesive in nature, i.e., it obeys a well-defined relation between tractions and opening displacements. Finally, the scaling laws supply a link between micromechanical properties and macroscopic fracture properties. In particular, they reveal the relative roles that surface energy and microplasticity

  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. Investigation of Ductility Reduction Factor in Seismic Rehabilitation of Existing Reinforced Concrete School Buildings

    Directory of Open Access Journals (Sweden)

    O. Gorgulu

    2015-02-01

    Full Text Available Converting existing Reinforced Concrete (RC frames into RC infill walls is one of the most efficient seismic strengthening technique due to its simplicity in application providing high rigidity, stability and strength in structures. On the other hand, this method affects the seismic behavior of existing RC structure in terms of the energy dissipation capacity or in other words, ductility reduction factor, Rμ. This research is an attempt to investigate the RC infill wall ratio effect on ductility reduction factor in terms of the seismic rehabilitation of the typical RC school buildings. For this purpose, nonlinear static pushover analyses are conducted for existing 3 and 5 story RC school buildings which were rehabilitated with different RC infill wall ratio. Numerical analyses are carried out by using the fiber element based modeling approach in the software, Perform-3D. Based on these analytical results, correlation between the ductility reduction factor and the RC infill wall ratio is obtained for the seismic rehabilitation of the RC school buildings. In addition, two mathematical expressions for the variation of the ductility reduction factor with RC infill wall ratios are proposed in terms of the preliminary seismic rehabilitation assessment of the existing RC school buildings.

  4. 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

  5. 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.

  6. Strategies for improving ductility of ordered intermetallics

    Institute of Scientific and Technical Information of China (English)

    Z.B. Jiao; J.H.Luan; C.T.Liu

    2016-01-01

    Ordered intermetallics possess attractive high-temperature properties; however, low ductility and brittle fracture limit their use as engineering materials in many cases. This paper provides a comprehensive review on the recent progress in the development of ductile ordered intermetallics and summarizes the strategies used to improve the tensile ductility of ordered intermetallics, including control of ordered crystal structures, engineering grain-boundary structure and chemistry, eliminating environmental embrittlement, microstructure optimization, control of phase stability, and promoting transformation-/twining-induced plasticity. The basic ideas and related mechanisms underlying these ductilizing strategies are discussed. In addition, a brief mention of the current use of intermetallic alloys for structural and corrosion applications is made.

  7. Hair casts

    Directory of Open Access Journals (Sweden)

    Sweta S Parmar

    2014-01-01

    Full Text Available Hair casts or pseudonits are circumferential concretions,which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis.

  8. 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

  9. 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...

  10. Properties shaping and repair of selected types of cast iron

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2007-04-01

    Full Text Available The paper presents research results of twofold use of TIG - Tungsten Inert Gas also known as GTA - Gas Tungsten Arc. First is surfacing by welding on cold and hot-cold to repair chromium cast iron with chromium content about 15%. Second is remelting with electric arc of selected gray (with pearlitic matrix and ductile (with ferritic-pearlitic matrix cast iron. Repair of cast iron elements was realized in order to cut out a casting defects. Defects decrease a usability of castings for constructional application and increase a manufacturing costs. Application of surface heat treatment guarantees mechanical properties i.e. hardness and wear resistance improvement. The result of investigations show possibility of castings repair by put on defects a good quality padding welds, which have comparable properties with base material. Use of electric arc surface heat treatment resulted in increase of hardness and wear resistance, which was measured on the basis of ASTM G 65 - 00 standard.

  11. Solidification and casting

    CERN Document Server

    Cantor, Brian

    2002-01-01

    INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo

  12. Characterization of Ni–Cr alloys using different casting techniques and molds

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Teng, Fu-Yuan [Department of Dentistry, Kaohsiung Armed Forces General Hospital, Kaohsiung 802, Taiwan (China); School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Hung, Chun-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China)

    2014-02-01

    This study differentiated the mechanical properties of nickel–chromium (Ni–Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni–Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, “casting mold,” significantly influenced all mechanical properties. The graphite mold casting of the Ni–Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni–Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. - Highlights: • Properties of Ni–Cr alloys using various casting techniques are characterized. • Alloys cast by graphite mold exhibited higher recovery angle and more ductility. • Alloys cast by graphite mold exhibited higher strength and grinding rate. • Alloys in this study increase operative room to adjust the precision for prosthesis.

  13. 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.

  14. 外加剂对脱硫石膏制备现浇墙体材料性能影响%Effect of Additive on Desulfurization Gypsum Cast-in-place Wall Material

    Institute of Scientific and Technical Information of China (English)

    武丽霞; 李冬; 任彦茹

    2015-01-01

    In order to broaden the usage of desulfurization gypsum, and fulfill the directly use of it, Monosodium glutamate was selected as retarder, poly carboxylic acid was selected as reducing agent, effects of which on desulfurization gypsum cast-in-place wall material were studied. Desul-furization gypsum was prebaked for 2 hours at 55℃, and then burned for 3 hours at 160℃, the standard consistency water demand was determined according to GB/T 17669.4-1999. The experi-ment results were as follows:with adding 3%Monosodium glutamate as retarder, 0.5%Poly carbo-xylic acid as reducing agent, and initial setting time of desulfurization gypsum cast-in-place wall material is about 54 min and final setting time extends to 96 min, which meet the requirements of construction. Dry flexural strength of the wall material is 3.31 MPa, dry compressive strength is 12.27 MPa.%为了拓宽我国脱硫石膏的利用途径,实现对脱硫石膏直接利用,本研究选取谷氨酸钠作为缓凝剂,聚羧酸作为减水剂,对脱硫石膏现浇墙体材料进行改性研究。试验结果表明:电厂的脱硫石膏经过55℃预烘干2 h,160℃烘干3 h,按照GB/T 17669.4-1999确定标稠需水量,添加3%谷氨酸钠作为缓凝剂,0.5%聚羧酸作为减水剂时,现浇墙体材料的初凝时间约54 min,终凝时间延长至96 min,复配后初终凝时间满足施工要求;墙体材料的绝干抗折强度为3.31 MPa,绝干抗压强度为12.27 MPa。

  15. CENTRIFUGAL CASTING OF ANTIFRICTION SILUMIN

    Directory of Open Access Journals (Sweden)

    V. Ju. Stetsenko

    2010-01-01

    Full Text Available It is shown that the way of centrifugal casting into water-cooled mould with vertical rotation axis enables to receive hollow slugs with diameter 100–250 mm, with height under 200 mm with wall thickness under 15 mm of antifriction silumin АК15М3, which will replace expensive antifriction bronze.

  16. Ductile failure X-prize.

    Energy Technology Data Exchange (ETDEWEB)

    Cox, James V.; Wellman, Gerald William; Emery, John M.; Ostien, Jakob T.; Foster, John T.; Cordova, Theresa Elena; Crenshaw, Thomas B.; Mota, Alejandro; Bishop, Joseph E.; Silling, Stewart Andrew; Littlewood, David John; Foulk, James W., III; Dowding, Kevin J.; Dion, Kristin; Boyce, Brad Lee; Robbins, Joshua H.; Spencer, Benjamin Whiting

    2011-09-01

    Fracture or tearing of ductile metals is a pervasive engineering concern, yet accurate prediction of the critical conditions of fracture remains elusive. Sandia National Laboratories has been developing and implementing several new modeling methodologies to address problems in fracture, including both new physical models and new numerical schemes. The present study provides a double-blind quantitative assessment of several computational capabilities including tearing parameters embedded in a conventional finite element code, localization elements, extended finite elements (XFEM), and peridynamics. For this assessment, each of four teams reported blind predictions for three challenge problems spanning crack initiation and crack propagation. After predictions had been reported, the predictions were compared to experimentally observed behavior. The metal alloys for these three problems were aluminum alloy 2024-T3 and precipitation hardened stainless steel PH13-8Mo H950. The predictive accuracies of the various methods are demonstrated, and the potential sources of error are discussed.

  17. Characterization of Ni-Cr alloys using different casting techniques and molds.

    Science.gov (United States)

    Chen, Wen-Cheng; Teng, Fu-Yuan; Hung, Chun-Cheng

    2014-02-01

    This study differentiated the mechanical properties of nickel-chromium (Ni-Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni-Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, "casting mold," significantly influenced all mechanical properties. The graphite mold casting of the Ni-Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni-Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. 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.

  19. 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.

  20. Energetic approach for ductile tearing; Approche energetique de la dechirure ductile

    Energy Technology Data Exchange (ETDEWEB)

    Marie, St

    1999-07-01

    This study focuses on ductile crack initiation and propagation. It aims to propose an approach for the engineer allowing the prediction of the evolution of cracks in large scale components, from parameters determined on laboratory specimens. A crack initiation criterion, defining a J{sub i} tenacity related to crack tip blunting proposed in the literature is validated in the study. This criterion is shown to be transferable from laboratory specimens to structures. The literature review shows that an approach based on the dissipated energy in the fracture process during propagation offers an economical and simple solution to simulate large crack growth. A numerical method is proposed to estimate this fracture energy. The existence of an energy parameter G{sub fr} is shown, by simulating the propagation by the simultaneous release of several elements and by the use of the Rice integral with an original integration path. This parameter represents the needed energy for a unit crack extension and appears to be intrinsic to the material. A global energy statement allows to relate this parameter to a variation of the plastic part of J integral. It offers a second numerical method to simulate the propagation just from stationary numerical calculations, as well as the elaboration of a simplified method. This approach, using two parameters J{sub i} and G{sub fr}, intrinsic to the material and experimentally measurable on specimens, is validated on many tests such as crack pipes subjected to four points bending and cracked rings in compression. For example, this approach allows to model up to 90 mm ductile tearing in a pipe with a circumferential through-wall crack in ferritic steel, or to anticipate the evolution of a semi-elliptical crack in an aged austenitic ferritic steel plate subjected to bending. (author)

  1. Vacuum-sealed casting process under pressure

    Institute of Scientific and Technical Information of China (English)

    LI Chen-xi; GUO Tai-ming; WU Chun-jing; WANG Hong

    2006-01-01

    A new casting method, the vacuum-sealed mold casting under pressure, has been developed, and thin wall iron castings with high precision and smooth surface have been produced successfully with this casting method. The experimental results show that the liquid iron has a very excellent filling ability because a high negative pressure is formed in the mold cavity during filling process. The vacuum-sealed mold under pressure has very high compressive strength greater than 650 kPa, which is 3-4 times as high as that of the molds produced by high-pressure molding process or vacuum-sealed molding process.

  2. Experiments on Hybrid Precast Concrete Shear Walls Emulating Monolithic Construction with Different Amounts of Posttensioned Strands and Different Debond Lengths of Grouted Reinforcements

    Directory of Open Access Journals (Sweden)

    Zhangfeng Zhu

    2016-01-01

    Full Text Available This paper proposed a hybrid precast concrete shear wall emulating monolithic construction (HPWEM that utilized grouted vertical connecting reinforcements and unbonded posttensioned high-strength strands across the horizontal joint for the lateral resistance. The grouted reinforcements with predetermined debond length were used to provide strength by tension and energy dissipation by yielding. The posttensioned strands were mainly employed to offer the restoring force to reduce the residual displacement by elastic extension. The overlapping welded closed stirrups improved the confinement property of the restrained concrete, avoiding the brittle failure. Six HPWEM specimens, considering variables including the amounts of strands and the debond lengths of grouted reinforcements, as well as one referenced cast-in-place monolithic wall specimen, were tested under the low-cycle reversed lateral load. The HPWEM specimens were capable of providing strength, stiffness, ductility, and energy dissipation equivalent to that of the monolithic wall specimen under certain variable condition.

  3. 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.

  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. 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.

  6. A Novel Process in Semi-Solid Metal Casting

    Institute of Scientific and Technical Information of China (English)

    Bijan Abbasi-Khazaei; Saeid Ghaderi

    2012-01-01

    In this research a new process for semi-solid casting of ductile iron based on the high nucleation rate combined with locally mechanical stirring is presented. In this process at first fully liquid ductile iron was poured on the peripheral surface of a wheel rotating against pouring direction. At this stage, the solid crystals nucleated at the chilling surface were pushed to the melt by a heat resistance steel cutter and finally the semi-solid slurry was generated. Reheating treatment was done on the samples to achieve more efficiency of semi-solid casting process. The effects of the travelling distance of solid particles during casting, the reheating time and temperature were examined. The results showed that the process effectively changes the dendrite structure to globular one.

  7. Ductility Performance of Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    S. Eswari

    2008-01-01

    Full Text Available This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to study the above parameters. The specimens incorporated 0.0 to 2.0% volume fraction of polyolefin and steel fibres in different proportions. The ductility performance of hybrid fibre reinforced concrete specimens was compared with that of plain concrete. The test results show that addition of 2.0% by volume of hybrid fibres improves the ductility performance appreciably. An adaptive Neuro-Fuzzy based model has been proposed to predict the ductility performance characteristics. A reasonably close agreement has been obtained between the experimental and predicted results.

  8. 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.)

  9. Chilling Tendency and Chill of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    E. Fra(s); M. Górny; W. Kapturkiewicz; H. López

    2008-01-01

    An analytical expression is presented for the susceptibility of liquid cast iron to solidify according tothe Fe-C-X metastable system (also known as the chilling tendency of cast iron, CT). The analysis incorpo-rates the nucleation and growth processes associated with the eutectic transformation. The CT is related tothe physicochemical state of the liquid, the eutectic cells in the flake graphite, and the number of nodules innodular cast iron. In particular, the CT can be related to the critical wall thickness, Scr, or the chill width, Wcr,in wedge shaped castings. Finally, this work serves as a guide for understanding the effect of technical fac-tors such as the melt chemistry, the spheroidizing and inoculation practice, and the holding time and tam-perature on the resultant CT and chill of the cast iron. Theoretical calculations of Scr and Wcr compare wellwith experimental data for flake graphite and nodular cast iron.

  10. "Work-Hardenable" ductile bulk metallic glass.

    Science.gov (United States)

    Das, Jayanta; Tang, Mei Bo; Kim, Ki Buem; Theissmann, Ralf; Baier, Falko; Wang, Wei Hua; Eckert, Jürgen

    2005-05-27

    Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (< 1%) at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive "work hardening" and large ductility of 18%. Significant increase in the flow stress was observed during deformation. The "work-hardening" capability and ductility of this class of metallic glass is attributed to a unique structure correlated with atomic-scale inhomogeneity, leading to an inherent capability of extensive shear band formation, interactions, and multiplication of shear bands.

  11. Non-net casting exterior thermal insulation system on field concrete exterior wall in high storeyed resident building%高层住宅现浇混凝土外墙无网浇合外保温体系

    Institute of Scientific and Technical Information of China (English)

    顾同曾; 夏祖宏; 邸占英

    2001-01-01

    The non - net casting exterior thermal insulation system on field concrete exterior wall in high storeyed resident building is developed firstly at home. This system adopts polystyrene board without steel wire net as thermal insulation board. The cracking resistant layer consists of polymer cement mortar and alkali resistant glass fiber woven scrim, anchored with plastic expanded tube. The tests of bonding power between polystyrene board and concrete, plastic expanded tube pull- out, compressibility, freeze resistance show the system property is reliable and high safe. The thermal measurement test shows the system can meet the requirement of wall body energy - saving 50% stipulated in Beijing "Energy Saving Detailed Regulations", with low construction cost and high work efficiency. The comprehensive construction cost lowers 40%~50% in comparison with back suspending net system.%在国内首次开发了高层住宅现浇混凝土外墙无网浇合外保温体系。该体系采用无钢丝网架的聚苯板为保温板,抗裂层由聚合物水泥砂浆及耐碱玻纤网格布组成,再用塑料胀管锚固。经聚苯板与混凝土粘合力、塑料胀管抗拔力、压缩率及抗冻试验表明该体系性能可靠、安全度高;热工测试表明满足北京市《节能细则》对墙体节能50%的要求;造价低、工效高,综合造价比后挂有网体系降低40%~50%。

  12. Nodular cast iron and casting monitoring

    OpenAIRE

    2008-01-01

    In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  13. Nodular cast iron and casting monitoring

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2008-10-01

    Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  14. 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.

  15. 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.

  16. 49 CFR 192.277 - Ductile iron pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Ductile iron pipe. 192.277 Section 192.277 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Ductile iron pipe. (a) Ductile iron pipe may not be joined by threaded joints. (b) Ductile iron pipe may...

  17. Effects of Cr Content and Annealing Temperature on Microstructure and Wear Characteristics of Cast Ausferrite Nodular Iron

    Institute of Scientific and Technical Information of China (English)

    Jia-peng ZOU; Kazumichi SHIMIZU; Qi-zhou CAI

    2015-01-01

    The effects of Cr content and annealing temperature on abrasive wear characteristics of cast ausferrite nodular iron were investigated with Suga type abrasive wear tester. The surface morphology and Vickers hardness of the tested samples were analyzed by scanning electron microscopy (SEM), digital microscope and Vickers hardness tester. The results show that the cast ausferrite nodular iron could be obtained by alloying with Cr in the as-cast ductile cast iron and permanent mold casting, and the bainite con-tent in the matrix increased with increasing Cr content. However, the decomposition of bainite took place during annealing at 500 °C to 800 °C; especially, at 800 °C, the bainite transformed into a mixture of ifne lamellar pearlite and ferrite matrix structure. The wear loss of specimens was reduced with increasing Cr content in the cast ausferrite nodular iron. The wear loss of the sample cast ausferrite nodular iron with 0.4mass% Cr is the least. The wear loss began to increase while the Cr content is 0.6mass%. The wear loss of annealed ductile irons at different annealing temperatures was higher than that of as-cast samples. During the abrasive wear, the shear stress transformed austenite to martensite, and the hardness of specimens increased and the wear resistance of as-cast duc-tile cast iron was improved.

  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. 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%.

  20. Modeling wear of cast Ti alloys.

    Science.gov (United States)

    Chan, Kwai S; Koike, Marie; Okabe, Toru

    2007-05-01

    The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

  1. Industrial vegetable oil by-products increase the ductility of polylactide

    Directory of Open Access Journals (Sweden)

    A. Ruellan

    2015-12-01

    Full Text Available The use of industrial by-products of the vegetable oil industry as ductility increasing additives of polylactide (PLA was investigated. Vegetable oil deodorization condensates were melt-blended by twin-screw extrusion up to a maximum inclusion quantity of 20 wt% without preliminary purification. Sample films were obtained by single screw cast extrusion. Compounded PLA films featured largely improved ductility in tensile testing with an elongation at break up to 180%. The glass transition temperature remained higher than room temperature. The native mixture of molecules, which composed the deodorization condensates, had superior performance compared to a synthetic mixture of main compounds. The investigation of the correlation between composition of the additives and the ductility of the PLA blends by Principal Component Analysis showed synergy in property improvement between fatty acids having a melting point below and beyond the room temperature. Furthermore, a compatibilizing effect of molecules present in the native mixture was evidenced. Oil deodorization condensates, which are a price competitive by-product of the vegetable oil industry, are therefore a very promising biobased and biodegradable additive for improving the ductility of PLA.

  2. Mechanisms for Ductile Rupture - FY16 ESC Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, Brad L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carroll, Jay D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noell, Phillip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bufford, Daniel Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Clark, Blythe G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hattar, Khalid Mikhiel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lim, Hojun [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    Ductile rupture in metals is generally a multi-step process of void nucleation, growth, and coalescence. Particle decohesion and particle fracture are generally invoked as the primary microstructural mechanisms for room-temperature void nucleation. However, because high-purity materials also fail by void nucleation and coalescence, other microstructural features must also act as sites for void nucleation. Early studies of void initiation in high-purity materials, which included post-mortem fracture surface characterization using scanning electron microscopy (SEM) and high-voltage electron microscopy (HVEM) and in-situ HVEM observations of fracture, established the presence of dislocation cell walls as void initiation sites in high-purity materials. Direct experimental evidence for this contention was obtained during in-situ HVEM tensile tests of Be single crystals. Voids between 0.2 and 1 μm long appeared suddenly along dislocation cell walls during tensile straining. However, subsequent attempts to replicate these results in other materials, particularly α -Fe single crystals, were unsuccessful because of the small size of the dislocation cells, and these remain the only published in-situ HVEM observations of void nucleation at dislocation cell walls in the absence of a growing macrocrack. Despite this challenge, other approaches to studying void nucleation in high-purity metals also indicate that dislocation cell walls are nucleation sites for voids.

  3. Casting materials

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhry, Anil R. (Xenia, OH); Dzugan, Robert (Cincinnati, OH); Harrington, Richard M. (Cincinnati, OH); Neece, Faurice D. (Lyndurst, OH); Singh, Nipendra P. (Pepper Pike, OH)

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  4. Evaluation of significant manufacturing parameters in lost foam casting of thin-wall Al-Si-Cu alloy using full factorial design of experiment%影响消失模铸造Al-Si-Cu合金薄壁铸件质量的显著性工艺参数

    Institute of Scientific and Technical Information of China (English)

    Hassan JAFARI; Mohd Hsbullah IDRIS; Amirreza SHAYGANPOUR

    2013-01-01

    通过控制消失模铸造工艺参数可以制备出无缺陷的形状复杂的铸件产品。对 Al−Si−Cu 合金消失模铸造进行研究,考察浇注温度、涂料黏度、振动时间、型砂粒径以及它们之间的交互作用对铸件表面质量、孔隙率和共晶硅间距的影响。采用两水平全因子实验设计方法考察影响铸件性能的显著性影响工艺参数。结果表明,浇注温度和振动时间对铸件共晶硅间距和孔隙率的影响最明显。在细型砂模和较高的浇注温度下,铸件的表面质量几乎保持稳定不变,而在粗型砂模下铸件的表面质量较低。涂料黏度对铸件性能没有显著影响。%Controlling process parameters of lost foam casting (LFC) enables this process to produce defect-free complex shape castings. An experimental investigation on lost foam casting of an Al−Si−Cu cast alloy was carried out. The effects of pouring temperature, slurry viscosity, vibration time and sand size on surface finish, shrinkage porosity and eutectic silicon spacing of thin-wall casting were investigated. A full two-level factorial design of experimental technique was used to identify the significant manufacturing factors affecting the properties of casting. Pouring temperature was found as the most significant factor affecting Al−Si−Cu lost foam casting quality. It was shown that flask vibration time interacted with pouring temperature influenced eutectic silicon spacing and porosity percentage significantly. The results also revealed that the surface quality of the samples cast in fine sand moulds at higher pouring temperatures was almost unchanged, while those cast in coarse sand moulds possessed lower surface qualities. Furthermore, variation in slurry viscosity showed no significant effect on the evaluated properties compared to other parameters.

  5. The UK Casting Industry

    Institute of Scientific and Technical Information of China (English)

    Jincheng Liu

    2006-01-01

    The casting production in the UK in 2004 is presented and analysed. The UK casting industry has played an important role in world casting and manufacturing production. However recent years the rapid development of some developing countries has been shifting the casting production from the western industrialized countries including the UK. The UK casting industry and associated research and technology organizations, universities have been working together very hard to face the serious competition to make the UK casting industry have a sustainable future. The UK casting industry remains strong and plays an important role in world casting and manufacturing production.

  6. CA Investment Casting Process of Complex Castings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  7. Study on Microstructure and Properties of ADI Pneumatic Cylinder Casting%ADI风镐缸体铸件组织与力学性能研究

    Institute of Scientific and Technical Information of China (English)

    黄之德; 王生玖

    2012-01-01

    研制了一种含Cu、Ni合金成分的风镐缸体铸件,比较了其厚壁和薄壁处铸态和等温淬火态的组织和性能.结果表明:奥贝球铁风镐缸体铸态基体组织为珠光体,存在少量铁素体,石墨比较细小,大部分为球形,圆整度较好,球状石墨数量多;加入适量的合金,采用合理的热处理工艺,等温淬火后,厚壁和薄壁处的金相组织皆由贝氏体、奥氏体和少量碳化物组成,此时ADI(等温淬火球墨铸铁)具有较高的强度和塑性,能满足风镐缸体的使用要求,提高风镐的使用寿命,具有良好的经济性.%The microstructurc and mechanical properties of thick and thin wall of austempeted ductile iron cylinder casting with Cu, Ni alloy as-cast and isothermal quenching state were compared. The results show that the as-cast microstructure consists of pearlite, and a small amount of ferrite, graphite is small, most of graphite is spherical shape, good round degree, nodular graphite number is many, microstructure of isothermal quenching consists of bainite, austenitic and a small amount of carbide, austempered ductile iron with high strength and plasticity after isothermal quenching, can meet the requirements for the use of pneumatic cylinder.

  8. Microstructure and fracture of SiC-particulate-reinforced cast A356 aluminum alloy composites

    Science.gov (United States)

    Lee, Sunghak; Suh, Dongwoo; Kwon, Dongil

    1996-12-01

    A microstructural analysis of local microfracture of cast A356 Al-SiC p composites fabricated by permanent mold re-casting and squeeze-casting methods was made. Notch fracture toughness tests were conducted on these composites to identify critical fracture parameters using a stress-modified critical-strain criterion. The composite microstructure shows continuous networks of densely populated SiC and eutectic Si particles along the intercellular regions. Squeeze casting produces a more homogeneous structure and larger spacing of brittle particles and increases the tensile ductility and fracture toughness, while strength levels are almost identical to the re-casting case. The calculated values of the microstructurally characteristic distance l* for the re-cast and squeeze-cast composites are about 40 µm, which is comparable to the average sizes of the intercellular network. However, the reference critical strainbar \\varepsilon _0^* for squeeze casting is larger than that for re-casting, showing a trend to higher ductility and fracture toughness.

  9. The Comparison of Selected Methods of Cast Iron Spheroidization in Industrial Conditions

    Directory of Open Access Journals (Sweden)

    T. Válek

    2012-04-01

    Full Text Available Production of spheroidal graphite cast iron is today quite mastered technology. There are many methods achieving the nodular graphite morphology. Each of these methods have specific characteristics and requirements to technical support, properties and the type of applied modifier. Selection of the spheroidization method is dependent on foundry disposition, production character, economic balance, quality requirements, etc. In case of centrifugally casting the core, which fills body and neck of the roll, is created by ductile iron. Considering the sophisticated production of centrifugally cast rolls for hot rolling mills it is necessary to ensure a high reproducibility and reliability of ductile cast iron production quality in the bulk range of 9-18 t per tapping. These conditions are in the Roll Foundry in Vítkovicke Slevarny, spol. s r.o. provided and verified mastered overpour method and the newly injection of cored wire in the melt.

  10. Material specification and quality control program for ductile iron spent fuel casks

    Energy Technology Data Exchange (ETDEWEB)

    Rehmer, B.; Frenz, H.; Weidlich, S.; Kuehn, H.D.

    1995-12-31

    In the process of testing spent fuel casks, BAM is gaining a lot of relevant data regarding the quality level of Ductile Cast Iron (DCI). This paper discusses the basic parameters governing the material behavior of ferritic and ferritic-pearlitic DCI and reviews the development of cask quality over the last years. The effect of microstructure and sample size on the fracture toughness of DCI is discussed. The results of a test program show the prominent effect of pearlite content and graphite nodule structure in the mechanical and fracture toughness characteristics of DCI. This observation is important for quality assurance programs for shipping and storage casks of radioactive materials.

  11. 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.

  12. 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 ...

  13. 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.

  14. Solidification control in continuous casting of steel

    Indian Academy of Sciences (India)

    S Mazumdar; S K Ray

    2001-02-01

    An integrated understanding of heat transfer during solidification, friction/lubrication at solid-liquid interface, high temperature properties of the solidifying shell etc. is necessary to control the continuous casting process. The present paper elaborates upon the knowledge developed in the areas of initial shell formation, mode of mould oscillation, and lubrication mechanism. The effect of these issues on the caster productivity and the quality of the product has been discussed. The influence of steel chemistry on solidification dynamics, particularly with respect to mode of solidification and its consequence on strength and ductility of the solidifying shell, has been dealt with in detail. The application of these basic principles for casting of stainless steel slabs and processing to obtain good quality products have been covered.

  15. EVALUATION OF MACHINABILITY OF DUCTILE IRONS ALLOYED WITH Ni AND Cu IN TERMS OF CUTTING FORCES AND SURFACE QUALITY

    Directory of Open Access Journals (Sweden)

    Yücel AŞKUN

    2003-02-01

    Full Text Available Due to the enhanced strength, ductility and thoughness of Ductile Iron (DI when compared to the other types cast iron, its machinability is relatively poor. When a steel part is replaced with ductile iron, however, better machinability is considered to be the most important gain. This study presents the results of machining tests of ductile irons alloyed with Ni and Cu at various contents to determine the effect of their microstructure and mechanical properties on cutting forces and surface roughness. Six different specimen groups of ductile iron alloyed with various amounts of nickel and copper were subjected to machining tests and their machinabilities were investigated based on cutting forces and surface roughness criteria. The results were evaluated according to microstructure and mechanical properties of specimens determined before. In terms of both criterion, the best result obtained was specimen added 0.7 % Ni and 0.7 % Cu. When the specimens were evaluated according to their mechanical properties, the specimens alloyed 1 % Ni and 0.65 % Cu seemed promising.

  16. The ancient Chinese casting techniques

    OpenAIRE

    2011-01-01

    In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast ir...

  17. 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.)

  18. Manufacturing of Aluminum Composite Material Using Stir Casting Process

    Directory of Open Access Journals (Sweden)

    Muhammad Hayat Jokhio

    2011-01-01

    Full Text Available Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of \\"Al2O3\\" particles in 7xxx aluminum matrix. The 7xxx series aluminum matrix usually contains Cu-Zn-Mg. Therefore, the present research was conducted to investigate the effect of elemental metal such as Cu-Zn-Mg in aluminum matrix on mechanical properties of stir casting of aluminum composite materials reinforced with alpha \\"Al2O3\\" particles using simple foundry melting alloying and casting route. The age hardening treatments were also applied to study the aging response of the aluminum matrix on strength, ductility and hardness. The experimental results indicate that aluminum matrix cast composite can be manufactured via conventional foundry method giving very good responses to the strength and ductility up to 10% \\"Al2O3\\" particles reinforced in aluminum matrix.

  19. 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.

  20. Prediction of Ductile Fracture Surface Roughness Scaling

    DEFF Research Database (Denmark)

    Needleman, Alan; Tvergaard, Viggo; Bouchaud, Elisabeth

    2012-01-01

    Experimental observations have shown that the roughness of fracture surfaces exhibit certain characteristic scaling properties. Here, calculations are carried out to explore the extent to which a ductile damage/fracture constitutive relation can be used to model fracture surface roughness scaling....... The scaling properties of the predicted thickness average fracture surfaces are calculated and the results are discussed in light of experimental observations....

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Modelling of ductile failure in metal forming

    NARCIS (Netherlands)

    Wisselink, H.H.; Huetink, J.

    2009-01-01

    Damage and fracture are important criteria in the design of products and processes. Damage models can be used to predict ductile failure in metal forming processes. Nonlocal models avoid the mesh dependency problems of local damage models. A nonlocal damage model has been implemented in LSDYNA using

  6. Compaction of Ductile and Fragile Grains

    Science.gov (United States)

    Creissac, S.; Pouliquen, O.; Dalloz-Dubrujeaud, B.

    2009-06-01

    The compaction of powders into tablets is widely used in several industries (cosmetics, food, pharmaceutics…). In all these industries, the composition of the initial powder is complex, and the behaviour under compaction is not well known, also the mechanical behaviour of the tablets. The aim of this paper is to understand the behaviour (pressure vs density) of a simplified media made of fragile and ductile powders, varying the relative ratio of each powder. Some compaction experiments were carried out with glass beads (fragile) and Polyethylen Glycol powder (ductile). We observe two typical behaviours, depending on the relative volumic fraction of each component. A transition is pointed out, observing the evolution of the slope of the curve pressure/density. This transition is explained by geometrical considerations during compaction. A model is proposed, based on the assumption that the studied media can be compare to a diphasic material with a continuous phase (the ductile powder) and a discrete phase (the fragile powder). The result of this model is compare to the experimental results of compaction, and give a good prediction of the behaviour of the different mixing, knowing the behaviour of the ductile and the fragile phase separately. These results were also interpreted in terms of Heckel parameter which characterizes the ability of the powder to deform plastically under compaction. Some mechanical tests were also performed to compare the mechanical resitance of the obtained tablets.

  7. A new approach to develop complicated superalloy castings

    Institute of Scientific and Technical Information of China (English)

    WU Jian-tao; FENG Di; LI Jun-tao; KONG Sheng-guo; PEI Zhong-ye

    2006-01-01

    An integrative computer aided investment casting (CAIC) technology for making complicated superalloy castings was described. Key processes of CAIC were discussed including the choice of SLS (Selectively Laser Sinterihg)materials, sintering parameters, solidification simulation and gating and risering system optimization. Using CAIC process,many large-sized quality superalloy castings with complicated shape and thin wall have been produced successfully and economically in Central Iron & steel Research Institute (CISRI).

  8. A new approach to develop complicated superalloy castings

    Directory of Open Access Journals (Sweden)

    WU Jian-tao

    2006-05-01

    Full Text Available An integrative computer aided investment casting (CAIC technology for making complicated superalloy castings was described. Key processes of CAIC were discussed including the choice of SLS (Selectively Laser Sintering materials, sintering parameters, solidification simulation and gating and risering system optimization. Using CAIC process, many large-sized quality superalloy castings with complicated shape and thin wall have been produced successfully and economically in Central Iron & steel Research Institute (CISRI.

  9. 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.

  10. 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.

  11. 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.

  12. Seismic force modification factor for ductile structures

    Institute of Scientific and Technical Information of China (English)

    TONG Gen-shu; HUANG Jin-qiao

    2005-01-01

    The earthquake forces used in design codes of buildings should be theoretically determinable. This work examines the seismic force modification factor R based on elastic-plastic time-history earthquake analysis of SDOF systems, wherein the hysteresis models are elastic-perfectly-plastic (EPP), elastic-linearly-hardening (ELH), shear-slipped and bilinear-elastic. The latter two models are analysed for separating the effect of the ductility and the energy-dissipating capacity. Three-hundred eighty-eight earthquake records from different site conditions are used in analysis. The ductility is taken to be 2, 3, 4, 5 and 6, with the damping ratio being 0.02, 0.035 and 0.05 respectively. The post-yield stiffness ratios 0.0, 0.1 and 0.2 are used in the analysis. The R spectra are standardized by the characteristic period of the earthquake records, which leads to a much smaller scatter in averaged numerical results. It was found that the most important factor determining R is the ductility. R increases more than linearly with ductility. The energy-dissipating capacity, damping and the post-yield stiffness are the less important factors. The energy dissipating capacity is important only for structures with short period and moderate period (0.3≤T/Tg<5.0). For EPP and ELH models, R for 0.05 damping is 10% to 15% smaller than for 0.02 damping. For EPP and ELH models, greater post-yield stiffness leads to greater R, but the influence of post-yield stiffness is obvious only when the post-yield stiffness is less than 10% of the initial stiffness. By means of statistical regression analysis the relation of the seismic force modification factor R with the natural period of the system and ductility for EPP and ELH models were established for each site and soil condition.

  13. 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.

  14. 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.

  15. Diffusion of C and Cr During Creation of Surface Layer on Cast Steel Casting

    Directory of Open Access Journals (Sweden)

    Szajnar J.

    2014-10-01

    Full Text Available In paper a method of improvement in utility properties of unalloyed cast steel casting in result of diffusion of C and Cr in process of creation of surface layer is presented. The aim of paper was determination of diffusion range of basic elements of alloyed surface layer. Moreover a quantitative analysis of carbides phase strengthens alloyed surface layer of casting was carried out. The results of studies shown that important factors of surface layer creation are maximal temperature Tmax on granular insert – cast steel boundary dependent of pouring temperature, granularity Zw of Fe-Cr-C alloy insert and thickness of casting wall gśo. On the basis of obtained results was affirmed that with increase of thickness of casting wall increases range of diffusion in solid state in Fe-Cr-C grains and in liquid state. Moreover the range of Tmax = 13001500oC favours creation of the proper alloyed surface layers on cast steel.

  16. 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.

  17. 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.

  18. Analyses of cavitation instabilities in ductile metals

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    , and also tests for a thin ductile metal layer bonding two ceramic blocks have indicated rapid void growth. Analyses for these material configurations are discussed here. When the void radius is very small, a nonlocal plasticity model is needed to account for observed size-effects, and recent analyses...... analyzed for a material containing a periodic distribution of spherical voids with two different void sizes, where the stress fields around larger voids may accelerate the growth of smaller voids. Another approach has been an analysis of a unit cell model in which a central cavity is discretely represented......, while the surrounding voids are represented by a porous ductile material model in terms of a field quantity that specifies the variation of the void volume fraction in the surrounding metal....

  19. The austempering study of alloyed ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. A review of macroscopic ductile failure criteria.

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo; Reedlunn, Benjamin

    2013-09-01

    The objective of this work was to describe several of the ductile failure criteria com- monly used to solve practical problems. The following failure models were considered: equivalent plastic strain, equivalent plastic strain in tension, maximum shear, Mohr- Coulomb, Wellman's tearing parameter, Johnson-Cook and BCJ MEM. The document presents the main characteristics of each failure model as well as sample failure predic- tions for simple proportional loading stress histories in three dimensions and in plane stress. Plasticity calculations prior to failure were conducted with a simple, linear hardening, J2 plasticity model. The resulting failure envelopes were plotted in prin- cipal stress space and plastic strain space, where the dependence on stress triaxiality and Lode angle are clearly visible. This information may help analysts select a ductile fracture model for a practical problem and help interpret analysis results.

  1. Ductile fracture of metals under triaxial states of stress

    Science.gov (United States)

    Schrems, Karol Krumrey

    Silver interlayers between maraging steel base metal were examined to evaluate mechanisms leading to ductile failure in constrained thin metals. The constraint of the maraging steel base metal during uniaxial testing of constrained thin silver results in a large hydrostatic tension component, a small von Mises effective stress, and negligible far-field plasticity. The failure theory proposed by Rice and Tracey predicts uniform cavity wall expansion as a result of high triaxiality, in which an increase in plastic strain drives an increase in cavity size. The Rice and Tracey theory predicts significantly greater plastic strain than is experimentally observed. The theory developed by Huang, Hutchinson, and Tvergaard states that a cavitation limit exists at which a cavity continues to grow without an increase in elastic or plastic strain. This occurs when the energy stored in the elastic region is sufficient to drive continued cavity expansion. Inherent in both theories is the assumption of a single cavity in an infinite solid, which implies non-interacting cavities. Modifications have been developed to allow for multiple cavities, but assume pre-existing cavities. By examining silver interlayers previously loaded to various times at a fraction of the tensile strength where time-dependent failure is observed, it was found that some cavities were initially present in the as-bonded samples. Some of the initial cavities were spaced close enough to suggest localized interacting stress fields. This indicates that a failure model should be able to accommodate cavity spacing. The results suggest that cavities are continuously nucleating (from at least the 20 nanometers detectability limit) and grow, sometimes to over 500 nm in diameter. This thesis evaluates the number, size, shape and spacing of cavities in the silver interlayers and uses these results to evaluate ductile failure theories for metals subjected to high triaxial states of stress such as in constrained

  2. 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).

  3. Fiber laser cladding of nickel-based alloy on cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Arias-González, F., E-mail: felipeag@uvigo.es [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Val, J. del [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J. [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain)

    2016-06-30

    Highlights: • Fiber laser cladding of Ni-based alloy on cast iron was experimentally studied. • Two different types of cast iron have been analyzed: gray and ductile cast iron. • Suitable processing parameters to generate a Ni-based coating were determined. • Dilution is higher in gray cast iron samples than in ductile cast iron. • Ni-based coating presents higher hardness than cast iron but similar Young's modulus. - Abstract: Gray cast iron is a ferrous alloy characterized by a carbon-rich phase in form of lamellar graphite in an iron matrix while ductile cast iron presents a carbon-rich phase in form of spheroidal graphite. Graphite presents a higher laser beam absorption than iron matrix and its morphology has also a strong influence on thermal conductivity of the material. The laser cladding process of cast iron is complicated by its heterogeneous microstructure which generates non-homogeneous thermal fields. In this research work, a comparison between different types of cast iron substrates (with different graphite morphology) has been carried out to analyze its impact on the process results. A fiber laser was used to generate a NiCrBSi coating over flat substrates of gray cast iron (EN-GJL-250) and nodular cast iron (EN-GJS-400-15). The relationship between processing parameters (laser irradiance and scanning speed) and geometry of a single laser track was examined. Moreover, microstructure and composition were studied by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD). The hardness and elastic modulus were analyzed by means of micro- and nanoindentation. A hardfacing coating was generated by fiber laser cladding. Suitable processing parameters to generate the Ni-based alloy coating were determined. For the same processing parameters, gray cast iron samples present higher dilution than cast iron samples. The elastic modulus is similar for the coating and the substrate, while the Ni

  4. 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.

  5. Ductility of a 60-Story Shearwall Frame-Belt Truss (Virtual Outrigger Building

    Directory of Open Access Journals (Sweden)

    Pudjisuryadi P.

    2012-01-01

    Full Text Available Researches have been conducted to study Shearwall-frame combined with belt truss as structural system (SFBT, in which the post-elastic behavior and ductility of this structural system are explored. A 60-story SFBT building, with a ductility set equal to 3.75 (value for fully ductile cantilever wall is considered. The Elastic Response Spectrum used for design is taken from Zone 2 of Indonesian Seismic Map. Capacity design method according to Indonesian Concrete Code is employed. The seismic performance is analyzed using static non-linear push-over analysis and dynamic non-linear time-history analysis. Spectrum consistent ground motions of the May 18, 1940 El-Centro earthquake N-S components scaled to maximum accelerations of various return periods (50, 200, and 500 years are used for analysis. The results of this study show that plastic hinges mainly developed in beams above the truss, columns below the truss, and bottom levels of the wall. The building shows no indication of structural instability.

  6. Size effect on brittle and ductile fracture of two-dimensional interlinked carbon nanotube network

    Science.gov (United States)

    Jing, Yuhang; Aluru, N. R.

    2017-09-01

    The mechanical properties of two-dimensional (2D) interlinked carbon nanotube (CNT) network are investigated using ab initio calculation and molecular dynamics simulations (MD) with Reaxff force field. The simulation results show that bulk 2D interlinked CNT network has good mechanical properties along the axial direction which can be comparable to that of single-walled CNT and graphene, but has better ductility along the radial direction than single-walled CNT and graphene. In addition, the mechanical properties of 2D interlinked CNT network ribbon along the radial direction depend strongly on the size of the ribbon. The Young's modulus and Poisson's ratio decrease as the size increases while the fracture strain increases with the size increasing. By analyzing the atomic structural (both bond length and atomic von Mises stress) evolution of the ribbons, the mechanism of a brittle-to-ductile transition is revealed. The exploration of the mechanical properties of the 2D interlinked CNT network paves the way for application of the relevant devices that can benefit from the high Young's modulus, high tensile strength, and good ductility.

  7. Homogenization-based continuum plasticity-damage model for ductile failure of materials containing heterogeneities

    Science.gov (United States)

    Ghosh, Somnath; Bai, Jie; Paquet, Daniel

    2009-07-01

    This paper develops an accurate and computationally efficient homogenization-based continuum plasticity-damage (HCPD) model for macroscopic analysis of ductile failure in porous ductile materials containing brittle inclusions. Example of these materials are cast alloys such as aluminum and metal matrix composites. The overall framework of the HCPD model follows the structure of the anisotropic Gurson-Tvergaard-Needleman (GTN) type elasto-plasticity model for porous ductile materials. The HCPD model is assumed to be orthotropic in an evolving material principal coordinate system throughout the deformation history. The GTN model parameters are calibrated from homogenization of evolving variables in representative volume elements (RVE) of the microstructure containing inclusions and voids. Micromechanical analyses for this purpose are conducted by the locally enriched Voronoi cell finite element model (LE-VCFEM) [Hu, C., Ghosh, S., 2008. Locally enhanced Voronoi cell finite element model (LE-VCFEM) for simulating evolving fracture in ductile microstructures containing inclusions. Int. J. Numer. Methods Eng. 76(12), 1955-1992]. The model also introduces a novel void nucleation criterion from micromechanical damage evolution due to combined inclusion and matrix cracking. The paper discusses methods for estimating RVE length scales in microstructures with non-uniform dispersions, as well as macroscopic characteristic length scales for non-local constitutive models. Comparison of results from the anisotropic HCPD model with homogenized micromechanics shows excellent agreement. The HCPD model has a huge efficiency advantage over micromechanics models. Hence, it is a very effective tool in predicting macroscopic damage in structures with direct reference to microstructural composition.

  8. 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.

  9. Mechanical Characteristic Analysis of Post-construction Condition of Integral Cast-type Prestressed Anchor Cable Sheet Pile Wall%整体现浇式预应力锚索桩板墙工后工况力学特征分析

    Institute of Scientific and Technical Information of China (English)

    周登文; 王荣金; 岳辉

    2013-01-01

      将整体现浇式预应力锚索桩板墙运用在混凝土连续浇筑施工中,虽然可以缩短工期,减少成本投入,但其设计计算方法还不成熟。通过对云南某山区高速公路上整体现浇预应力锚索桩板墙结构形式实体工程系统的型试验研究,实测锚索桩板墙在不同工况下的内力及填土土压力,以此为基础分析了该支挡结构在各工况下的力学特征,为设计计算方法的改进提供参考据。本文选取工后工况下桩板墙的力学特征分析进行阐述。%Integral cast-type prestressed anchor cable sheet pile wall used in the construction of continuous cast concrete shortens the duration and reduces capital costs, but its design calculation method is not yet ripe. By the research on prototype test of whole in-situ prestressed anchor cable sheet pile wall structure entities of a mountain highway in Yunnan province, measures the internal force and fill stress of anchor cable sheet pile wall in different conditions, based on this, analyzes the mechanical characteristics of retaining structures in all of the following conditions, providing reference for improvement of design calculation method. The paper presents the mechanical characteristics of pile-sheet retaining wall under elaboration.

  10. Welding and mechanical properties of cast FAPY (Fe-16 at. % Al-based) alloy slabs

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J.; Howell, C.R.

    1995-08-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10, and iron = 83.71. The cast ingots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot- worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  11. LLNL casting technology

    Science.gov (United States)

    Shapiro, A. B.; Comfort, W. J., III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US competiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  12. 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.

  13. Repair welding of cast iron coated electrodes

    Science.gov (United States)

    Żuk, M.; Górka, J.; Dojka, R.; Czupryński, A.

    2017-08-01

    Welding cast iron is a complex production procedure. Repair welding was used to repair damaged or poorly made castings. This is due to a tendency to cracking of the material during welding as well as after it. Welding cast iron can be carried out on hot or on cold. Hot welding requires high heat material and the use of welding material in the form of cast iron. In the case of cold welding, it is possible to use different materials. Mostly used filler metals are nickel and copper based. The work shows the course of research concerning repairmen of ductile iron with arc welding method. For the reparation process four types of ESAB company coated electrodes dedicated for cast iron were used with diameter 3.2 and 4 mm: ES 18-8-6B (4mm), EB 150 (4mm), OK NiCl, EŻM. In the cast iron examined during the testing grooves were made using plasma methods, in order to simulate the removed casting flaws. Then the welding process with coated electrodes was executed. The process utilized low welding current row of 100A, so there would only be a small amount of heat delivered to the heat affected zone (HAZ). Short stitches were made, after welding it was hammered, in order to remove stresses. After the repair welding the part of studies commenced which purpose was finding surface defects using visual testing (VT) and penetration testing (PT). In the second part, a series of macro and microscopic studies were executed witch the purpose of disclosuring the structure. Then the hardness tests for welds cross sections were performed. An important aspect of welding cast iron is the colour of the padding weld after welding, more precisely the difference between the base material and padding weld, the use of different materials extra gives the extra ability to select the best variant. The research of four types of coated electrode was executed, based on the demands the best option in terms of aesthetic, strength and hardness.

  14. Effect of Wall Thickness on Microstructure and Property of ZA52 Magnesium Alloy by Semi-Solid Squeezing Casting%壁厚对ZA52镁合金半固态挤压件组织性能的影响

    Institute of Scientific and Technical Information of China (English)

    阎峰云; 邵敬涛; 樊志斌; 黄晓锋; 陈体军; 马颖

    2012-01-01

    采用优化的试验参数,在四柱压力机上对ZA52镁合金进行半固态触变挤压试验,制备出阶梯试样.对其不同壁厚处的组织、性能进行了分析,并与金属型浇注、半固态压铸做了对比.结果表明:挤压件中出现液固分离现象;随着壁厚的减小,其固相颗粒组织由近似圆形过渡为梭形,有些颗粒甚至压合在一起;其抗拉强度由208.4MPa增加到270.1MPa、伸长率由7.10%增加到17.71%,最小壁厚处综合力学性能最好,且明显优于金属型浇铸及半固态压铸.%The three-step parts of ZA52 magnesium alloy have been obtained by using semi-solid squeezing casting with optimum parameters on the four-column hydraulic press with metal mold The microstructure and mechanical properties of the different zones have been contrasted and analyzed, which are different from other casting processes such as permanent mold casting and semi-solid die-casting. The results show that the liquid-solid separation exists in the squeezing parts; the microstructure changes from round to fusiform, and even some spheres press together with the decrease of thickness; the tensile strength increases from 208.4 MPa to 270.1 MPa. and the elongation increases from 7.10% to 17.71%. The comprehensive mechanical properties of the thinnest wall thickness are better than others and those of permanent mold casting and semi-solid die-casting.

  15. Response Modification Factor of Coupled Steel Shear Walls

    Directory of Open Access Journals (Sweden)

    gholamreza abdollahzadeh

    2013-06-01

    Full Text Available The present research is concerned with the determination of ductility, over-strength and response modification factors of coupled steel shear wall frames. Three structural models with various numbers of stories, bay width and coupling beam height were analyzed using static pushover and incremental nonlinear dynamic analyses. The ductility, over-strength and response modification factors for the three models are determined. Tentative values of 11.1, 11.6 and 10.6 are suggested for the response modification factor of coupled steel shear wall frames with deep and medium depth coupling beams, and uncoupled steel shear wall frames, respectively in the allowable stress design method.

  16. Bacterial community radial-spatial distribution in biofilms along pipe wall in chlorinated drinking water distribution system of East China.

    Science.gov (United States)

    Liu, Jingqing; Ren, Hongxing; Ye, Xianbei; Wang, Wei; Liu, Yan; Lou, Liping; Cheng, Dongqing; He, Xiaofang; Zhou, Xiaoyan; Qiu, Shangde; Fu, Liusong; Hu, Baolan

    2017-01-01

    Biofilms in the pipe wall may lead to water quality deterioration and biological instability in drinking water distribution systems (DWDSs). In this study, bacterial community radial-spatial distribution in biofilms along the pipe wall in a chlorinated DWDS of East China was investigated. Three pipes of large diameter (300, 600, and 600 mm) were sampled in this DWDS, including a ductile cast iron pipe (DCIP) with pipe age of 11 years and two gray cast iron pipes (GCIP) with pipe ages of 17 and 19 years, and biofilms in the upper, middle, and lower parts of each pipe wall were collected. Real-time quantitative polymerase chain reaction (qPCR) and culture-based method were used to quantify bacteria. 454 pyrosequencing was used for bacterial community analysis. The results showed that the biofilm density and total solid (TS) and volatile solid (VS) contents increased gradually from the top to the bottom along the pipe wall. Microorganisms were concentrated in the upper and lower parts of the pipe wall, together accounting for more than 80 % of the total biomass in the biofilms. The bacterial communities in biofilms were significantly different in different areas of the pipe wall and had no strong interaction. Compared with the upper and lower parts of the pipe wall, the bacterial community in the middle of the pipe wall was distributed evenly and had the highest diversity. The 16S rRNA genes of various possible pathogens, including Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Salmonella enterica, were detected in the biofilms, and the abundances of these possible pathogens were highest in the middle of the pipe wall among three areas. The detachment of the biofilms is the main reason for the deterioration of the water quality in DWDSs. The results of this study suggest that the biofilms in the middle of the pipe wall have highly potential risk for drinking water safety, which provides new ideas for the study of the microbial ecology in

  17. Design optimization of gating and feeding system through simulation technique for sand casting of wear plate

    Directory of Open Access Journals (Sweden)

    Sachin L. Nimbulkar

    2016-09-01

    Full Text Available Casting is a manufacturing process to make complex shapes of metal materials; during mass production, we may experience many defects, such as gas porosity, pin holes, blow holes, shrinkages and incomplete filling that may occur in sand casting. Porosity is one of the defects most frequently encountered in ductile iron casting. Porosity impacts cost by scrap loss and limits the use of cast parts in critical high strength applications. The amount of porosity is closely related to the parameter of sand casting process. The gating/riser system design plays a very important role for improving casting quality. Many researchers reported that 90% of the defects in casting are obtained only because of improper design of gating and feeding system. The main objectives were to study the existing design of gating and feeding system, to optimize the gating and feeding system using Auto-CAST X1 casting simulation software, to prepare the sand mold and cast the part, to compare the simulated result and experimental results, to reduce rejection rate and to enable the company to again start the production.

  18. Effects of casting conditions and deformation processing on A356 aluminum and A356-20 vol. pct SiC composites

    Science.gov (United States)

    Rozak, G. A.; Lewandowski, J. J.; Wallace, J. F.; Altmisoglu, A.

    1992-01-01

    The effects of casting conditions and deformation processing on the mechanical properties of unreinforced A356 aluminum and A356-20 vol pct SiC composite were investigated by tensile properties in these compounds fabricated by either sand casting or squeeze casting techniques followed by hot working to 33, 50, 90, and 95 percent reductions. The evolution of the microstructure and values of tensile properties were evaluated for the cast materials in each of the hot worked conditions. It was found that, while the deformation processing of the sand-cast composite resulted in banding of the Al and SiC particles within the microstructure, such features were not observed in the squeeze-cast microstructure. The tensile strengths of the squeeze cast materials was found to be higher than those of the sand cast materials, for both the unreinforced and composite samples, while increased amounts of deformation were found to improve the ductility of the composite.

  19. Age Strengthening of Gray Cast Iron Phase III

    Energy Technology Data Exchange (ETDEWEB)

    Von L. Richards; Wayne Nicola

    2003-06-26

    The primary objective of this research is to identify the age strengthening mechanism in gray and ductile cast iron, and to quantify the parameters that control it. It is also to contribute to a new predictive model for gray and ductile iron strength and hardness. This work shows that age strengthening occurs on a sigmoidal-logarithmic scale in gray and ductile cast irons, to a statistically significant extent. This is similar to Avrami-Johnson-Mehl kinetics for phase transformations in metals. It occurs in both cupola-melted iron and induction melted iron. However, it does not happen in all compositions. We have developed some understanding of the process. Data suggests that nitrogen and nitride-forming trace elements have a significant role in the process, but that is yet not fully characterized. Also, the time dependence of the bulk hardness and strength increase, the nano-scale precipitation evidence from neutron scattering, differential scanning calorimetry results and matrix micro-hardness increase in ferrite all indicate that age strengthening occurs by a precipitation or pre-precipitate cluster formation mechanism.

  20. Flexural strength and ductility of reinforced concrete beams

    OpenAIRE

    Kwan, AKH; Ho, JCM; Pam, HJ

    2002-01-01

    In the design of reinforced concrete beams, especially those made of high-strength concrete and those in earthquake-resistant structures, both the flexural strength and ductility need to be considered. From the numerical results obtained in a previous study on the post-peak behaviour and flexural ductility of reinforced concrete beams, the interrelation between the flexural strength and the flexural ductility that could be simultaneously achieved was evaluated and plotted in the form of chart...

  1. 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.)

  2. 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...

  3. 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.

  4. Ductile alloys for sealing modular component interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Marra, John J.; Wessell, Brian J.; James, Allister W.; Marsh, Jan H.; Gear, Paul J.

    2017-08-08

    A vane assembly (10) having: an airfoil (12) and a shroud (14) held together without metallurgical bonding there between; a channel (22) disposed circumferentially about the airfoil (12), between the airfoil (12) and the shroud (14); and a seal (20) disposed in the channel (22), wherein during operation of a turbine engine having the vane assembly (10) the seal (20) has a sufficient ductility such that a force generated on the seal (20) resulting from relative movement of the airfoil (12) and the shroud (14) is sufficient to plastically deform the seal (20).

  5. Ductile Damage Evolution and Strain Path Dependency

    Science.gov (United States)

    Tasan, C. C.; Hoefnagels, J. M. P.; Peerlings, R. H. J.; Geers, M. G. D.; ten Horn, C. H. L. J.; Vegter, H.

    2007-04-01

    Forming limit diagrams are commonly used in sheet metal industry to define the safe forming regions. These diagrams are built to define the necking strains of sheet metals. However, with the rise in the popularity of advance high strength steels, ductile fracture through damage evolution has also emerged as an important parameter in the determination of limit strains. In this work, damage evolution in two different steels used in the automotive industry is examined to observe the relationship between damage evolution and the strain path that is followed during the forming operation.

  6. Microstructure and Mechanical Properties of AA2195 DC Cast Ingot Plates

    Science.gov (United States)

    Elgallad, E. M.; Hekmat-Ardakan, A.; Ajersch, F.; Chen, X.-G.

    DC cast ingot plates are especially suitable for large mold manufacturing in the plastic and automotive industries. The microstructures and mechanical properties of AA2195 DC cast ingot plates in the as-cast and heat-treated conditions were studied. Aging treatments were carried out at 125 and 150°C for 12 and 24 h. A microstructural analysis was conducted using optical and scanning electron microscopies as well as a differential scanning calorimetry. The results show a significant increase in yield and tensile strengths after aging at 150°C. It is suggested that the strengthening of AA2195 cast plates is largely determined by the proportion of both θ'-Al2Cu and T1-Al2CuLi precipitations. By adopting an appropriate heat treatment, AA2195 cast ingot plates can provide a range of satisfactory combinations of strength and ductility which fulfill the design requirements of large mold applications.

  7. Modelling of Filling, Microstructure Formation, Local Mechanical Properties and Stress – Strain Development in High-Pressure Die Cast Aluminium Castings

    DEFF Research Database (Denmark)

    Kotas, Petr; Hattel, Jesper Henri; Thorborg, Jesper

    2009-01-01

    inherently affects the component’s properties depending on design, metallurgy and casting technique. The wall thickness influences the coarseness of the microstructure and the material will have properties depending on the local metallurgical and thermal histories. This is independent on the material, i.......e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it complex to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... product has constant material properties throughout the entire casting. Thus, if the microstructure is determined or predicted at a given point, it gives the possibility to calculate the local material behavior more realistically. In the present work, a test case of a complex high-pressure die cast part...

  8. Construction-friendly ductile shear joints for precast concrete panels

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Fischer, Gregor

    2015-01-01

    The scope of this paper is the shear capacity of in-situ cast joints between precast concrete panels. Current practice with vertical lowering of the wall panels experiences difficulties in the assembly phase, since the traditional U-bar connection requires an overlap in a horizontal plane to allow....... The solution is tested in a push-off experimental setup and the influence of important geometric parameters of the keyed shear joint is investigated. The first peak load carrying capacity is assessed using plasticity models, and the failure modes are identified by the use of digital image correlation....... The upper bound models produce satisfactory results capturing the experimental tendencies and predicting the mode of shear failure in the shear keys....

  9. Shrinkages in heavy-sized cast components of nodular cast iron – NDT and fatigue

    Directory of Open Access Journals (Sweden)

    Bleicher Christoph

    2014-06-01

    Full Text Available Material defects like shrinkages, dross, pores and chunky graphite are likely to occur in thick-walled castings and are a challenge for the foundries and their customers. These defects are mostly detected with handheld ultrasonic testing (UT or X-ray analysis. Within a research project done at the Fraunhofer Institute for Structural Durability and System Reliability LBF, the fatigue of Dross, shrinkages and chunky graphite in thick-walled cast material GGG-40 was estimated based on X-ray and fatigue tests on bending specimens. High fatigue reductions were received for the different material imperfections. Based on these impressions a further research project was executed at the Fraunhofer LBF to get an estimation of the informational value of UT in relation to fatigue of shrinkages in thick-walled castings of the material EN-GJS-400-18U-LT, EN-GJS-450-18 and EN-GJS-700-2. With the help of X-ray analysis and the UT technique Sampling Phased Array (SPA information about geometry and density were derived for a numerical analysis of shrinkages in thick-walled castings concerning fatigue. The following text summarizes the fatigue results achieved in the two research projects with the help of the X-ray and UT analysis.

  10. 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.

  11. Mathematical Modeling of Surface Roughness of Castings Produced Using ZCast Direct Metal Casting

    Science.gov (United States)

    Chhabra, M.; Singh, R.

    2015-04-01

    Aim of this investigation is to develop a mathematical model for predicting surface roughness of castings produced using ZCast process by employing Buckingham's π-theorem. A relationship has been proposed between surface roughness of castings and shell wall thickness of the shell moulds fabricated using 3D printer. Based on model, experiments were performed to obtain the surface roughness of aluminium, brass and copper castings produced using ZCast process based on 3D printing technique. Based on experimental data, three best fitted third-degree polynomial equations have been established for predicting the surface roughness of castings. The predicted surface roughness values were then calculated using established best fitted equations. An error analysis was performed to compare the experimental and predicted data. The average prediction errors obtained for aluminium, brass and copper castings are 10.6, 2.43 and 3.12 % respectively. The obtained average surface roughness (experimental and predicted) values of castings produced are acceptable with the sand cast surface roughness values range (6.25-25 µm).

  12. Squeeze casting of aluminum alloy A380: Microstructure and tensile behavior

    Directory of Open Access Journals (Sweden)

    Li Fang

    2015-09-01

    Full Text Available A380 alloy with a relatively thick cross-section of 25 mm was squeeze cast using a hydraulic press with an applied pressure of 90 MPa. Microstructure and tensile properties of the squeeze cast A380 were characterized and evaluated in comparison with the die cast counterpart. Results show that the squeeze cast A380 possesses a porosity level much lower than the die cast alloy, which is disclosed by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength (UTS: 215.9 MPa and elongation (Ef: 5.4%, for the squeeze cast samples over those of the conventional high-pressure die cast part (UTS: 173.7 MPa, Ef: 1.0%. The analysis of tensile behavior shows that the squeeze cast A380 exhibits a high tensile toughness (8.5 MJ·m-3 and resilience (179.3 kJ·m-3 compared with the die cast alloy (toughness: 1.4 MJ·m-3, resilience: 140.6 kJ·m-3, despite that, during the onset of plastic deformation, the strain-hardening rate of the die cast specimen is higher than that of the squeeze cast specimens. The microstructure analyzed by the scanning electron microscopy (SEM shows that both the squeeze and die cast specimens contain the primary α-Al, Al2Cu, Al5FeSi phase and the eutectic Si phase. But, the Al2Cu phase present in the squeeze cast alloy is relatively large in size and quantity. The SEM fractography evidently reveals the ductile fracture features of the squeeze cast A380 alloy.

  13. 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.)

  14. Ductile Fracture Initiation of Anisotropic Metal Sheets

    Science.gov (United States)

    Dong, Liang; Li, Shuhui; He, Ji

    2017-07-01

    The objective of this research is to investigate the influence of material plastic anisotropy on ductile fracture in the strain space under the assumption of plane stress state for sheet metals. For convenient application, a simple expression is formulated by the method of total strain theory under the assumption of proportional loading. The Hill 1948 quadratic anisotropic yield model and isotropic hardening flow rule are adopted to describe the plastic response of the material. The Mohr-Coulomb model is revisited to describe the ductile fracture in the stress space. Besides, the fracture locus for DP590 in different loading directions is obtained by experiments. Four different types of tensile test specimens, including classical dog bone, flat with cutouts, flat with center holes and pure shear, are performed to fracture. All these specimens are prepared with their longitudinal axis inclined with the angle of 0°, 45°, and 90° to the rolling direction, respectively. A 3D digital image correlation system is used in this study to measure the anisotropy parameter r 0, r 45, r 90 and the equivalent strains to fracture for all the tests. The results show that the material plastic anisotropy has a remarkable influence on the fracture locus in the strain space and can be predicted accurately by the simple expression proposed in this study.

  15. Glovebox Advanced Casting System Casting Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses. Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.

  16. High integrity automotive castings

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)

    2007-07-01

    This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

  17. Improving Metal Casting Process

    Science.gov (United States)

    1998-01-01

    Don Sirois, an Auburn University research associate, and Bruce Strom, a mechanical engineering Co-Op Student, are evaluating the dimensional characteristics of an aluminum automobile engine casting. More accurate metal casting processes may reduce the weight of some cast metal products used in automobiles, such as engines. Research in low gravity has taken an important first step toward making metal products used in homes, automobiles, and aircraft less expensive, safer, and more durable. Auburn University and industry are partnering with NASA to develop one of the first accurate computer model predictions of molten metals and molding materials used in a manufacturing process called casting. Ford Motor Company's casting plant in Cleveland, Ohio is using NASA-sponsored computer modeling information to improve the casting process of automobile and light-truck engine blocks.

  18. Energy Saving Melting and Revert Reduction Technology: Aging of Graphitic Cast Irons and Machinability

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Von L. [Advanced Technology Inst., Virginia Beach, VA (United States)

    2012-09-19

    The objective of this task was to determine whether ductile iron and compacted graphite iron exhibit age strengthening to a statistically significant extent. Further, this effort identified the mechanism by which gray iron age strengthens and the mechanism by which age-strengthening improves the machinability of gray cast iron. These results were then used to determine whether age strengthening improves the machinability of ductile iron and compacted graphite iron alloys in order to develop a predictive model of alloy factor effects on age strengthening. The results of this work will lead to reduced section sizes, and corresponding weight and energy savings. Improved machinability will reduce scrap and enhance casting marketability. Technical Conclusions: Age strengthening was demonstrated to occur in gray iron ductile iron and compacted graphite iron. Machinability was demonstrated to be improved by age strengthening when free ferrite was present in the microstructure, but not in a fully pearlitic microstructure. Age strengthening only occurs when there is residual nitrogen in solid solution in the Ferrite, whether the ferrite is free ferrite or the ferrite lamellae within pearlite. Age strengthening can be accelerated by Mn at about 0.5% in excess of the Mn/S balance Estimated energy savings over ten years is 13.05 trillion BTU, based primarily on yield improvement and size reduction of castings for equivalent service. Also it is estimated that the heavy truck end use of lighter castings for equivalent service requirement will result in a diesel fuel energy savings of 131 trillion BTU over ten years.

  19. 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

  20. Performance Steel Castings

    Science.gov (United States)

    2012-09-30

    alloys , foundry, muzzle brake, supply center, tooling, sources Notice Distribution Statement A Format Information Report created in Microsoft Word...Development of Sand Properties 103 Advanced Modeling Dataset.. 105 High Strength Low Alloy (HSLA) Steels 107 Steel Casting and Engineering Support...University, University of Northern Iowa, Non- Ferrous Founders’ Society, QuesTek, buyCASTINGS.com, Spokane Industries, Nova Precision Casting, Waukesha

  1. Hot ductility of medium carbon steel with vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang-Hoon, E-mail: lee1626@kims.re.kr [Korea Institute of Materials Science, Changwon, Gyeongnam 642-831 (Korea, Republic of); Park, Jun-Young [Korea Institute of Materials Science, Changwon, Gyeongnam 642-831 (Korea, Republic of); Chung, JunHo; Park, Dae-Bum; Jang, Jin-Young; Huh, Sungyul; Ju Kim, Sung [R& D Center, Hyundai Steel Company, Dangjin, Chungnam 343-823 (Korea, Republic of); Kang, Jun-Yun; Moon, Joonoh; Lee, Tae-Ho [Korea Institute of Materials Science, Changwon, Gyeongnam 642-831 (Korea, Republic of)

    2016-01-10

    Hot ductility of medium carbon steel containing 0.52 wt% of carbon and 0.11 wt% of vanadium was investigated using a hot tensile test performed up to fracture. The hot ductility was evaluated by measuring the reduction of area of the fractured specimens, which were strained at a variety of test temperatures in a range of 600–1100 °C at a strain rate of 2×10{sup −3}/s. The hot ductility was excellent in a temperature range of 950–1100 °C, followed by a decrease of the hot ductility below 950 °C. The hot ductility continued to drop as the temperature was lowered to 600 °C. The loss of hot ductility in a temperature range of 800–950 °C, which is above the Ae{sub 3} temperature, was due to V(C,N) precipitation at austenite grain boundaries. The further decline of hot ductility between 700 °C and 750 °C resulted from the transformation of ferrite films decorating austenite grain boundaries. The hot ductility continued to decrease at 650 °C or less, owing to ferrite films and the pearlite matrix, which is harder than ferrite. The pearlite was transformed from austenite due to relatively high carbon content.

  2. Evolution of halictine castes

    Science.gov (United States)

    Knerer, Gerd

    1980-03-01

    Social halictine bees have female castes that range from species with no size differences to those with a discrete bimodality. Female caste differences are inversely correlated with the number of males produced in the first brood. It is proposed that the sexual dimorphism of solitary forms is being usurped by the female caste system of species in the process of turning social. Thus, caste differences and summer male suppression are greatest in the social species originating from solitary precursors with distinct sexual dimorphism, and are least in species evolving from solitary ancestors with a continuous sexual polymorphism.

  3. Enhancements in Magnesium Die Casting Impact Properties

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    % in AM50 to over 9% in AZ91, more of the intermetallic Mg17Al12 is formed in the microstructure. For instance, for 15 increase in the aluminum content from AM50 to AM60, the volume fraction of eutectic present in the microstructure increases by 35%! Eventually, the brittle Mg17Al12 compound forms an interconnected network that reduces ductility and impact resistance. The lower aluminum in AM50 and AM60 are therefore a desirable feature in applications that call for higher impact resistance. Further improvement in impact resistance depends on the processing condition of the casting. Sound castings without porosity and impurities will have better mechanical properties. Since magnesium oxidizes readily, good melting and metal transfer practices are essential. The liquid metal has to be protected from oxidation at all times and entrainment of oxide films in the casting needs to be prevented. In this regard, there is evidence that us of vacuum to evacuate air from the die casting cavity can improve the quality of the castings. Fast cooling rates, leading to smaller grain size are beneficial and promote superior mechanical properties. Micro-segregation and banding are two additional defect types often encountered in magnesium alloys, in particular in AZ91D. While difficult to eliminate, segregation can be minimized by careful thermal management of the dies and the shot sleeve. A major source of segregation is the premature solidification in the shot sleeve. The primary solid dendrites are carried into the casting and form a heterogeneous structure. Furthermore, during the shot, segregation banding can occur. The remedies for this kind of defects include a hotter shot sleeve, use of insulating coatings on the shot sleeve and a short lag time between pouring into the shot sleeve and the shot.

  4. SYSTEMATIC AND DYNAMIC PROPER-TIES OF CASTING HOT SPOT

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The variation of casting hot spot with proceeding of solidification and components of casting-mold system is studied by the technique of numerical simulation of solidification.The result shows that the thickest part of casting is not exactly the last part of solidification in the casting, while the last part of solidification is not exactly casting hot spot at the early stage of solidification.The location, size, shape and number of casting hot spot change with geomitric, physical and technological factors of the casting-mold system such as thickness of the casting secondary wall and with the passage of time in the course of the solidification.The former is known as the systematic property of hot spot and the latter, dynamic property.Only when the properties of hot spot are grasped completely and accurately, can it be fed more effectively.By doing so, not only sound castings can be obtained, but also riser efficiency can be improved.

  5. Thermodynamical Framework for Ductile Damage and Plasticity

    Science.gov (United States)

    César de Sá, José M. A.; Andrade, Filipe X. C.; Andrade Pires, Francisco M.

    2010-05-01

    Many models employed for the prediction of plastic deformation rely exclusively on elastoplastic theories, disregarding significant effects of internal degradation [1]. Constitutive models based on the Continuum Damage Mechanics theory provide more realistic predictions since damage is taken into account as an internal variable. In the present contribution, Lemaire's model for ductile damage [2] is questioned under the assumption of the principle of maximum inelastic dissipation [3]. The model is enhanced with a nonlocal formulation where the damage variable is spatially averaged by means of an integral operator [4]. Thermodynamical admissibility of the nonlocal model is checked by applying the global version of the Clausius-Duhem inequality [5]. Results from numerical analysis show that the constitutive model is insensitive to spatial discretization.

  6. Caste in Itself, Caste and Class, or Caste in Class

    OpenAIRE

    Ramkrishna Mukherjee

    2015-01-01

    After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1) the relation of people to land for production (and not for revenue receiving, household living, etc.), and (2) the caste system of India, viz. the jati strati?cation of society.

  7. Enhanced ductility in round tensile bars produced by cladding a ductile ring

    Science.gov (United States)

    Chen, X. X.; Wu, P. D.; Embury, J. D.; Huang, Y.

    2010-03-01

    The effect of cladding a ductile ring on necking and fracture in round bars under tension is studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that the cladding increases both the necking strain and the fracture strain. The effects of topological arrangement of cladding ring on necking and fracture are numerically investigated. It is indicated that while a topological arrangement of cladding has no noticeable effect on necking, it significantly influences the fracture strain. For a given volume fraction of cladding, the fracture strain could increase about 11% if the ductile ring is moved from the outmost to the innermost. It is also found that the subtle appearance of fracture surface due to cladding displays strong mesh sensitivity and may even be an artefact of the mesh.

  8. Role of multi-microalloying by rare earth elements in ductilization of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Yuanding Huang

    2014-03-01

    Full Text Available The present work investigates the influences of microalloying with rare earths on the mechanical properties of magnesium alloys. The amount of each rare earth element is controlled below 0.4 wt.% in order not to increase the cost of alloy largely. The synergic effects from the multi-microalloying with rare earths on the mechanical properties are explored. The obtained results show that the as-cast magnesium alloys multi-microalloying with rare earths possesses a quite high ductility with a tensile strain up to 25–30% at room temperature. Moreover, these alloys exhibit much better corrosion resistance than AZ31 alloy. The preliminary in situ neutron diffractions on the deformation of these alloys indicate that the multi-microalloying with rare earths seems to be beneficial for the activation of more slip systems. The deformation becomes more homogeneous and the resultant textures after deformation are weakened.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.)

  14. Effects of Eutectic Si Particles on Mechanical Properties and Fracture Toughness of Cast A356 Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyu Hong; Lee, Sung Hak [Pohang Univ. of Institute of Science and Technology, Pohang (Korea, Republic of); Kwon, Yong Nam [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-01-15

    The present study aims at investigating the effects of eutectic Si particles on mechanical properties and fracture toughness of three A356 aluminum alloys. These A356 alloys were fabricated by casting processes such as rheo-casting, squeeze-casting, and casting-forging, and their mechanical properties and fracture toughness were analyzed in relation with microfracture mechanism study. All the cast A356 alloys contained eutectic Si particles mainly segregated along solidification cells, and the distribution of Si particles was modified by squeeze-casting and casting-forging processes. Microfracture observation results showed that eutectic Si particles segregated along cells were cracked first, but that aluminum matrix played a role in blocking crack propagation. Tensile properties and fracture toughness of the squeeze cast and cast-forged alloys having homogeneous distribution of eutectic Si particles were superior to those of the rheo-cast alloy. In particular, the cast-forged alloy had excellent hardness, strength, ductility, and fracture toughness because of the matrix strengthening and homogeneous distribution of eutectic Si particles due to forging process.

  15. 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.

  16. 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.)

  17. 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.

  18. 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.

  19. 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. 

  20. Effects of boron addition and austempering time on microstructure, hardness and tensile properties of ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Guerra L, F.V. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Bedolla-Jacuinde, A., E-mail: abedollj@icloud.com [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Mejía, I. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Facultad de Ingeniería Mecánica UAEH, México (Mexico); Zuno, J. [Facultad de Ingeniería Mecánica UAEH, México (Mexico); Maldonado, C. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico)

    2015-11-11

    The present work analyzes the effect of boron addition to an Austempered Ductile Iron, in amounts from zero to 120 ppm. It has been found that boron has a strong effect on the equivalent carbon content, resulting in an increase on the precipitated graphite volume and a decrease in the dissolved carbon content in the matrix. This in turn, increases the ferrite volume fraction in the as-cast conditions from 0.24 in the base alloy to 0.78 for the iron with 120 ppm of boron. Furthermore, a decrease in the nodularity from 100% in the base alloy to 83% with 120 ppm of boron has been observed. During austempering, the transformation to ausferrite was faster and lower volumes of martensite and unstable austenite were detected when boron increased; this promoted lower hardness values, 239 HV for the base iron and 189 HV for the 120 ppm boron alloy. The increase in hardness and strength, typical for the start of bainite formation, were not observed in the boron added irons, but just in the base alloy. Under this basis, it is assumed that at least the addition of 60 ppm of boron extended the optimal processing window. The higher values of strength and ductility were obtained for the alloy with 60 ppm of boron; these results are discussed in terms of the graphitizing effect of boron in these irons and the reduced amount of carbon dissolved in austenite.

  1. DESIGN AND FABRICATION OF A CENTRIFUGAL CASTING MACHINE

    Directory of Open Access Journals (Sweden)

    Adedipe Oyewole

    2011-12-01

    Full Text Available The design and fabrication of a centrifugal casting machine was successfully carried out. The operation of the machine was based on the principle of centrifugal force. Suitable design theory, analysis and calculation were adopted carried out in the course of the work. The mold is bolted to the base plate which can rotate at moderatespeeds thereby forcing the molten metal against the inner walls of the mold. This machine could be used to cast small engineering components. The centrifugal force on the machine was determined to be 3207.3N, while the required power on the machine was 854.7W. A test was carried out on the fabricated centrifugal casting machine with aluminum alloy and the machine was able to cast 6kg of aluminum alloy and the casting was successful.

  2. 厚壁铸造奥氏体不锈钢管道焊缝超声相控阵检测技术概述%Review of Phased Array Ultrasonic Testing for Thick Wall Cast Austenitic Stainless Steel Pipeline Welds

    Institute of Scientific and Technical Information of China (English)

    林莉; 杨平华; 张东辉; 赵天伟; 杨会敏; 李喜孟

    2012-01-01

    The welding quality of cast austenitic stainless steel (CASS) pipeline welds is critical to nuclear reactors. The mandatory requirements of NDT have been raised in inspection code of nuclear power plant, which is about the welding quality and service condition of CASS welds. However, the complex structure of welds makes the ultrasonic testing of CASS welds challenging. Phased array ultrasonic testing (PAUT) technique is promising to solve this problem. The difficulties of PAUT for thick wall CASS pipeline welds are analyzed, the corresponding key issues and solving strategies are summarized. Furthermore, the research progress and latest research results at home and abroad are described, which provides reference for the PAUT of thick wall CASS pipeline welds.%铸造奥氏体不锈钢(Cast austenitic stainless steel,CASS)管道的焊接质量直接关系到核反应堆的安全,在核动力装置的检验规范中,对此类焊缝加工质量及服役期间状况提出无损检测的强制性要求,但CASS焊缝组织状态的复杂性给超声检测工作带来困难,研究采用相控阵超声检测(Phased array ultrasonic testing,PAUT)技术解决这一难题已成为国内外无损检测工作者关注的热点.概述厚壁CASS管道焊缝PAUT技术的难点,归纳相应的关键技术及解决策略,并简述近期国内外相关研究工作的进展和成果,以期为厚壁CASS管道焊缝的PAUT技术提供借鉴和参考.

  3. 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.)

  4. Higher Education's Caste System

    Science.gov (United States)

    Iannone, Ron

    2004-01-01

    In this article, the author discusses the history of the present caste system in higher education. He shows how the public's perception of this caste system is based on image and not usually on the quality of teaching and curriculum in colleges and universities. Finally, he discusses a model for accessibility to higher education and how higher…

  5. A cast orientation index.

    Science.gov (United States)

    Ivanhoe, J R; Mahanna, G K

    1994-12-01

    This article describes a technique that allows multiple master casts to be precisely oriented to the same path of insertion and withdrawal. This technique is useful in situations where multiple fixed prosthodontic preparations require surveyed restorations and a single master cast is not available.

  6. Caste and power

    DEFF Research Database (Denmark)

    Roy, Dayabati

    2011-01-01

    This paper explores the institution of caste and its operation in a micro-level village setting of West Bengal, an Indian state, where state politics at grass roots level is vibrant with functioning local self-government and entrenched political parties. This ethnographic study reveals that caste...

  7. Numerical Simulation of Cast Distortion in Gas Turbine Engine Components

    Science.gov (United States)

    Inozemtsev, A. A.; Dubrovskaya, A. S.; Dongauser, K. A.; Trufanov, N. A.

    2015-06-01

    In this paper the process of multiple airfoilvanes manufacturing through investment casting is considered. The mathematical model of the full contact problem is built to determine stress strain state in a cast during the process of solidification. Studies are carried out in viscoelastoplastic statement. Numerical simulation of the explored process is implemented with ProCASTsoftware package. The results of simulation are compared with the real production process. By means of computer analysis the optimization of technical process parameters is done in order to eliminate the defect of cast walls thickness variation.

  8. Significance of the  phase for the erosive wear process of the duplex cast steel

    Directory of Open Access Journals (Sweden)

    Z. Stradomski

    2008-10-01

    Full Text Available The work presents a possibility of increasing the tribological properties of the ferritic-austenitic cast steel (the so called duplex cast steel of GX2CrNiMoCu25-6-3-3 grade by taking an advantage of the mechanism of precipitation strengthening with the σ phase arisen due to the eutectoidal ferrite decomposition. The examinations have been held using specimens cut out of both a massive casting (an impeller of about one-ton mass and a thin-walled casting (of the wall thickness about 2 mm. The huge impeller has been made of cast steel containing 0.09% of carbon (i.e. exceeding the demands of the current standard, while the thin-walled casting has been of cast steel withextremely low carbon content (0.024% due to applying the input material of a great purity. Employing the moulding material withalkaline phenolic binder hardened with CO2 and using the zirconia coating has allowed for achieving about 20% fraction of σ phase in the as-cast state of the casting. An increase in σ phase fraction in the structure of duplex cast steel results in improving the abrasive wear resistance of the material. It should be stressed that despite the high fraction of the σ phase in the material, the crack-free castings have been obtained. An addition of copper has made possible producing the high-quality thin-walled (as for cast steel castings of smoothsurfaces. No defects (including shrinkage porosity have been found.

  9. Multi-layers castings

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2010-01-01

    Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

  10. The Applied Example of GBF Polymer Alloy Thin-walled Tube Cast-in-situ Concrete Hollow Floor%GBF高分子合金薄壁管现浇混凝土空心楼盖应用实例

    Institute of Scientific and Technical Information of China (English)

    安娜

    2014-01-01

    在高层公共建筑中,GBF高分子合金薄壁管现浇混凝土空心楼盖得到了越来越广泛的应用。本文结合广州市某信息中心工程实例,介绍了该项目中现浇混凝土空心楼盖施工的要点、难点,并提出解决方法,确保了工程质量。%In public high-rise buildings, GBF polymer alloy thin-waled tube cast-in-place concrete holow floor has been widely used. In this paper, based on the example of an inf- ormation center project in Guangzhou City, the author intr- oduced the key points, difficulties of the project in the co- nstruction of the cast-in-situ concrete holow floor, put forward solutions to ensure the engineering quality.

  11. Quantification of Feeding Effects of Spot Feeding Ductile Iron Castings made in Vertically Parted Moulds

    DEFF Research Database (Denmark)

    Vedel-Smith, Nikolaj Kjelgaard; Tiedje, Niels Skat; Sällström, J.

    In vertically parted molds it is traditionally difficult to feed heavy sections that cannot be reached by traditional side/top feeders or other conventional methods. This project aims at quantifying the effects of using molded-in ram-up spot feeders as a means of feeding isolated sections...... analyses the effect of different exothermic and insulating spot feeders and their interaction with traditional parting line feeders, with respect to porosities and surface shrinkage. Experiments were performed using EN-GJS-500-7 and EN-GJS-450-10 alloys. The experiment shows that the geometry cannot...

  12. Prediction of Microstructure in ADI Castings

    Directory of Open Access Journals (Sweden)

    Guzik E.

    2016-12-01

    Full Text Available Tests were carried out on samples of low-alloy ductile iron with additions of Ni, Cu and Mo, subjected to austempering heat treatment. The samples were austenitized at 850, 900 and 950 °C, and then austempered at T = 210, 240, 270, 300 and 330 °C. The ausferritizing treatment was carried out in a salt bath for the time τ = 2 - 8 hours. Additionally, tests and studies covered samples subjected to the ausferritizing treatment at 270 °C with the time of holding castings in a bath from 2 to 24 hours. Evaluation covered the results of the ADI microstructure examinations and hardness measurements. The ADI matrix morphology was identified counting the average number of ausferrite plates and measuring their width and spacing. The regression equations HB = f (τ, T and τ = f (HB, T were derived to establish the, so-called, “process window”, allowing obtaining a priori the required microstructure of ADI and, consequently, the required mechanical properties, mainly hardness, shaping the functional properties of castings, abrasion wear resistance – in particular.

  13. 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.

  14. 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.

  15. 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.

  16. Caste in Itself, Caste and Class, or Caste in Class

    Directory of Open Access Journals (Sweden)

    Ramkrishna Mukherjee

    2015-08-01

    Full Text Available After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1 the relation of people to land for production (and not for revenue receiving, household living, etc., and (2 the caste system of India, viz. the jati strati?cation of society.

  17. Fluid migration in ductile shear zones

    Science.gov (United States)

    Fusseis, Florian; Menegon, Luca

    2014-05-01

    Fluid migration in metamorphic environments depends on a dynamically evolving permeable pore space, which was rarely characterised in detail. The data-base behind our understanding of the 4-dimensional transport properties of metamorphic rocks is therefore fragmentary at best, which leaves conceptual models poorly supported. Generally, it seems established that deformation is a major driver of permeability generation during regional metamorphism, and evidence for metamorphic fluids being channelled in large scale shear zones has been found in all depth segments of the continental crust. When strain localizes in ductile shear zones, the microfabric is modified until a steady state mylonite is formed that supports large deformations. A dynamic porosity that evolves during mylonitisation controls the distinct transport pathways along which fluid interacts with the rock. This dynamic porosity is controlled by a limited number of mechanisms, which are intrinsically linked to the metamorphic evolution of the rock during its deformational overprint. Many mid- and lower-crustal mylonites comprise polyphase mixtures of micron-sized grains that show evidence for deformation by dissolution/precipitation-assisted viscous grain boundary sliding. The establishment of these mineral mixtures is a critical process, where monomineralic layers are dispersed and grain growth is inhibited by the heterogeneous nucleation of secondary mineral phases at triple junctions. Here we show evidence from three different mid- and lower-crustal shear zones indicating that heterogeneous nucleation occurs in creep cavities. Micro- and nanotomographic observations show that creep cavities provide the dominant form of porosity in these ultramylonites. They control a "granular fluid pump" that directs fluid migration and hence mass transport. The granular fluid pump operates on the grain scale driven by viscous grain boundary sliding, and requires only small amounts of fluid. The spatial arrangement of

  18. 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.

  19. Clean Metal Casting

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

  20. 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.

  1. Effect of inter-critical quenching on mechanical properties of casting low-alloy steel

    Directory of Open Access Journals (Sweden)

    Liu Zhongli

    2013-07-01

    Full Text Available For some casting low-alloy steels, traditional quenching and tempering heat treatments can improve the strength; however, sometimes the ductility is not satisfied. Therefore, some kind of effective heat treatment method seems necessary; one which could improve the ductility, but not seriously affect the strength. In this paper, the effect of inter-critical quenching (IQ on the mechanical properties of casting low-alloy steel was studied. IQ was added between quenching and tempering heat treatment; and the microstructure and mechanical properties were compared to the same steel with the traditional quenching and tempering treatments. The experimental results show that the microstructure comprises small-size ferrite and martensite when the IQ is adopted; and that different temperatures can control the ferrite quantity and distribution, and, as a result, influence the mechanical properties. In the case of IQ, the tensile strength decreases just a little, but the ductility increases a lot; and the strength-ductility product (its value is the arithmetic product of elongation and tensile strength increases by between 6% and 10%, which means the IQ heat treatment can improve comprehensive mechanical properties.

  2. Ultrahigh Ductility, High-Carbon Martensitic Steel

    Science.gov (United States)

    Qin, Shengwei; Liu, Yu; Hao, Qingguo; Zuo, Xunwei; Rong, Yonghua; Chen, Nailu

    2016-10-01

    Based on the proposed design idea of the anti-transformation-induced plasticity effect, both the additions of the Nb element and pretreatment of the normalization process as a novel quenching-partitioning-tempering (Q-P-T) were designed for Fe-0.63C-1.52Mn-1.49Si-0.62Cr-0.036Nb hot-rolled steel. This high-carbon Q-P-T martensitic steel exhibits a tensile strength of 1890 MPa and elongation of 29 pct accompanied by the excellent product of tensile and elongation of 55 GPa pct. The origin of ultrahigh ductility for high-carbon Q-P-T martensitic steel is revealed from two aspects: one is the softening of martensitic matrix due to both the depletion of carbon in the matensitic matrix during the Q-P-T process by partitioning of carbon from supersaturated martensite to retained austenite and the reduction of the dislocation density in a martensitic matrix by dislocation absorption by retained austenite effect during deformation, which significantly enhances the deformation ability of martensitic matrix; another is the high mechanical stability of considerable carbon-enriched retained austenite, which effectively reduces the formation of brittle twin-type martensite. This work verifies the correctness of the design idea of the anti-TRIP effect and makes the third-generation advanced high-strength steels extend to the field of high-carbon steels from low- and medium-carbon steels.

  3. 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.

  4. Determining Ductile Fracture Toughness in Metals

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang [ORNL; Nanstad, Randy K [ORNL; Sokolov, Mikhail A [ORNL; Manneschmidt, Eric T [ORNL

    2014-01-01

    Ductile fracture toughness determination, such as the J-integral versus crack growth resistance (J-R) curve, is a useful tool for evaluating material structural integrity in the presence of pre-existing defects. The J-R curve represents a way to calculate the work (energy) per unit fracture surface area needed to drive the crack growth. A typical J-R curve is shown in Fig. 1 from which the material fracture toughness near the initiation of stable crack growth (Jq) can be derived. In addition, tearing modulus (TR), representing the material resistance to stable crack growth, can be calculated based on the slope of the J-R curve between two exclusion lines (red dashed lines in Fig. 1). Since the introduction of the J-R curve, extensive efforts have been continuously devoted to develop simplified and reliable methods for determining the material J-R curve. This article briefly reviews three widely-used J-R curve test methods in metals, i.e. elastic unloading compliance (EUC), normalization, and direct current potential drop (DCPD). The main difference in these methods relates to the determination of the crack size. More details of performing the J-R curve determination can be found in ASTM standard E1820-11.

  5. Non-local models for ductile failure

    Science.gov (United States)

    César de Sá, José; Azinpour, Erfan; Santos, Abel

    2016-08-01

    Ductile damage can be dealt with continuous descriptions of material, resorting, for example, to continuous damage mechanic descriptions or micromechanical constitutive models. When it comes to describe material behaviour near and beyond fracture these approaches are no longer sufficient or valid and continuous/discontinuous approaches can be adopted to track fracture initiation and propagation. Apart from more pragmatic solutions like element erosion or remeshing techniques more advanced approaches based on the X-FEM concept, in particular associated with non-local formulations, may be adopted to numerically model these problems. Nevertheless, very often, for practical reasons, some important aspects are somewhat left behind, specially energetic requirements to promote the necessary transition of energy release associated with material damage and fracture energy associated to a crack creation and evolution. Phase-field methods may combine advantages of regularised continuous models by providing a similar description to non-local thermodynamical continuous damage mechanics, as well as, a "continuous" approach to numerically follow crack evolution and branching

  6. Symptomatic stent cast.

    Science.gov (United States)

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

    2008-02-01

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  7. CENTRIFUGAL CASTING MACHINE

    Science.gov (United States)

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  8. Symptomatic stent cast.

    LENUS (Irish Health Repository)

    Keohane, John

    2012-02-03

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  9. Development of environmentally friendly cast alloys and composites. High zinc Al-base cast alloys

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2010-01-01

    Full Text Available This work is devoted to grain refinement of the foundry Al-20 wt% Zn (AlZn20 alloy, aiming at improving ductility of the sand-cast alloy The melted alloy was inoculated using traditional AlTi5B1 (TiBAl and AlTi3C0.15 (TiCAl master alloys and newly introduced (Zn,Al-Ti3 one. The performed structural examinations showed out significant increasing of the grain population of the inoculated alloy and plas-ticity increase represented by elongation. The high damping properties of the initial alloy, measured using an ultrasonic Olympus Epoch XT device, are basicly preserved after inoculation. Also tensile strength preserves its good values, while elongation shows an increase – which are beneficials of the employed grain-refining process.

  10. Bainite obtaining in cast iron with carbides castings

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2010-01-01

    Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

  11. Alloy design for intrinsically ductile refractory high-entropy alloys

    Science.gov (United States)

    Sheikh, Saad; Shafeie, Samrand; Hu, Qiang; Ahlström, Johan; Persson, Christer; Veselý, Jaroslav; Zýka, Jiří; Klement, Uta; Guo, Sheng

    2016-10-01

    Refractory high-entropy alloys (RHEAs), comprising group IV (Ti, Zr, Hf), V (V, Nb, Ta), and VI (Cr, Mo, W) refractory elements, can be potentially new generation high-temperature materials. However, most existing RHEAs lack room-temperature ductility, similar to conventional refractory metals and alloys. Here, we propose an alloy design strategy to intrinsically ductilize RHEAs based on the electron theory and more specifically to decrease the number of valence electrons through controlled alloying. A new ductile RHEA, Hf0.5Nb0.5Ta0.5Ti1.5Zr, was developed as a proof of concept, with a fracture stress of close to 1 GPa and an elongation of near 20%. The findings here will shed light on the development of ductile RHEAs for ultrahigh-temperature applications in aerospace and power-generation industries.

  12. Microalloying Boron Carbide with Silicon to Achieve Dramatically Improved Ductility.

    Science.gov (United States)

    An, Qi; Goddard, William A

    2014-12-01

    Boron carbide (B4C) is a hard material whose value for extended engineering applications such as body armor; is limited by its brittleness under impact. To improve the ductility while retaining hardness, we used density functional theory to examine modifying B4C ductility through microalloying. We found that replacing the CBC chain in B4C with Si-Si, denoted as (B11Cp)-Si2, dramatically improves the ductility, allowing a continuous shear to a large strain of 0.802 (about twice of B4C failure strain) without brittle failure. Moreover, (B11C)-Si2 retains low density and high hardness. This ductility improvement arises because the Si-Si linkages enable the icosahedra accommodate additional shear by rotating instead of breaking bonds.

  13. Retention of ductility in high-strength steels

    Science.gov (United States)

    Parker, E. R.; Zackay, V. F.

    1969-01-01

    To produce high strength alloy steel with retention of ductility, include tempering, cooling and subsequent tempering. Five parameters for optimum results are pretempering temperature, amount of strain, strain rate, temperature during strain, and retempering temperature.

  14. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2011-01-01

    White Cast Iron (Ⅰ) White cast iron or ‘white iron' refers to the type of cast iron in which all of the carbon exists as carbide;there is no graphite in the as-cast structure and the fractured surface shows a white colour.White cast iron can be divided in three classes:· Normal white cast iron — this iron contains only C,Si,Mn,P and S,with no other alloying elements.· Low-alloy white cast iron — the total mass fraction of alloying elements is less than 5%.

  15. Influence of phosphorus on the creep ductility of copper

    Energy Technology Data Exchange (ETDEWEB)

    Sandström, Rolf, E-mail: rsand@kth.se [Materials Science and Engineering, KTH, Brinellvägen 23, S-100 44 Stockholm (Sweden); Swerea KIMAB, Box 7074, S-164 07 Kista (Sweden); Wu, Rui [Swerea KIMAB, Box 7074, S-164 07 Kista (Sweden)

    2013-10-15

    Around 1990 it was discovered that pure copper could have extra low creep ductility in the temperature interval 180–250 °C. The material was intended for use in canisters for nuclear waste disposal. Although extra low creep ductility was not observed much below 180 °C and the temperature in the canister will never exceed 100 °C, it was feared that the creep ductility could reach low values at lower temperatures after long term exposure. If 50 ppm phosphorus was added to the copper the low creep ductility disappeared. A creep cavitation model is presented that can quantitatively describe the cavitation behaviour in uniaxial and multiaxial creep tests as well as the observed creep ductility for copper with and without phosphorus. A so-called double ledge model has been introduced that demonstrates why the nucleation rate of creep cavities is often proportional to the creep rate. The phosphorus agglomerates at the grain boundaries and limits their local deformation and thereby reduces the formation and growth of cavities. This explains why extra low creep ductility does not occur in phosphorus alloyed copper.

  16. Ductile streaks in precision grinding of hard and brittle materials

    Indian Academy of Sciences (India)

    V C Venkatesh; S Izman; S Sharif; T T Mon; M Konneh

    2003-10-01

    Ductile streaks produced during diamond grinding of hard and brittle materials have aided the subsequent process of polishing. Two novel techniques were used to study the formation of ductile mode streaks during diamond grinding (primary process) of germanium, silicon, and glass. In the first technique, aspheric surfaces were generated on Ge and Si at conventional speeds (5000 rpm). In the second technique, diamond grinding of plano surfaces on glass and Si surfaces using high speed (100,000 rpm) was carried out. Form accuracy, surface finish and ductile mode grinding streaks are discussed in this paper. It was found that resinoid diamond wheels gave more ductile streaks than metal-bonded wheels but better form accuracy was obtained with the latter. Ductile streaks were obtained more easily with pyrex rather than with BK 7 glass thus necessitating very little time for polishing. Ductile streaks appeared in abundance on germanium rather than silicon. Both the novel grinding techniques were used on CNC machining centres.

  17. 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.

  18. New measurement technique of ductility curve for ductility-dip cracking susceptibility in Alloy 690 welds

    Energy Technology Data Exchange (ETDEWEB)

    Kadoi, Kota, E-mail: kadoi@hiroshima-u.ac.jp [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Uegaki, Takanori; Shinozaki, Kenji; Yamamoto, Motomichi [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan)

    2016-08-30

    The coupling of a hot tensile test with a novel in situ observation technique using a high-speed camera was investigated as a high-accuracy quantitative evaluation method for ductility-dip cracking (DDC) susceptibility. Several types of Alloy 690 filler wire were tested in this study owing to its susceptibility to DDC. The developed test method was used to directly measure the critical strain for DDC and high temperature ductility curves with a gauge length of 0.5 mm. Minimum critical strains of 1.3%, 4.0%, and 3.9% were obtained for ERNiCrFe-7, ERNiCrFe-13, and ERNiCrFe-15, respectively. The DDC susceptibilities of ERNiCrFe-13 and ERNiCrFe-15 were nearly the same and quite low compared with that of ERNiCrFe-7. This was likely caused by the tortuosity of the grain boundaries arising from the niobium content of around 2.5% in the former samples. Besides, ERNiCrFe-13 and ERNiCrFe-15 indicated higher minimum critical strains even though these specimens include higher content of sulfur and phosphorus than ERNiCrFe-7. Thus, containing niobium must be more effective to improve the susceptibility compared to sulfur and phosphorous in the alloy system.

  19. ON MODELLING OF MICROSTRUCTURE FORMATION, LOCAL MECHANICAL PROPERTIES AND STRESS – STRAIN DEVELOPMENT IN ALUMINIUM CASTINGS

    DEFF Research Database (Denmark)

    Svensson, Ingvar; Seifeddine, Salem; Kotas, Petr

    2009-01-01

    inherently affects the component’s properties depending on design, metallurgy and casting method. The wall thickness influences the coarseness of the microstructure and the material will have properties depending on the local metallurgical and thermal histories. This is independent on the material, i.......e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it difficult to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... product has constant material properties throughout the entire casting. Thus, if the microstructure is determined or predicted at a given point, it gives the possibility to calculate the local material behaviour more realistically. The paper shows modelling and simulation of microstructure formation...

  20. Ductile flow by water-assisted cataclasis

    Science.gov (United States)

    den Brok, Bas

    2003-04-01

    In the presence of water otherwise brittle materials may deform macroscopically ductile by water-assisted cataclastic creep. This is possible as long as (i) solubility is high enough, so that stress-corrosion can occur, and (ii) local stress is low enough, to that fracturing remains subcritical. Water-assisted cataclastic creep (WACC) may play an important role in the middle and lower continental crust where mineral solubilities are high and stresses low. WACC is a poorly understood deformation process. Experiments were performed on very soluble brittle salts (Na-chlorate; K-alum) to study microstructure development by WACC. The experiments were carried out at room temperature and atmospheric pressure in a small see-through vessel. In this way the cataclastic deformation process could be studied "in-situ" under the microscope. Crystals were loaded in the presence of saturated salt solution. It appeared that originally straight mineral surfaces were instable when kept under stress. Grooves (or channels) slowly developed in the surface by local dissolution. These grooves behave like so-called Grinfeld instabilities. They develop because the energy of a grooved surface under stress is lower than the energy of a straight surface under stress. The grooves may deepen and turn into subcritical cracks when local stress further increases. These cracks propagate slowly. They propagate parallel to sigma1 but also at an angle and even perpendicular to sigma1, often following crystallographically controlled directions. The fractures mostly change direction while propagating, locally making turns of more than 180 degrees. Irregular fracture fragments thus develop. The fractures may migrate sideways (as with grain bounday migration) probably by solution-redeposition driven by differences in stress between both sides of the fracture. Thus the shape of the fragments changes. The size of the fracture fragments seems to be controlled by the distance of the grooves, which decreases

  1. 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.

  2. 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.

  3. 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.

  4. Influence of the chemical composition of different steel scraps on the mechanical properties of ductile iron; Influencia de la composicion quimica de diferentes chatarras de acero sobre las propiedades mecanicas de la fundicion con grafito esferoidal

    Energy Technology Data Exchange (ETDEWEB)

    Asenjo, I.; Larranaga, P.; Garay, J.; Sertucha, J.

    2011-07-01

    Different commercial steel scraps have been selected so as to analyse the outcome of their use as raw materials and to evaluate their applicability in the production of ductile iron castings. These selected steels show an important chemical variability mainly depending on their origin and on their previous utilisation. According to that, alloying elements added through these materials have been determined and their effects on the structural characteristics and the mechanical properties of test-castings with different shape and size have been studied. The most important element added is manganese, which is included in all the selected scraps with contents higher than 0.2 %. Other elements are: copper, chromium, tin, titanium and vanadium. All of them are known as pearlite promoters apart from titanium and vanadium. Therefore, these elements can be used for manufacturing casting containing pearlitic and/or mixed ferritic and pearlitic structures. No carbides were found in all the test castings. (Author) 20 refs.

  5. 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。

  6. Study of an Al-Si-Cu HPDC alloy with high Zn content for the production of components requiring high ductility and tensile properties

    Energy Technology Data Exchange (ETDEWEB)

    Vicario, Iban; Egizabal, Pedro; Galarraga, Haize; Plaza, Luis Maria; Crespo, Inigo [Fundacion Tecnalia Research and Innovation, Donostia-San Sebastien (Spain). Dept. of foundry processes

    2013-04-15

    Conventional high-pressure die casting aluminium components present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of the castings as well as the presence of iron-based brittle intermetallic phases. The present work approaches the increase in ductility and tensile strength through the analysis of the effect of the alloying elements of AlSi alloys used for high-pressure die casting. The combination of alloying elements providing the best results in terms of ductility and tensile strength were eventually selected to produce a batch of components that were thoroughly tested. The final alloy had a composition of Si 8.21, Fe 0.78, Cu 1.53, Mn 0.64, Mg 0.46, Ni 0.07, Zn 3.37, Pb 0.34, Sn 0.27, Ti 0.18 and Cr 0.04wt.%. The selected alloy performance was compared to that of the commercial AlSi9Cu3 and Silafont {sup registered} 36 alloys.

  7. From brittle to ductile: a structure dependent ductility of diamond nanothread

    Science.gov (United States)

    Zhan, Haifei; Zhang, Gang; Tan, Vincent B. C.; Cheng, Yuan; Bell, John M.; Zhang, Yong-Wei; Gu, Yuantong

    2016-05-01

    As a potential building block for the next generation of devices/multifunctional materials that are spreading in almost every technology sector, one-dimensional (1D) carbon nanomaterial has received intensive research interests. Recently, a new ultra-thin diamond nanothread (DNT) has joined this palette, which is a 1D structure with poly-benzene sections connected by Stone-Wales (SW) transformation defects. Using large-scale molecular dynamics simulations, we found that this sp3 bonded DNT can transition from brittle to ductile behaviour by varying the length of the poly-benzene sections, suggesting that DNT possesses entirely different mechanical responses than other 1D carbon allotropes. Analogously, the SW defects behave like a grain boundary that interrupts the consistency of the poly-benzene sections. For a DNT with a fixed length, the yield strength fluctuates in the vicinity of a certain value and is independent of the ``grain size''. On the other hand, both yield strength and yield strain show a clear dependence on the total length of DNT, which is due to the fact that the failure of the DNT is dominated by the SW defects. Its highly tunable ductility together with its ultra-light density and high Young's modulus makes diamond nanothread ideal for the creation of extremely strong three-dimensional nano-architectures.As a potential building block for the next generation of devices/multifunctional materials that are spreading in almost every technology sector, one-dimensional (1D) carbon nanomaterial has received intensive research interests. Recently, a new ultra-thin diamond nanothread (DNT) has joined this palette, which is a 1D structure with poly-benzene sections connected by Stone-Wales (SW) transformation defects. Using large-scale molecular dynamics simulations, we found that this sp3 bonded DNT can transition from brittle to ductile behaviour by varying the length of the poly-benzene sections, suggesting that DNT possesses entirely different

  8. FRP strengthening of RC walls with openings

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Sas, Gabriel; Täljsten, Björn

    2009-01-01

    Strengthening reinforced concrete (RC) walls with openings using fibre reinforced polymers (FRP) has been experimentally proven to be a viable rehabilitation method. However, very few theoretical investigations are reported. In this paper two methods of analysis are presented. Since openings vary...... in size, the analysis of a strengthened wall can be divided into frame idealization method for large openings, and combined disk and frame analysis for smaller openings. The first method provides an easy to use tool in practical engineering, where the latter describes the principles of a ductile...

  9. Impact of ductility on hydraulic fracturing in shales

    Science.gov (United States)

    MacMinn, Chris; Auton, Lucy

    2016-04-01

    Hydraulic fracturing is a method for extracting natural gas and oil from low-permeability rocks such as shale via the high-pressure injection of fluid into the bulk of the rock. The goal is to initiate and propagate fractures that will provide hydraulic access deeper into the reservoir, enabling gas or oil to be collected from a larger region of the rock. Fracture is the tensile failure of a brittle material upon reaching a threshold tensile stress, but some shales have a high clay content and may yield plastically before fracturing. Plastic deformation is the shear failure of a ductile material, during which stress relaxes through irreversible rearrangements of the particles of the material. Here, we investigate the impact of the ductility of shales on hydraulic fracturing. We first consider a simple, axisymmetric model for radially outward fluid injection from a wellbore into a ductile porous rock. We use this model to show that plastic deformation greatly reduces the maximum tensile stress, and that this maximum stress does not always occur at the wellbore. We then complement these results with laboratory experiments in an analogue system, and with numerical simulations based on the discrete element method (DEM), both of which suggest that ductile failure can indeed dramatically change the resulting deformation pattern. These results imply that hydraulic fracturing may fail in ductile rocks, or that the required injection rate for fracking may be much larger than the rate predicted from models that assume purely elastic mechanical behavior.

  10. Ductile electroactive biodegradable hyperbranched polylactide copolymers enhancing myoblast differentiation.

    Science.gov (United States)

    Xie, Meihua; Wang, Ling; Guo, Baolin; Wang, Zhong; Chen, Y Eugene; Ma, Peter X

    2015-12-01

    Myotube formation is crucial to restoring muscular functions, and biomaterials that enhance the myoblast differentiation into myotubes are highly desirable for muscular repair. Here, we report the synthesis of electroactive, ductile, and degradable copolymers and their application in enhancing the differentiation of myoblasts to myotubes. A hyperbranched ductile polylactide (HPLA) was synthesized and then copolymerized with aniline tetramer (AT) to produce a series of electroactive, ductile and degradable copolymers (HPLAAT). The HPLA and HPLAAT showed excellent ductility with strain to failure from 158.9% to 42.7% and modulus from 265.2 to 758.2 MPa. The high electroactivity of the HPLAAT was confirmed by UV spectrometer and cyclic voltammogram measurements. These HPLAAT polymers also showed improved thermal stability and controlled biodegradation rate compared to HPLA. Importantly, when applying these polymers for myotube formation, the HPLAAT significantly improved the proliferation of C2C12 myoblasts in vitro compared to HPLA. Furthermore, these polymers greatly promoted myogenic differentiation of C2C12 cells as measured by quantitative analysis of myotube number, length, diameter, maturation index, and gene expression of MyoD and TNNT. Together, our study shows that these electroactive, ductile and degradable HPLAAT copolymers represent significantly improved biomaterials for muscle tissue engineering compared to HPLA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. A Study on Ductility of Prestressed Concrete Pier Based on Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    H. Wang

    2016-12-01

    Full Text Available The ductility of prestressed concrete pier is studied based on response surface methodology. Referring to the pervious prestressed concrete pier, based on Box-Behnken design, the ductility of 25 prestressed concrete piers is calculated by numerical method. The relationship between longitudinal reinforcement ratio, shear reinforcement ratio, prestressed tendon quantity, concrete compressive strength and ductility factor is gotten. The influence of the longitudinal reinforcement ratio, the shear reinforcement ratio, the prestressed tendon quantity and concrete compressive strength to curvature ductility is discussed. Then the ductility regression equation is deduced. The result showed that the influence of the prestressed tendon quantity to the ductility of prestressed concrete pier is significant. With the increasing of the prestressed tendon quantity, the curvature ductility curved reduces. With the increasing of shear reinforcement ratio and compressive strength of concrete, the curvature ductility increases linearly. And the influence of the longitudinal reinforcement ratio to ductility of the prestressed concrete pier is insignificant.

  12. Melt Cast High Explosives

    Directory of Open Access Journals (Sweden)

    Stanisław Cudziło

    2014-12-01

    Full Text Available [b]Abstract[/b]. This paper reviews the current state and future developments of melt-cast high explosives. First the compositions, properties and methods of preparation of trinitrotoluene based (TNT conventional mixtures with aluminum, hexogen (RDX or octogen (HMX are described. In the newer, less sensitive explosive formulations, TNT is replaced with dinitroanisole (DNANDNANDNAN and nitrotriazolone (NTONTONTO, nitroguanidine (NG or ammonium perchlorate (AP are the replacement for RDRDX and HMX. Plasticized wax or polymer-based binder systems for melt castable explosives are also included. Hydroxyl terminated polybutadiene (HPTB is the binder of choice, but polyethylene glycol, and polycaprolactone with energetic plasticizers are also used. The most advanced melt-cast explosives are compositions containing energetic thermoplastic elastomers and novel highly energetic compounds (including nitrogen rich molecules in whose particles are nanosized and practically defect-less.[b]Keywords[/b]: melt-cast explosives, detonation parameters

  13. Simulation of fuzzy control systems for nonferrous alloy vacuum counter-pressure casting

    Institute of Scientific and Technical Information of China (English)

    YAN Qing-song; CAI Qi-zhou; WEI Bo-kang; YU Huan; YU Zi-rong

    2005-01-01

    Through simulation analyses of vacuum counter-pressure casting fuzzy control systems based on MATLAB, fuzzy control systems designed by simulation can track technical route established well. When transmission functions of vacuum counter-pressure casting controlled objects are changed in operation, fuzzy control systems can carry on self-regulation and stabilize quickly, and embody the advantages of fleet response velocity and little adjusting quantity. The design of vacuum counter-pressure casting fuzzy control systems is accelerated and improved greatly by simulation based on MATLAB. Meanwhile, their design is accurate and reliable. Moreover, microstructure and properties of thin-wall aluminum alloy castings are improved effectively by using fuzzy control systems.

  14. Casting Characteristics of Aluminum Die Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  15. Brittle and ductile friction and the physics of tectonic tremor

    Science.gov (United States)

    Daub, E.G.; Shelly, D.R.; Guyer, R.A.; Johnson, P.A.

    2011-01-01

    Observations of nonvolcanic tremor provide a unique window into the mechanisms of deformation and failure in the lower crust. At increasing depths, rock deformation gradually transitions from brittle, where earthquakes occur, to ductile, with tremor occurring in the transitional region. The physics of deformation in the transition region remain poorly constrained, limiting our basic understanding of tremor and its relation to earthquakes. We combine field and laboratory observations with a physical friction model comprised of brittle and ductile components, and use the model to provide constraints on the friction and stress state in the lower crust. A phase diagram is constructed that characterizes under what conditions all faulting behaviors occur, including earthquakes, tremor, silent transient slip, and steady sliding. Our results show that tremor occurs over a range of ductile and brittle frictional strengths, and advances our understanding of the physical conditions at which tremor and earthquakes take place. Copyright ?? 2011 by the American Geophysical Union.

  16. Brittle to ductile transition in densified silica glass.

    Science.gov (United States)

    Yuan, Fenglin; Huang, Liping

    2014-05-22

    Current understanding of the brittleness of glass is limited by our poor understanding and control over the microscopic structure. In this study, we used a pressure quenching route to tune the structure of silica glass in a controllable manner, and observed a systematic increase in ductility in samples quenched under increasingly higher pressure. The brittle to ductile transition in densified silica glass can be attributed to the critical role of 5-fold Si coordination defects (bonded to 5 O neighbors) in facilitating shear deformation and in dissipating energy by converting back to the 4-fold coordination state during deformation. As an archetypal glass former and one of the most abundant minerals in the Earth's crest, a fundamental understanding of the microscopic structure underpinning the ductility of silica glass will not only pave the way toward rational design of strong glasses, but also advance our knowledge of the geological processes in the Earth's interior.

  17. Hot Ductility of the 17-4 PH Stainless Steels

    Science.gov (United States)

    Herrera Lara, V.; Guerra Fuentes, L.; Covarrubias Alvarado, O.; Salinas Rodriguez, A.; Garcia Sanchez, E.

    2016-03-01

    The mechanisms of loss of hot ductility and the mechanical behavior of 17-4 PH alloys were investigated using hot tensile testing at temperatures between 700 and 1100 °C and strain rates of 10-4, 10-2, and 10-1 s-1. Scanning electron microscopy was used in conjunction with the results of the tensile tests to find the temperature region of loss of ductility and correlate it with cracking observed during processing by hot upsetting prior to ring rolling. It is reported that 17-4 PH alloys lose ductility in a temperature range around 900 °C near to the duplex austenite + ferrite phase field. Furthermore, it is found that niobium carbides precipitated at austenite/ferrite interfaces and grain boundaries have a pronounced effect on the mechanical behavior of the alloy during high-temperature deformation.

  18. An Improved Ductile Fracture Criterion for Fine-blanking Process

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen; ZHUANG Xin-cun; XIE Xiao-long

    2008-01-01

    In order to accurately simnulate the fine-blanking process,a suitable ductile fracture is significant.So an evaluation strategy based on experimental and corresponding simulation results of tensile,compression,torsion and fine-blanking test is designed to evaluate five typical ductile fracture criteria,which are widely-used in metal forming process.The stress triaxiality and ductile damage of each test specimen are analyzed.The results show that none of these five criteria is sufficient for all tests.Furthermore,an improved fracture criterion based on Rice and Tracey model,taking the influence of both volume change and shape change of voids into account,is proposed.The characterization of this model for fine-blanking process is easily done by the tensile test and the prediction result shows good.

  19. A new freeze casting technique for ceramics

    Science.gov (United States)

    Araki, Kiyoshi

    A new freeze casting technique for ceramics capable of manufacturing near room temperature with a sublimable vehicle has been developed in order to eliminate expensive processes under extremely cold temperatures in the conventional freeze casting. Fluid concentrated slurries of Al2O 3 powder in molten camphene (C10H16) were successfully prepared at 55°C with a small amount of a dispersant. These slurries were quickly solidified (frozen) at room temperature to yield a rigid solid green body, where the frozen camphene was easily removed by sublimation (freeze-drying) with negligible shrinkage. Sintering was successfully conducted without any special binder burnout process to yield dense sintered bodies (over 98% T.D). An organic alloy with a eutectic composition in the naphthalene (C 10H8)-camphor (C10H16O) binary system with a eutectic temperature of 31°C was also found to be a successful vehicle for the new ceramic freeze casting. The fabrication processes are almost the same as those with camphene. It was found that vehicles with off-eutectic compositions resulted in large voids in the sintered body due to the ceramic particle rejection by pro-eutectic crystals during freezing. At the eutectic composition, fine lamellar microstructure in the solidified vehicle inhibits the particle rejection. The proposed advantages of the new freeze casting technique with a sublimable vehicle include; (1) elimination of extremely cold temperatures used in conventional freeze casting; (2) elimination of troublesome binder burnout process; and (3) fast manufacturing cycle due to quick solidification. Porous ceramic bodies with unique interconnected pore channels were fabricated by the new freeze casting with lower solid content. The unique channels surrounded by fully dense walls have nearly circular cross-sections unlike conventional aqueous freeze casting. The porosity and the channel diameters are controllable by the solid content in the slurry. The unique channels are

  20. Development of Flexible Link Slabs using Ductile Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi

    emphasis oncrack formation and development at the rebar-matrix interface during direct tensile loading. Utilizing a high definition DIC technique in a novel approach, detailed measurements of the crack formation and debonding process are obtained. It is found that ductile ECC, in contrast to conventional...... two adjacent bridge deck segments. The link slab element, composed of GFRP reinforced ECC,exhibited the same tension stiffening and tension strengthening behavior with limited crack widths as was observed in the reinforced prisms under monotonic and cyclic loading. The combination of ductile ECC...