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| 3. |
- Diaconu, Lucian Vasile, et al.
(författare)
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Influence of molybdenum alloying on thermomechanical fatigue life of compacted graphite irons
- 2012
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Ingår i: International Journal of Cast Metals Research. - : Maney Publishing. - 1364-0461 .- 1743-1336. ; 25:5, s. 277-286
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Tidskriftsartikel (refereegranskat)abstract
- In this study four compacted graphite irons (CGIs) and one grey cast iron (FGI) were produced and tested in the laboratory. The molybdenum content of the four CGI grades was varied between 0 and 1·01 wt-%. The purpose of the investigations was to examine the effect of the different molybdenum contents of the CGI on the thermomechanical fatigue (TMF) behaviour. The TMF tests were performed by cycling a constrained specimen between 110 and 600°C. For every material three tests were performed on specimens machined from a Ø20 mm cylinder. Other tests were performed on specimens machined from Ø55 mm and Ø85 mm cylinders respectively. The tests showed that additions of molybdenum improved the fatigue resistance of CGI. It was observed that additions of molybdenum refined the pearlite and that the specimens with a finer metallic matrix had a higher TMF resistance.
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| 4. |
- Diaconu, Lucian Vasile, et al.
(författare)
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Stress relaxation of compacted graphite iron alloyed with molybdenum
- 2013
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Ingår i: International Journal of Cast Metals Research. - : Taylor & Francis. - 1364-0461 .- 1743-1336. ; 26:1, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, the thermomechanical fatigue resistance of four compacted graphite irons (CGIs) and one grey cast iron was investigated. The molybdenum content of the four CGIs varied between 0 and 1.01 wt-%. It was observed that during thermal cycling, the maximum value of the compressive stress continuously decreased while the value of the maximum tensile stress continuously increased. The continuous decrease in compressive stresses showed that stress relaxation occurs at elevated temperatures during thermal cycling. The goal of the present investigation was to investigate the phenomenon of stress relaxation at elevated temperatures. The tests were performed at 350 and 600uC respectively. The results of the stress relaxation tests performed at 600uC showed the same trend observed at thermomechanical fatigue testing. The tests showed that additions of molybdenum improved the fatigue resistance of CGI by lowering the stress relaxation rate.
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| 6. |
- Diószegi, Attila, 1962-, et al.
(författare)
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Microstructures and Characterization of Gray Irons
- 2017
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Ingår i: ASM Handbook, Volume 1A. - Materials Park, Ohio : ASM International. - 9781627081337 - 162708133X - 9781627081344 ; , s. 583-589
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Bokkapitel (refereegranskat)
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| 7. |
- Diószegi, Attila, 1962-, et al.
(författare)
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Prediction of volume fraction of primary austenite at solidification of lamellar graphite cast iron using thermal analyses
- 2016
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Ingår i: Journal of thermal analysis and calorimetry (Print). - : Springer Netherlands. - 1388-6150 .- 1588-2926. ; 124:1, s. 215-225
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Tidskriftsartikel (refereegranskat)abstract
- Lamellar graphite cast iron was investigated with carbon equivalents varied between CE = 3.4 and 4.26, cast at various cooling rates between 0.195 and 3.5 °C s-1 covering the limits used for technical applications in the production of complex-shaped lamellar graphite cast iron. Registered cooling curves displaced in two positions in the casting were used to predict the solidification and microstructure formation mechanisms. The predicted volume fraction of primary austenite was compared with the fraction of primary austenite measured on colour micrographs with the help of image analyses. A good correlation has been obtained for medium and slow cooling conditions, while a less good correlation at fast cooling condition was attributed to the used protective environment to preserve thermocouples. The observed fraction and the predicted fraction of primary austenite were in good correlation and followed a consequent variation dependent on the carbon equivalent. Furthermore, the quality of the prediction was dependent on the used numerical algorithm involving cooling information from either one or two thermocouples.
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| 9. |
- Fourlakidis, Vasilios, et al.
(författare)
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Strength prediction of lamellar graphite iron : From Griffith’s to hall-petch modified equation
- 2018
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Ingår i: Materials Science Forum. - : Trans Tech Publications. - 0255-5476 .- 1662-9752. - 9783035710557 ; , s. 272-279
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Konferensbidrag (refereegranskat)abstract
- Traditionally, ultimate tensile strength (UTS) is used as the main property for the characterization of lamellar graphite iron (LGI) alloys under static loads. The main models found in the literature for predicting UTS of pearlitic lamellar graphite iron are based on either regression analysis on experimental data or on modified Griffith or Hall-Petch equation. In pearlitic lamellar graphite iron the primary austenite dendritic network, transformed to pearlite, reinforces the bulk material while the distance between those pearlite grains, defines the maximum continuous defect size in the bulk material. Recently the novel parameter of the Diameter of Interdendritic Space has been used to express the flow length in a modified Griffith equation for the prediction of the UTS in LGI. Nevertheless this model neglects the strengthening effect of the pearlite lamellar spacing within the perlite grains. A model based on modified Hall-Petch equation was developed in this work. The model considers the effect of both microstructure parameters and covers a broad spectrum of microstructure sizes typical for complex shape castings with various wall thicknesses.
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| 10. |
- Hellström, Kristina, et al.
(författare)
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A broad literature review of density measurements of liquid cast iron
- 2017
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Ingår i: Metals. - : MDPI. - 2075-4701. ; 7:5
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Forskningsöversikt (refereegranskat)abstract
- The literature on density measurements, with a particular interest in methods suitable for liquid cast iron, is reviewed. Different measurement methods based on a number of physical properties are highlighted and compared. Methods for the calculation of density are also reviewed, and the influence of alloying elements on density is, to some extent, discussed. The topic is of essence for the understanding of the material behaviour at solidification, which is pivotal in software applications for casting simulation. Since a deeper understanding of the relationship between the density of liquid cast iron and volume expansion is necessary, the conclusion that further research within the field is needed lies close at hand.
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