Influence of Vanadium and Tungsten on the Bainite start temperature

Transcription

1 Influence of Vanadium and Tungsten on the Bainite start temperature Author: Andreas Malmberg Mentors: Mats Hillert and Lars Höglund

2 Abstract This paper tries to display the influence of the alloying elements, Vanadium and Tungsten, on the bainite transformation start temperature (Bs). The purpose of this work was to establish data of interaction parameters to be part of newly created computer software called Bs-program which will be used to calculate the banite start temperature in steel alloys. This will be achieved by extensive literature studies and analysis of the data gathered. The data will then be used to calculate the transformation barrier (B) for bainite transformation and try to differentiate the influence of Vanadium and Tungsten on this Barrier. These calculations gave quite clear results for the Vanadium steels and interaction parameters could be isolated. As for the Tungsten steels it proved hard to find the Tungsten influence as Vanadium was present in the majority of those steels. Key words: Bainite start temperature, Transformation Barrier, Influence, Vanadium, Tungsten 1

3 Table of content Introduction... 3 Method... 4 How does one acquire Bs-temperatures?... 4 Gathering of values... 4 Calculations Calculation of G in the Bs-program Models created in Matlab... 7 Result... 8 Methods to determine Bs-temperature Metallographic observation Dilatometry C content calculated from lattice parameter of austenite measured by X-ray diffraction... 9 List of Vanadium and Tungsten Steels... 9 Influence calculations Vanadium Tungsten Discussion Conclusion Acknowledgement References Appendix

4 Introduction For the last decades the industrial production and engineering of steel have gone through a huge transformation as a result of the exponential growth of the computer industry. The increased capacity of computers and understanding of software programing have enabled an integration of engineering problems with computer simulations, resulting in software like Thermo-Calc and Dictra. These softwares can be used in the processing industries to calculate complex multicomponent systems more effectively. Companies discovered that a great deal of money could be saved and production capacity could be increased by integrating these kinds of softwares. This project is a subproject of a bigger project within the Hero-m initiative. The project objective is to create computer software with the ability to make a good estimation of the bainite start temperature (Bs) for steel alloys called the Bs-program 1. In order to achieve this, an understanding of the different influences of alloying elements on the Bs-temperature is vital. The general perception of bainite transformation is that formation of Widmanstätten ferrite is the start of bainite transformation and that perception will be used in this report as well. This report concerns the influence of the elements Vanadium and Tungsten with the objective to establish a model of the influence by creating plots and, if the result is satisfying, interaction parameters will be calculated and be part of the software. This will be achieved by a literature study of steel alloys containing various amounts of vanadium and tungsten, searching for TTT-diagrams and tables. CCT diagrams will not be a source to values in this report as the error margin of the start transformation temperature is too big when dealing with continuous cooling. It s also important to understand how these literature values have been acquired so a brief investigation regarding the most common methods of determine the Bs-temperature will be presented. Because of a very limited number of steels containing only Fe-C-Cr-Mo-V and Fe-C-Cr-Mo-W, other elements are allowed but preferably small amounts as these elements will be neglected when calculating the influence of V and W. All element contents presented in this report will be given in weight % if not specified as something else. 1 Bs-program is used internally at the institution of material science and engineering, KTH, and is under development. 3

5 Method How does one acquire Bs-temperatures? First stage in the project was to understand different measuring methods to acquire Bs-temperature values. This was done by reading reports concerning determination of transformation temperature and characteristics for example a report by Peter Kolmskog, 2013[1] and report by R.C Cochrane and W.B Morrison [2]. The methods found during the gathering of Vanadium and Tungsten steels were then further investigated and summarized with pros and cons. Gathering of values The second step was to gather values from the literature concerning Bs, composition, austenite conditions and method of achieving the values. Values of Bs from TTT diagrams were interpreted and then included in excel with the composition of the steel, the austenitization conditions and source. 83 different steels were interpreted and registered in excel, not all with austenitization condition though. To further investigate these steels and their structure before the banite transformation, an equilibrium calculation was made in Thermo-Calc [3] and the database TCFE7 [4] was used. This was only done with the steels in which an austenitization temperature could be found in the literature. The reason for the equilibrium investigation was a suspicion of carbides in the austenite as some of the steels found had the same compositions but a different austenitization temperature, giving a wide variety in the Bs-temperature. Calculations From the equilibrium calculations, phases, their composition and volume percentage of the different phases could be gathered and put into an excel table. The calculated phases were then compared with the literature value to see if the composition of the austenite had been altered remarkably by the austenitization treatment. If that would be the case, it should be decided how well one could trust the literature information that had not been tested by equilibrium calculations. Calculation of G in the Bs-program The values gathered were then used to calculate the energy barrier for bainite transformation. This was done in the Bs-program [5] that has been developed by Lars Höglund. The thermodynamic theory behind the calculation of transformation barrier was explained by Mats Hillert [6] in an interview and also in a report by C. Garcia-Mateo s [7]. The theory can be summarized that there has to be a critical driving force to start nucleation or growth of bainite. The simple equilibrium between γ and α is pictured in figure 2 and the black dot displays the T 0 in figure 3. The bainite structure is far from equilibrium, though. According to basic thermodynamics the lowest free energy would occur if transformation to grain boundary ferrite took place instead of bainitic ferrite. The reason for bainite forming instead of grain boundary ferrite is the influence of kinetics as Widmanstätten ferrite (W-α) can grow much faster, because of the lower surface energy in the flat surfaces of the plates and shorter distance for carbon atoms to diffuse at the edge than in the case of grain boundary ferrite growth, illustrated in figure 1. 4

6 γ W-α γ grain α Figure 1, Simple illustration of the difference in growth of Widmanstätten ferrite and grain boundary ferrite. The red arrows indicates the growth direction and the blue arrows the diffusion of carbon atoms. The figure was made in word. G m T=T 1 γ µ B α µ A α α + γ γ A B Figure 2, General Gibbs energy curve to illustrate thermodynamic equilibrium between two phases α and γ at temperature T 1. Gibbs molar energy on the y-axis and mol% of B increasing on the x-axis. 5

7 T T 1 WB s T 0 u B Figure 3, a general example of a phase diagram and the difference between the standard equilibrium and the metastable equilibrium at WB s. The existence of a barrier implies that an excess energy is present that makes it possible for bainite to form. It can be described as a metastable equilibrium where austenite (γ) is in equilibrium with Widmanstätten ferrite (W-α). Imagine that Bs occurs at a temperature and composition displayed by the red dot in figure 2. A new tangent is drawn to illustrate the metastable equilibrium with W-α, displayed in figure 3. γ µ B α G µ A α α + γ γ A B Figure 4, Illustrates the change of the Gibbs curve when metastable equilibrium occurs with W-α instead of grain boundary α and the Barrier ( G) that the transformation has to overcome. 6

8 It becomes apparent that the Gibbs energy curve for α has to be moved up in order to be in a state of equilibrium. So there has to be a driving force of G where, G has to overcome the barrier (B) that is represented by large influence on either growth or nucleation to induce the transformation. This G will be calculated in the Bs-program for the gathered values and put into a table for comparison. The influence on this Barrier from the alloying elements can be described as, where u i is the amount of element i and f i (T) is the parameter for interaction which is a function of temperature. is the temperature dependent barrier of the binary system Fe-C which is well defined in the Bs-program. This will be the fundamental approach for calculating the influence of Vanadium and Tungsten. The barrier as a function of the elements with known effects, C, Mo and Cr and the temperature will first be calculated. Then the barrier as a function of bainite start temperature (Bs) will be calculated and the difference between these will give the influence on the barrier from the element with unknown effect in this case Vanadium. Models created in Matlab With values of barrier influence and composition of the different steels the software Matlab was used to create models and curves of the influence of V and W contents on the G barrier. Vectors of the B s -temperature values, %V and were imported to Matlab. The majority of Tungsten steels found in the literature contained Vanadium as well as Tungsten so correction terms from the Vanadium steel calculations will be isolated before calculations with the Tungsten steels. Plots of the barrier as a function of content of Vanadium will be created to see if a general tendency could be observed. Then a function will be fitted to the points to illustrate the correction terms for Vanadium. B will be normalised with Vanadium content and made as a function of transformation temperature. A spline function for will be fitted to the normalised values and plotted. This will give the correction terms for the same kind of calculations with the Tungsten steels. The code for calculation of the spline functions was supplied by Lars Höglund [8]. 7

9 Result Methods to determine Bs-temperature During the gathering of values of Bs for different alloys three different methods to determine transformation start temperature were discovered. In Atlas zur wärmebehandlung der stähle [9] the TTT-diagrams were created with metallographic observation and Dilatometry which were found commonly mentioned in other reports as well. Another method mentioned is C content calculated in retained austenite from lattice parameter measured by X-ray diffraction. Metallographic observation When determining the Bs in a TTT-diagram with Metallographic observation you treat the steel isothermally and look at the transformation that has occurred. This can be done with optical microscope, scanning electron microscope or transmission electron microscope for example. This makes for a margin of error in the values brought forth with this method as it s sometimes very hard to distinguish the start of the Bainitic transformation with an optical microscope as pearlite can influence the Bainite transformation as described in Peter Kolmskog s report [1]. The perception of the viewer will be an aspect that can contribute to error. Dilatometry As explained in a report by Ahmed Ismail Zaky Farahat [10], during a phase transformation a small change in the volume of the sample will change, this change can be measured by a dilatometer. This makes it possible to determine with quite good accuracy when a phase transition occurs. During the phase transformation the computer linked to the dilatometer will produce a graph giving you the Dilation as a function of time. Making it possible to determine the start temperatures for different phase transformations with rather ease. Figure 5, Illustrates the data output from a Dilatometry test, this figure was published by Ahmed Ismail Zaky Farahat[10] 8

10 A negative aspect of Dilatometry is the need to compliment with microscopy to understand what phases are actually forming at the different temperatures. When making TTT diagrams you use a quenching type of dilatometer, to get an isothermal treatment of the steel. Figure 6, displays the isothermal heat treatment when using quenching type of dilatometer, Ahmed Ismail Zaky Farahat published this graph in journal, [10] C content calculated from lattice parameter of austenite measured by X-ray diffraction The third method discovered is based on the fact that C content in the lattice makes the lattice expand as the C atoms dissolve interstitially resulting in an increase in the lattice parameter which is explained by M.Onink, 1993 [11]. This expansion of the lattice can be measured by X-ray or neutron diffraction. So when a sample of steel is heat-treated and carbon enrichment of austenite starts, an increase in lattice size this can be seen which is an indication that ferrite is forming. If that ferrite is Widmanstätten ferrite the perception that W-α transformation is a part of the bainite transformation gives a Bs-temperature. List of Vanadium and Tungsten Steels After gathering values from different steels containing vanadium and tungsten from the literature, a table was created displaying the different steels and it can be seen in table 1(appendix). Along with the values of Bs-temp, austinitization temperature, composition and source you can also see the method used to create the TTT-diagrams or tables. The equilibrium calculations in Thermo-Calc made it evident that there are carbides and phases other than austenite present in most of the steels when quenched. The new composition of the austenite and amount of different phases is displayed in table 2(appendix). Due to the fact that the difference in Vanadium and Tungsten content between the literature values and equilibrium calculations was quite extensive, only the equilibrium values will be used for further investigation. They are displayed in table 3 and table 4 for Vanadium steels and Tungsten steels, some of the steels containing very low contents of V and W have also been disregarded in further calculations. 9

11 Vanadium steels Steel nr. Bs [⁰C] %C %Cr %Mo %V 4 594,00 0,430 0,320 0,030 0, ,00 0,440 1,701 0,080 0, ,00 0,550 1, , ,00 0,470 1,200 0,050 0, ,00 0,470 1, , ,00 0,377 5,530 0,864 0, ,00 0,390 5,531 0,870 0, ,00 0,430 1,310 0,720 0, ,00 0,430 1,310 0,720 0, ,00 0,380 1,540 0,630 0, ,00 0,520 1,090 0,430 0, ,00 1,150 1, , ,00 0,565 1,265 0,019 0, ,00 0,580 1,270 0,020 0, ,00 0,145 1, ,288 Table 3, list of the Vanadium steels that have been analysed and determined good enough for further calculations Tungsten Steels Steel nr. Bs [⁰C] %C %Cr %Mo %V %W ,00 0,786 0,778 0, , ,00 0,460 1,530 0, , ,00 0,625 4,119 2,301 1,111 2, ,00 0,724 4,077 2,409 1,557 2, ,00 0,53 4,66 0,39 1,02 6, ,00 0,58 4,17 0,46 1,48 5, ,00 0,28 2,35 0,06 0,53 4, ,00 0,23 2,59 0,02 0,30 6, ,00 0,44 1,28 0,04 0,05 0, ,00 0,35 1,45 0,46 0,52 0, ,00 0,57 3,94 0,21 0,70 7, ,00 0,59 4,28 2,57 1,32 2,62 Table 4, list of Tungsten steels that have been analysed and determined good enough for further calculations 10

12 Influence calculations Vanadium The results from the calculation of the transformation barrier of bainite in the Bs-program with regard to the Vanadium steels are displayed in table 5. The Barrier values in the second column represent tabulated values of what the barrier should be with regard to the temperature conditions and Fe-C-Cr-Mo alloy content. In the third column the calculated value of the Barrier is represented and the difference between these columns gives the influence of Vanadium on the barrier. It s important to point out that the barrier values calculated is influenced by temperature, C content, Cr content, Mo content as well as the aimed V content. Steel nr 20 proved to have a negative barrier influence and will be neglected in further calculations as it contained rather high carbon content in comparison to Vanadium content. Vanadium Steel nr. Barrier, B(u,T) Barrier, B(B s ) Vanadium influence 4 605,4 792,5 187, , , , , ,7 108, ,5 899,8 99, , , ,9 859,4 46, ,7 169,7 Table 5, the result of the barrier influence of the Vanadium steels Figure 7 shows the result of Matlab plot with the Vanadium steels. The calculation of correction terms for Vanadium on the transformation barrier is illustrated in figure 8 and from this spline function generated in the plot, can be isolated and put into vectors seen in table 4. This correction term can then be put into the Bs-program script and new Influence parameters from the Tungsten steels can be calculated. 11

13 Figure 7, plot to see the general tendency of Vanadium s (V) effect on the Barrier (B) Figure 8, Illustrates the spline function that has been fitted to the Vanadium content normalised black crosses. Interaction parameters of Vanadium Temperature Barrier influence Table 6, the values used to create the spline curve in figure 8, these values will be put into the Bs-program script for calculations with the Tungsten steels. 12

14 Tungsten In table 7 the barrier calculations with the Tungsten steels is presented although, almost all of the Tungsten steels contained Vanadium so a correction of Vanadium is necessary. The interaction parameters for Vanadium were incorporated in the Bs-program and a new influence calculation was executed, the result can be seen in table 8. These values could then be imported to Matlab and the resulting plot can be seen in figure 9. Tungsten, without V correction Steel nr. Barrier, B(u,T) Barrier, B(B s ) Tungsten influence , , Table 7, influence calculations of tungsten steels without taking Vanadium content into consideration Tungsten, with V correction Steel nr. Barrier, B(u,T) Barrier, B(B s ) Tungsten influence , , Table 8, the influence calculations of the Tungsten steels when influence of Vanadium is taken into consideration and removed. 13

15 Figure 8, plot to see the general tendency of tungsten influence on the barrier, the line indicates zero influence on the barrier. The (V) in the top right corner indicates that not all steels contained V but the majority. 14

16 Discussion The methods of determining Bs-temperature found during the research are used extensively and have been proved as good methods. Metallographic observation and Dilatometry was the method used in most of the TTT-diagrams found. These two methods complement each other well as the difficulties of distinguishing the start transformation in a light transmission microscope can be complemented with Dilatometry, which measures with quite good accuracy when transformation takes place but not what phase that s transforming. The information on the TTT-diagrams didn t say what kind of dilatometer or microscope that was used but as the date of publishing the data was one could make assumptions that the dilatometer was of an early design and not as accurate as todays equipment. The microscope used was probably a light emission microscope (LEM) if usage of electron transmission microscope of atom probe microscope would have been used instead, more accurate data would have been gathered. The method of calculating the C content by the lattice parameter measured with X-ray diffraction can be improved by changing X-ray diffraction with neutron diffraction which will give a more accurate result when dealing with high temperatures as neutrons penetrate and probe more of the material. The Literature values gathered from TTT-diagrams and tables was proven when equilibrium calculated to have quite different compositions of Vanadium and Tungsten in the austenite. This is due to the strong tendency of V and W to form carbides and to make further calculations proper only the equilibrium values was used. As a result of this the number of values was reduced drastically from 57 to 15 Fe-C-Cr-Mo-V steels. Number of Fe-C-Cr-Mo-V-W steels was reduced from 27 to 12. If this would have been discovered earlier, new literature studies could have been executed in order to compensate for this loss of data. A question mark has to be raised regarding the already integrated interaction parameters of temperature, carbon, chromium and molybdenum. All new influence calculations with this method are strongly dependent of these parameters so an error in these will quickly propagate through new interaction parameters. But although it s important to take this source of error into consideration the method have proven to give a good approximation of the influence. When plotting the influence of Vanadium a clear tendency could be seen although a rather rough approximation of the influence correction was made because of the limited number of data points. As for the Tungsten steels the results obtained from the influence calculations after removing the evaluated effect of V were hard to interpret. Very low values and even negative values can be seen with rather high %W. As for Tungsten content below 1 wt% a relative high barrier was calculated, so these results should not be trusted. It should be noted that the content of V in the majority of the Tungsten steels is much higher than in the Vanadium steels used to evaluate the effect of Vanadium subtracted from the Tungsten steels. It thus seems impossible to separate the effects of V and W with this method if the data of Vanadium steels and Tungsten steels can t be more coincident. An effort should be made to find data of steels containing a higher V content without W and data concerning W without V. 15

17 Conclusion The results from this work should then be treated as a guide line for further research on this subject. More extensive literature study should be made and the analysis of the values gathered should be done during this study. This will enable compensation for loss of data due to unreliable values from old experiments. The Vanadium influence result shows a clear tendency but lacks values of higher Vanadium content so it should only be trusted as an approximation for steels with low Vanadium content. When trying to separate Vanadium influence from Tungsten influence its necessary to first determine the Influence of Vanadium with more certainty as most of the industrially produced steels with Tungsten content generally seams to contain Vanadium as well. Acknowledgement Thanks to Mats Hillert for pedagogic and interesting discussions and guidance, a lot of knowledge has been embedded into a young man s brain thanks to him. Lars Höglund s great patience and expertise when explaining computer programing and methodology have been crucial for keeping this work within the timeframe. Also thanks to Peter Kolmskog for helping with the literature study by sharing his own studies for his doctoral thesis. 16

18 References [1]. Thermodynamic analysis of the critical conditions for acicular ferrite authors: Peter Kolmskog, Annika Borgenstam, Lars Höglund and Mats Hillert [2]. Influence of vanadium on transformation characteristics of high-strength line-pipe steels, Published in Metals technology in December, 1981 authors: R.C. Cochrane and W. B. Morrison [3]. Thermo-Calc Software version 3.0, software package used for thermodynamic calculations of multicomponent systems. Calculations are based on thermodynamic databases produced by expert evaluation of experimental data using the CALPHAD method. [4]. Database TCFE7, version 7.0 Database containing information of steel and Fe alloy design and processing. [5]. Bs-program, Software currently under development by Lars Höglund with team. It is used internally at the institute of Material Science and Technology at KTH. The program uses Thermo-Calc interface and database TCFE6. [6]. Mats Hillert Ph.D at department of Material science and engineering. [7]. New approach for the bainite start temperature calculation in steels] Published in Materials Science and Technology, volume 21, Year: 2005 authors: C. Garcia-Mateo, T.Sourmail, F.G. Gaballero, C.Capdevila and C. García de Andrés [8]. Lars Höglund, Ph.D at department of Material science and engineering. [9]. Atlas zur wärmebehandlung der sthäle, ISBN: authors: Adolf Rose, Walter Peter, Werner Strassburg, Leo Rademacher [10]. Dilatometry determination of phase transformation temperatures during heating of Nb bearing low carbon steel, Published in Journal of materials processing technology 204, 2008 author: Ahmed Ismail Zaky Farahat [11]. The lattice parameters of austenite and ferrite in Fe-C alloys as a function of carbon content and temperature, Published in Scripta Metallurgica et Materialia vol.29, 1993 authors: M.Onink, C.M. Brakman, F.D. Tichelar, E.J. Mittemeijer, S.Van der Zwaag, J.H. Root, N.B.Konyer [12]. The temperature of Formation of Martensite and Bainite in Low-alloy Steels, published in Journal of the Iron and steel institute in august, 1956 authors: W. Steven and A.G. Haynes [13]. Atlas of time-temperature diagrams for irons and steels, ISBN: author: G.F. Vander Voort 17

19 Appendix 18

20 19

21 Table 1. Literature values Steel nr. Year Source Bs [⁰C] %C %Mn %Cr %Mo %V %W %Ni %Si %S %P %Cu %Al %N %Ti %Co Austinitization [⁰C] Method [12] Tabel 1&6 ref ,00 0,51 0,72 0,94 0,05 0,20 0,00 0,15 0,27 0,02 0,02 0,00 0,00 0,00 0,00 0,00 875,00 Dilatometry and metallographic observation [12] Tabel 1&6 ref ,00 0,40 0,52 1,25 1,00 0,15 0,00 1,83 0,23 0,00 0,01 0,00 0,00 0,00 0,00 0,00 860,00 Dilatometry and metallographic observation [9] II-103D 589,00 0,43 1,67 0,32 0,03 0,10 0,00 0,11 0,28 0,01 0,02 0,06 0,00 0,00 0,00 0,00 870,00 Dilatometry and metallographic observation [9] II-103D 594,00 0,43 1,67 0,32 0,03 0,10 0,00 0,11 0,28 0,01 0,02 0,06 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-112D 539,00 0,44 0,75 1,70 0,08 0,09 0,00 0,17 0,26 0,02 0,02 0,18 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-113D 544,00 0,55 0,98 1,02 0,00 0,11 0,00 0,01 0,22 0,01 0,02 0,07 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-113H 555,00 0,47 1,04 1,20 0,05 0,12 0,00 0,05 0,35 0,01 0,03 0,16 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-113H 567,00 0,47 0,82 1,20 0,00 0,11 0,00 0,04 0,35 0,02 0,04 0,14 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-121D 600,00 0,16 1,12 0,99 0,02 0,01 0,00 0,12 0,22 0,01 0,03 0,00 0,02 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-123D 567,00 0,16 0,50 1,95 0,03 0,01 0,00 2,02 0,31 0,01 0,01 0,00 0,03 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-204D 350,00 0,39 0,48 5,53 0,87 0,48 0,00 0,04 0,94 0,01 0,01 0,30 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-204D 372,00 0,39 0,48 5,53 0,87 0,48 0,00 0,04 0,94 0,01 0,01 0,30 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-205D 489,00 0,43 0,75 1,31 0,72 0,23 0,00 0,11 0,27 0,01 0,01 0,00 0,00 0,00 0,00 0,00 970,00 Dilatometry and metallographic observation [9] II-205D 500,00 0,43 0,75 1,31 0,72 0,23 0,00 0,11 0,27 0,01 0,01 0,00 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-205G 500,00 0,38 0,81 1,54 0,63 0,27 0,00 0,01 0,18 0,01 0,02 0,00 0,00 0,00 0,00 0,00 970,00 Dilatometry and metallographic observation [9] II-206D 561,00 0,52 0,70 1,09 0,43 0,14 0,00 1,72 0,29 0,01 0,01 0,00 0,00 0,00 0,00 0,00 850,00 Dilatometry and metallographic observation [9] II-206D 461,00 0,52 0,70 1,09 0,43 0,14 0,00 1,72 0,29 0,01 0,01 0,00 0,00 0,00 0,00 0,00 950,00 Dilatometry and metallographic observation [9] II-222D 411,00 2,08 0,39 11,48 0,02 0,04 0,00 0,31 0,28 0,01 0,02 0,15 0,00 0,00 0,00 0,00 970,00 Dilatometry and metallographic observation [9] II-222D 389,00 2,08 0,39 11,48 0,02 0,04 0,00 0,31 0,28 0,01 0,02 0,15 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-224D 528,00 1,42 0,61 1,37 0,00 0,18 0,00 0,00 0,37 0,02 0,02 0,04 0,00 0,00 0,00 0,00 950,00 Dilatometry and metallographic observation [9] II-226D 522,00 1,03 0,97 1,05 0,03 0,00 1,15 0,13 0,28 0,02 0,02 0,25 0,00 0,00 0,00 0,00 815,00 Dilatometry and metallographic observation [9] II-227D 566,00 0,58 0,81 1,27 0,02 0,11 0,00 0,06 0,89 0,01 0,01 0,14 0,00 0,00 0,00 0,00 870,00 Dilatometry and metallographic observation [9] II-227D 511,00 0,58 0,81 1,27 0,02 0,11 0,00 0,06 0,89 0,01 0,01 0,14 0,00 0,00 0,00 0,00 950,00 Dilatometry and metallographic observation [9] II-229D 466,00 0,40 0,35 1,27 0,24 0,04 0,00 4,03 0,20 0,02 0,01 0,16 0,00 0,00 0,00 0,00 860,00 Dilatometry and metallographic observation [9] II-229D 450,00 0,40 0,35 1,27 0,24 0,04 0,00 4,03 0,20 0,02 0,01 0,16 0,00 0,00 0,00 0,00 950,00 Dilatometry and metallographic observation [9] II-229G 417,00 0,46 0,50 1,53 0,07 0,00 0,59 3,96 0,24 0,01 0,01 0,20 0,00 0,00 0,00 0,00 860,00 Dilatometry and metallographic observation [9] II-261D 350,00 0,97 0,18 4,11 2,61 2,51 3,23 0,25 0,31 0,01 0,04 0,00 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-261D 344,00 0,97 0,18 4,11 2,61 2,51 3,23 0,25 0,31 0,01 0,04 0,00 0,00 0,00 0,00 0, ,00 Dilatometry and metallographic observation [9] II-321D 661,00 0,15 0,67 1,20 0,00 0,31 0,00 0,25 0,48 0,02 0,04 0,18 0,00 0,00 0,00 0,00 920,00 Dilatometry and metallographic observation [13] sida 161 nedre 340,00 0,80 0,30 4,34 0,78 1,52 17,89 0,30 0,23 0,01 0,02 0,00 0,00 0,00 0,00 4, , [13] sida: 160 nedre 360,00 0,87 0,32 3,99 0,80 2,52 11,91 0,11 0,27 0,01 0,02 0,00 0,00 0,00 0,00 0, , [13] sida:154 övre 560,00 0,52 0,70 1,09 0,43 0,14 0,00 1,72 0,29 0,01 0,01 0,00 0,00 0,00 0,00 0,00 850, [13] sida: ,00 0,28 0,39 2,35 0,06 0,53 4,10 0,06 0,16 0,01 0,02 0,00 0,00 0,00 0,00 0, , [13] sida: ,00 0,28 0,36 2,57 0,03 0,35 8,88 0,04 0,11 0,00 0,01 0,00 0,00 0,00 0,00 0, , [13] sida: ,00 0,55 0,34 1,27 0,05 0,18 2,10 0,12 0,94 0,01 0,02 0,00 0,00 0,00 0,00 0,00 950, [13] sida: ,00 0,39 0,45 1,45 0,47 0,70 0,55 0,13 0,58 0,00 0,02 0,00 0,00 0,00 0,00 0, , [13] sida: ,00 0,81 0,33 3,77 0,44 1,07 18,25 0,12 0,15 0,00 0,02 0,00 0,00 0,00 0,00 0, , [13] sida: ,00 0,85 0,31 4,15 4,79 2,01 6,34 0,18 0,30 0,01 0,02 0,00 0,00 0,00 0,00 0, , [13] sida: ,00 0,30 0,30 1,63 0,49 0,08 0,00 3,64 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 840, [1] Hackenberg 600,00 0,30 0,00 0,00 0,00 0,00 6,30 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,40 0,00 5,25 0,00 0,00 4,25 0,00 1,15 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] Hultgren 480,00 0,59 0,00 0,00 0,00 0,00 3,62 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [1] ASM p ,00 0,55 0,55 0,00 0,00 0,00 1,96 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Dilatometry [1] Hultgren 590,00 0,55 0,00 0,00 0,00 0,00 1,96 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [12] Tabel 1&6 ref ,00 0,32 0,47 1,21 0,30 0,01 0,00 4,13 0,29 0,02 0,02 0,00 0,00 0,00 0,00 0,00 _ Dilatometry and metallographic observation [1] US Steel p ,00 0,32 0,47 1,21 0,30 0,01 0,11 4,13 0,29 0,00 0,00 0,51 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,32 0,47 1,21 0,30 0,01 0,11 4,13 0,29 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [1] US Steel p ,00 0,32 0,61 0,63 0,22 0,03 0,16 3,22 0,28 0,00 0,00 0,12 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,32 0,61 0,63 0,22 0,03 0,16 3,22 0,28 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [12] Tabel 1&6 ref ,00 0,32 0,61 0,63 0,22 0,03 0,00 3,22 0,28 0,03 0,02 0,00 0,00 0,00 0,00 0,00 _ Dilatometry and metallographic observation [13]. sida: ,00 0,40 0,35 1,27 0,24 0,04 0,00 4,03 0,20 0,02 0,01 0,16 0,00 0,00 0,00 0,00 _ [1] Rees 346,00 0,44 0,67 0,39 0,83 0,09 0,00 1,85 1,74 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] Peet 200,00 0,75 1,95 1,48 0,28 0,10 0,00 0,00 1,63 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ C content calculated from lattice parameter [1] ASM p ,00 0,27 0,84 0,73 0,90 0,11 0,00 0,60 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [1] US Steel p ,00 0,59 0,96 1,06 0,54 0,12 0,00 0,00 0,28 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [12] Tabel 1&6 ref ,00 0,36 0,56 1,22 0,31 0,13 0,00 1,46 0,16 0,03 0,01 0,00 0,00 0,00 0,00 0,00 _ Dilatometry and metallographic observation

22 [1] ASM p ,00 0,43 0,74 0,92 0,00 0,16 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,25 0,52 1,14 0,65 0,16 0,00 3,33 0,15 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,25 0,52 1,14 0,65 0,16 0,00 3,33 0,15 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [12] Tabel 1&6 ref ,00 0,25 0,52 1,14 0,65 0,16 0,00 3,33 0,15 0,02 0,01 0,00 0,00 0,00 0,00 0,00 _ Dilatometry and metallographic observation [1] ASM p ,00 0,53 0,67 0,93 0,00 0,18 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Dilatometry [12] Tabel 1&6 ref ,00 0,32 0,51 1,37 0,48 0,18 0,00 3,02 0,19 0,01 0,01 0,00 0,00 0,00 0,00 0,00 _ Dilatometry and metallographic observation [1] US Steel p ,00 0,32 0,51 1,37 0,48 0,18 0,00 3,02 0,19 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,51 0,72 0,94 0,05 0,20 0,11 0,15 0,27 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 1,50 0,00 11,50 0,80 0,20 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,45 0,70 1,00 0,00 0,20 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 2,25 0,00 11,50 0,80 0,20 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,40 1,34 0,53 0,22 0,21 0,00 1,03 0,21 0,00 0,00 0,08 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,23 0,82 1,22 0,53 0,22 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,40 0,78 1,25 0,53 0,22 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] ASM p ,00 0,25 0,88 0,73 0,88 0,23 0,00 0,59 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ Metallographic observation [1] US Steel p ,00 1,55 0,27 11,34 0,53 0,24 0,00 0,00 0,45 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,97 0,48 4,58 1,04 0,25 0,00 0,00 0,40 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 1,00 0,40 5,25 1,15 0,40 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,55 0,00 3,90 0,45 0,90 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] Liu 525,00 0,42 0,00 0,00 0,00 1,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,73 0,21 4,39 0,18 1,09 17,80 0,00 0,33 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,40 0,00 5,00 1,35 1,10 0,00 0,00 1,05 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,72 0,27 4,09 0,00 1,25 18,59 0,00 0,39 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,81 0,24 4,10 4,69 1,64 5,95 0,00 0,26 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,80 0,23 4,07 6,09 1,65 5,70 0,00 0,27 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,85 0,00 4,00 8,00 1,90 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _ [1] US Steel p ,00 0,73 0,00 4,00 0,00 2,00 14,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 _

23 Table 2. Equilibrium results Steel nr Phases %Pase [VOL%] Bs [⁰C] %C %Mn %Cr %Mo %V %W %Ni %Si %S %P %Cu %Al 1 FCC_A1#1 99,751% 560,00 0,481% 0,721% 0,935% 0,048% 0,076% 0,150% 0,270% 0,021% FCC_A1#2 0,249% 16,615% 0,058% 3,932% 1,311% 68,468% 0,000% 0,000% 0,000% 2 FCC_A1#1 99,709% 450,00 0,370% 0,514% 1,251% 0,911% 0,064% 1,834% 0,231% 0,000% 0,008% FCC_A1#2 0,083% 14,887% 0,032% 2,284% 23,609% 54,467% 0,004% 0,000% 0,000% 0,000% MC_ETA#1 0,195% 14,242% 51,421% 34,338% MNS#1 0,014% 63,100% 36,856% 3 FCC_A1#1 99,928% 589,00 0,425% 1,657% 0,320% 0,030% 0,077% 0,110% 0,280% 0,000% 0,021% 0,060% FCC_A1#2 0,045% 16,753% 0,122% 1,193% 0,924% 72,355% 0,000% 0,000% 0,000% 0,000% 0,000% MNS#1 0,027% 63,130% 36,856% 0,000% 4 FCC_A1#1 99,973% 594,00 0,430% 1,657% 0,320% 0,030% 0,100% 0,110% 0,280% 0,000% 0,021% 0,060% MNS#1 0,027% 63,060% 36,855% 0,000% 5 FCC_A1#1 99,936% 539,00 0,440% 0,718% 1,701% 0,080% 0,090% 0,170% 0,260% 0,000% 0,016% 0,180% MNS#1 0,064% 62,949% 36,855% 0,000% 6 FCC_A1#1 99,956% 544,00 0,550% 0,958% 1,020% 0,110% 0,010% 0,220% 0,000% 0,017% 0,070% MNS#1 0,044% 62,997% 36,855% 0,000% 7 FCC_A1#1 99,960% 555,00 0,470% 1,020% 1,200% 0,050% 0,120% 0,050% 0,350% 0,000% 0,032% 0,160% MNS#1 0,040% 63,005% 36,855% 0,000% 8 FCC_A1#1 99,949% 567,00 0,470% 0,795% 1,200% 0,110% 0,040% 0,350% 0,000% 0,035% 0,140% MNS#1 0,051% 62,965% 36,855% 0,000% 9 FCC_A1#1 99,973% 600,00 0,160% 1,107% 0,990% 0,020% 0,010% 0,120% 0,220% 0,000% 0,030% 0,015% MNS#1 0,027% 63,024% 36,855% 10 FCC_A1#1 99,953% 567,00 0,160% 0,476% 1,951% 0,030% 0,010% 2,021% 0,310% 0,000% 0,013% 0,030% MNS#1 0,047% 62,839% 36,854% 11 FCC_A1#1 99,872% 350,00 0,377% 0,472% 5,530% 0,864% 0,425% 0,040% 0,941% 0,000% 0,013% 0,300% FCC_A1#2 0,111% 15,571% 0,023% 6,613% 8,438% 65,732% 0,000% 0,000% 0,000% 0,000% 0,000% MNS#1 0,017% 62,893% 36,854% 0,000% 12 FCC_A1#1 99,983% 372,00 0,390% 0,472% 5,531% 0,870% 0,480% 0,040% 0,940% 0,000% 0,013% 0,300% MNS#1 0,017% 62,693% 36,853% 0,000% 13 FCC_A1#1 99,963% 489,00 0,430% 0,731% 1,310% 0,720% 0,230% 0,110% 0,270% 0,000% 0,011% MNS#1 0,037% 63,053% 36,855% 14 FCC_A1#1 99,963% 500,00 0,430% 0,732% 1,310% 0,720% 0,230% 0,110% 0,270% 0,000% 0,011% MNS#1 0,037% 62,955% 36,855% 15 FCC_A1#1 99,971% 500,00 0,380% 0,797% 1,540% 0,630% 0,269% 0,010% 0,180% 0,000% 0,021% FCC_A1#2 0,001% 15,906% 0,047% 2,540% 8,833% 68,376% 0,000% 0,000% 0,000% 0,000% MNS#1 0,027% 63,063% 36,855% 16 FCC_A1#1 99,760% 561,00 0,496% 0,684% 1,086% 0,411% 0,048% 1,723% 0,291% 0,000% 0,010% FCC_A1#2 0,206% 15,753% 0,053% 4,000% 12,917% 59,004% 0,005% 0,000% 0,000% 0,000% MNS#1 0,034% 63,114% 36,856% 17 FCC_A1#1 99,966% 461,00 0,520% 0,683% 1,090% 0,430% 0,140% 1,720% 0,290% 0,000% 0,010% MNS#1 0,034% 63,055% 36,855%

24 18 FCC_A1#1 81,503% 411,00 0,683% 0,353% 4,052% 0,009% 0,003% 0,372% 0,339% 0,000% 0,021% 0,182% M7C3#1 18,457% 8,732% 0,448% 46,856% 0,070% 0,215% 0,018% 0,000% MNS#1 0,040% 62,946% 36,855% 0,000% 19 FCC_A1#1 83,484% 389,00 0,856% 0,360% 5,121% 0,012% 0,006% 0,363% 0,332% 0,000% 0,020% 0,178% M7C3#1 16,477% 8,727% 0,424% 46,014% 0,063% 0,226% 0,021% 0,000% MNS#1 0,040% 62,744% 36,853% 0,000% 20 CEMENTITE#1 4,997% 6,738% 0,921% 7,551% 1,631% 0,000% FCC_A1#1 94,952% 528,00 1,150% 0,567% 1,056% 0,106% 0,389% 0,000% 0,025% 0,042% MNS#1 0,050% 63,032% 36,855% 0,000% 21 CEMENTITE#1 3,443% 6,682% 1,766% 9,165% 0,073% 1,139% 0,015% 0,000% FCC_A1#1 96,051% 522,00 0,786% 0,920% 0,778% 0,016% 0,306% 0,135% 0,292% 0,000% 0,017% 0,261% MC_SHP#1 0,444% 6,209% 1,360% 92,432% MNS#1 0,062% 63,129% 36,856% 0,000% 22 FCC_A1#1 99,847% 566,00 0,565% 0,801% 1,265% 0,019% 0,049% 0,060% 0,891% 0,000% 0,013% 0,140% FCC_A1#2 0,132% 16,573% 0,068% 6,906% 0,562% 63,916% 0,000% 0,000% 0,000% 0,000% 0,000% MNS#1 0,020% 63,110% 36,856% 0,000% 23 FCC_A1#1 99,980% 511,00 0,580% 0,800% 1,270% 0,020% 0,110% 0,060% 0,890% 0,000% 0,013% 0,140% MNS#1 0,020% 63,065% 36,855% 0,000% 24 FCC_A1#1 99,949% 466,00 0,400% 0,324% 1,271% 0,240% 0,040% 4,032% 0,200% 0,000% 0,010% 0,160% MNS#1 0,051% 63,064% 36,855% 0,000% 25 FCC_A1#1 99,949% 450,00 0,400% 0,325% 1,271% 0,240% 0,040% 4,032% 0,200% 0,000% 0,010% 0,160% MNS#1 0,051% 62,940% 36,855% 0,000% 26 FCC_A1#1 99,976% 417,00 0,460% 0,488% 1,530% 0,070% 0,590% 3,961% 0,240% 0,000% 0,012% 0,200% MNS#1 0,024% 63,091% 36,855% 0,000% 27 FCC_A1#1 96,605% 350,00 0,625% 0,176% 4,119% 2,301% 1,111% 2,692% 0,258% 0,320% 0,001% 0,036% FCC_A1#2 3,195% 12,832% 0,010% 3,916% 11,629% 50,954% 18,668% 0,001% 0,000% 0,000% 0,000% M6C#1 0,182% 2,209% 2,978% 21,800% 3,810% 39,835% 0,007% 0,097% MNS#1 0,018% 61,180% 36,844% 28 LIQUID#1 2,143% 2,532% 0,243% 5,996% 5,283% 5,311% 6,425% 0,181% 0,213% 0,255% 0,109% FCC_A1#1 95,892% 344,00 0,724% 0,182% 4,077% 2,409% 1,557% 2,907% 0,256% 0,318% 0,001% 0,034% FCC_A1#2 1,966% 12,982% 0,010% 3,717% 10,735% 53,072% 17,615% 0,002% 0,000% 0,000% 0,000% 29 FCC_A1#1 99,878% 661,00 0,145% 0,630% 1,201% 0,288% 0,250% 0,480% 0,000% 0,044% 0,180% FCC_A1#2 0,040% 16,517% 0,022% 1,357% 78,277% 0,000% 0,000% 0,000% 0,000% 0,000% MNS#1 0,082% 63,079% 36,855% 0,000% 30 FCC_A1#1 86,48% 340,00 0,53% 0,37% 4,66% 0,39% 1,02% 6,62% 0,37% 0,28% M6C#1 13,52% 1,90% 3,05% 2,39% 3,59% 64,06% 0,03% 0,01% 31 FCC_A1#1 91,24% 360,00 0,58% 0,36% 4,17% 0,46% 1,48% 5,30% 0,12% 0,31% FCC_A1#2 1,36% 12,07% 0,02% 2,95% 1,89% 50,64% 30,93% 0,00% 0,00% M6C#1 7,40% 1,93% 0,00% 2,63% 3,35% 5,61% 62,47% 0,01% 0,01% 32 FCC_A1#1 99,79% 560,00 0,50% 0,70% 1,09% 0,41% 0,05% 1,72% 0,29% FCC_A1#2 0,21% 15,76% 0,05% 3,99% 12,86% 59,07% 0,00% 0,00% 33 FCC_A1#1 100,00% 480,00 0,28% 0,39% 2,35% 0,06% 0,53% 4,10% 0,06% 0,16% 34 FCC_A1#1 97,84% 473,00 0,23% 0,37% 2,59% 0,02% 0,30% 6,56% 0,04% 0,11%

25 M6C#1 2,16% 1,78% 0,00% 1,90% 0,19% 1,77% 70,28% 0,00% 0,00% 35 FCC_A1#1 99,06% 500,00 0,44% 0,35% 1,28% 0,04% 0,05% 0,83% 0,12% 0,95% FCC_A1#2 0,30% 12,78% 0,02% 3,52% 0,76% 46,14% 31,74% 0,00% 0,00% MC_SHP#1 0,65% 6,19% 0,95% 92,86% 36 FCC_A1#1 99,66% 500,00 0,35% 0,45% 1,45% 0,46% 0,52% 0,53% 0,13% 0,58% FCC_A1#2 0,34% 15,26% 0,02% 1,61% 4,15% 68,78% 7,31% 0,00% 0,00% 37 FCC_A1#1 87,43% 347,00 0,57% 0,41% 3,94% 0,21% 0,70% 7,14% 0,14% 0,18% M6C#1 12,57% 1,85% 0,00% 3,03% 1,44% 2,66% 66,70% 0,01% 0,00% 38 FCC_A1#1 91,20% 347,00 0,59% 0,35% 4,28% 2,57% 1,32% 2,62% 0,20% 0,32% FCC_A1#2 0,89% 13,00% 0,02% 3,73% 11,78% 53,04% 16,54% 0,00% 0,00% M6C#1 7,91% 2,24% 0,00% 3,03% 23,33% 4,29% 37,57% 0,00% 0,11% 39 FCC_A1#1 99,98% 450,00 0,30% 0,30% 1,63% 0,49% 0,07% 3,64% FCC_A1#2 0,02% 15,82% 0,02% 4,44% 10,94% 62,07% 0,01%