The FactSage FSstel steel alloy database
The elements included in the FactSage FSstel steel database are:
Al, B, Bi, C, Ca, Co, Cr, Cu, Fe, H, Hf, Mg, Mn, Mo, N, O, Nb, Ni, P, Pb, S, Sb, Si, Sn, Ta, Ti, V, W, Zn, Zr, RE (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)
The FactSage FSstel steel database is based on relevant steel sub-systems from the old SGTE Solution database, but now incorporates updates of those systems as well as new published assessments. “Tramp elements” have also been included to allow calculations relating to recycling and removal of unwanted impurities to be performed.
The database contains 379 completely assessed 61 partially assessed binary alloy systems, together with approximately 158 ternary and 28 quaternary systems for which assessed parameters are available for phases of practical relevance. It contains 186 solution phases and 1014 stoichiometric compounds.
The liquid phase is described by the Modified Quasichemical Model (MQM) since FSStel 7.3 version. With this model, many previous optimizations with the random mixing model and new optimizations with the MQM can be combined to give a more accurate description of the liquid solution in binary, ternary and higher-order systems. The thermodynamic behaviors of O, N, S, and P in liquid steel are well described by this model. For the accurate description of the deoxidation of Fe-Ca and Fe-Mg liquid solutions, CaO and MgO associate species as proposed by Jung, Degterov and Pelton [1], have been incorporated in the liquid phase.
Updates in FactSage 8.3 version
In this update, numerous binary Cr-RE (RE = Rare Earth elements) system were newly added as part of our continue effort to put RE in steel database. Many binary systems containing Ca, Mg, Nb and Zn were newly added or updated for more accurate chemical reaction calculations in the refining process of super alloys and Zn galvanizing process of high alloyed steels. Binary systems containing Sc were also largely updated. These include 47 new binary systems, and several new ternary systems. 2 new solution phases and 57 new compounds are included in 8.3 version.
(1) Cr-RE systems:
a. Cr-RE (RE = Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Y, Yb)
(2) Systems containing Ca, Mg, Sc, and Zn:
a. Ca containing system: Ca-Co, Ca-Cr, Ca-Mo, Ca-Ni, Ca-P, Ca-Sn, Ca-Ta, Ca-Ti, Ca-V, Ca-W
b. Mg containing system: Mg-Mo, Mg-P, Mg-Ta, Mg-W
c. Sc containing system: Sc-Co, Sc-Mo, Sc-Ni, Sc-V
d. Zn containing system: Zn-Mo, Zn-Ni, Zn-S, Zn-Ti, Zn-V, Zn-W, Zn-Y, Zn-Zr
(3) Other systems: Sn-S, Mo-Pb, Cu-Mo, Cu-Nb
(4) Ternary systems: Fe-Zn-S, Fe-Zn-Zr, Al-Nb-Ni
Note from the previous update 8.2 version
In this update, numerous binary systems of Fe-RE, Mn-RE, Co-RE, Ni-RE, Si-RE, Al-RE, and Mg-RE (RE = Rare Earth elements) were newly added. Many key binary, ternary and multi-component systems covering Fe-Cr-Mo-Nb-Ni-Ta system were newly added or updated for better phase diagram calculations in super alloys. The database related to Nd magnet (Fe-Nd-B-Dy-Pr-Tb) and its recycling process using liquid metal was added in this update. These include 87 new binary, 7 updated binary,10 new ternary, and several new quaternary and high order systems. 11 new solution phases and 452 new compounds are included in 8.2 version.
(1) New systems containing rare earth elements:
a. Fe-RE (RE = Ce, Dy, Er, Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Tm, Y)
b. Mn-RE (RE = Ce, Dy, Er, Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Tm, Y)
c. Co-RE (RE = Ce, Dy, Er, Gd, Ho, La, Nd, Pr, Sm, Y)
d. Ni-RE (RE = Ce, Dy, Er, Gd, Ho, La, Nd, Pr, Sm, Tb, Y)
e. Si-RE (RE = Ce, Dy, Er, Gd, Ho, La, Nd, Pr, Sc, Sm, Tb, Tm, Y)
f. Al-RE (RE = Ce, Dy, Er, Eu, Gd, Ho, Lu, Nd, Pr, Sc, Sm, Tb, Tm, Y, Yb)
g. Mg-RE (RE = Ce, Dy, Nd, Pr, Tb)
h. Ternary Fe-La-Si system
(2) Nd magnet related systems:
a. New Fe-Nd-Dy-B quaternary system including small amount of Pr, Tb, Cu, Ni, Co, etc., and reaction with liquid Mg.
b. B-Sn, B-Pb, B-Zn, B-Dy, B-Tb, B-Pr, B-Nd, B-Mg, Mg-Ni, etc.
(3) Super alloy systems:
a. New update of existing binary system: Mo-Ni, Fe-Ta, Ni-Ta, etc.
b. New ternary systems: Cr-Nb-Ni, Mo-Ni-Ta, Fe-Ni-Ta, Mo-Nb-Ni
Note from the previous update 8.1 version:
In this update, the FCC, BCC, Sigma and Laves C14 solutions in many ternary and multicomponent systems including the Co-Cr-Fe-Mn-Ni-V-W system were newly added and updated for the high alloyed steel applications and high entropy alloys (HEAs) applications. This includes 22 new binary and 41 ternary systems, and 25 new solution phases and 38 new compounds.
(1) New binary systems: Al-Hf, B-Si, Bi-Cu, Bi-Sn, C-Ca, Co-Mg, Co-P, Co-V, Co-Zn, Co-Zr, Cr-Sn, Cu-W, Fe-Hf, Hf-Si, Mg-Ni, Mg-Sn, Mg-Zn, Mn-Mo, Mn-Nb, Mn-W, Ni-Sn, Nb-Ta.
(2) New updates to existing binary systems: Al-Nb, Co-N, Fe-Mo, Mo-V, Ni-Sn, Sb-Zn, Ta-V, W-Zr, etc.
(3) Major new ternary and updated ternary systems: Al-Fe-Zr, C-Co-V, C-Cr-Mn, C-Cr-Mo, C-Cu-Fe, C-V-W, C-W-Zr, Co-Cr-Fe, Co-Cr-V, Co-Fe-V, Co-Fe-Zn, Co-Ni-V, Co-N-W, Cr-Fe-Mo, Cr-Fe-W, Cr-Mn-Ti, Cr-Mo-Ni, Cr-Ni-W, Cu-Fe-Ni, Fe-Mn-Nb, Fe-Ni-Si, Fe-Ni-Zr, Mo-N-Nb, etc.
Note from the previous update 8.0 version:
In this update, the following systems have been completely re-assessed to reproduce recent experimental data for high alloyed steels and other steel systems:
(1) Correction of the phase boundary of FCC order/disorder transition in Al-Fe system. No significant change in any Fe-rich region in FSStel 73.
(2) Addition of binary M-H systems where M = Al, Cr, Cu, Fe, Mg, Ni, Si, Ti, V, and Zr. Liquid, FCC, BCC and HCP solutions and important metal hydrate phases were included. In addition, liquid phase in the Ca-H and Zn-H system were included.
(3) Update of Al-C-Cr-Fe-Mn-Ni-Si-P system for high P-containing system (many binary and ternary systems and several quaternary systems containing P have been revised)
Binaries: Al-P, Cr-P, Fe-P, Mn-P, Ni-P, Si-P
Ternaries: Fe-Mn-P, Al-Fe-P, Fe-Si-P, C-Fe-P, Cr-Fe-P, Fe-Ni-P
(4) Updates of Al-C-Fe-Mn-Si-N system for high N-containing system (several systems were updated)
Binaries: Al-N, C-N, Si-N
Ternary: Al-Fe-N, C-Fe-N, C-N-Si, Fe-N-Si, Mn-N-Si, Fe-Mn-N, Fe-N-P
Quaternary: Al-Fe-N-Si, many quaternary systems with liquid only
Higher order system: Al-C-Fe-Mn-N-Si
(5) Updates of Al-Co-Cr-Fe-Ni-Ti system for BCC-B2 and FCC-L12 containing alloys (many binary and ternary systems containing FCC and BCC order/disorder transitions were updated). This system is also well connected to Mn. The new database can give satisfactory results for high entropy alloys (HEAs) of Al-Co-Cr-Fe-Mn-Ni, MCrAlY alloys, and other high alloys
Binary: Al-Co (FCC is slightly changed)
Ternaries: Al-Co-Ni, Al-Cr-Ni, Al-Cr-Ti, Co-Cr-Ni, Co-Ni-Ti
(6) Al-Fe-Zn-Mg-Si-H (all binary systems and key ternary systems) for Zn galvanizing and new AlMgSi galvanizing alloy systems
No significant update was made but addition of hydrogen in liquid was made (see above (2))
(7) Minor update for several systems: Ni-Zr, Sn-Ti, Sn-V, Si-Sn-Ti
Note from the previous Updates in FactSage 7.3 version
In this update, the following systems have been completely re-assessed to reproduce recent experimental data for high alloyed steels and other steel systems:
(1) Al-C-Fe-Mn-Si (entire binary, ternary and quaternary systems) For high Mn, Si, Al alloyed steel
(2) Al-C-Fe-Mn-Si-N (all binary and ternary systems and several quaternary systems containing N) For high N-containing systems
(3) Al-C-Cr-Fe-Mn-Ni-Si-P (all binary and ternary systems and several quaternary systems containing P) For high P-containing systems
(4) Fe-Ni-Cr-Co-Cu-S (entire range of sulfur containing systems) For high S-containing systems
(5) Al-Co-Cr-Fe-Ni-Ti (all binary systems containing FCC and BCC order/disorder transitions and several key ternary systems including the Fe-Al-Ni system) For BCC-B2 containing high strength steel
(6) Al-Fe-Zn-Mg-Si (all binary systems and key ternary systems) For Zn galvanizing and new galvanizing alloy systems
(7) Al-Cr-Cu-Fe-Mg-Mn-Si (entire binary, ternary and higher-order systems)
As such, the database is intended to provide a sound basis for calculations covering a wide range of steel production processes, e.g.
- phase diagrams and phase transitions in a wide range of commercial steel compositions including stainless steels, and new advanced steels under development.
- conditions for heat treatment operations to produce a desired constitution
- chemical reaction to reduce oxygen, sulphur, phosphorous, and hydrogen concentration levels in liquid steel through refining process in liquid state: sometime combinations of FSStel, FTOxid and FACTPS database are necessary.
- understanding galvanizing bath chemistry and formation of intermetallic layers in galvanizing and galva-annealing process using conventional Zn bath and new AlMg bath.
- conditions for scrap remelting to maintain as low concentrations as possible of undesirable “tramp elements”
- understanding of oxidation (PO2-X diagram) and corrosion (EpH diagram) of steel in conjunction with FTOxid, FACTPS, FTmisc, and FTHelg database.
- etc.
As its name implies, the database is intended to allow calculations primarily for Fe-rich composition ranges, but since many of the assessed parameters, particularly for the binary and ternary sub-systems, provide reliable descriptions over all ranges of composition, calculations may sometimes be extended to higher concentrations of alloying components in Fe. Information on the possibility of calculating phase equilibria or thermodynamic properties for other composition ranges of multi-component alloys may be obtained by referring to the list of systems and phases for which assessed parameters are available (click on List FSSTEL). This will allow the user to determine whether proposed calculations for a particular higher-order system will be based on a complete set of assessed binary and ternary parameters (at best) or a summation of binary parameters only (at worst). Clearly the latter case, or use of incompletely assessed data sets, can lead to incorrect or unreliable results.
In a binary system, if no assessed mixing parameters are available for a particular phase, the phase will be treated as ideal. Correspondingly, the properties of a ternary or higher-order phase will be calculated applying the appropriate models used in the database. This procedure may give useable results if the alloy compositions in question are close to a pure component or to a binary edge for which assessed data are available. However, results of calculations for other composition ranges should be treated with extreme caution.
Specific information on each alloy system can be obtained from the list of references supplied with the List FSstel system and phase listing.
A matrix of the FSstel binary systems that have been assessed can be displayed by selecting ‘Documentation’ on the main FactSage menu, then ‘FSstel’ in the list of databases, and then ‘assessments’.
As mentioned above, the database is intended to allow calculations primarily for Fe-rich composition ranges, although the assessed data are also reliable for higher concentrations of alloying components in a number of cases.
The database is generally valid for the temperature range of approximately 400oC to 1800oC, although for some steels containing high melting point metals, calculations are reliable to still higher temperatures.
In the assessments, the liquid phase has been described using the Modified Quasichemical Model (MQM) with various interpolation technique for ternary and high order systems. Some assessments based on a simple substitutional liquid solution model with the Redlich-Kister-Muggianu polynomial expression are also integrated with the MQM. All solid solutions are described using a sub-lattice model. In particular, the FCC(austenite), BCC(ferrite) and HCP phases contain carbon, nitrogen, boron and vacancies on interstitial sites.
The phase diagrams of all the binary, many ternary and a good number of multi-component sub-systems have been checked using FactSage.
To provide correct or more accurate calculations, the I or J option is automatically selected for several phases including LIQUID, FCC, BCC, B2_BCC and L12_FCC. Disabling the I or J option for these phases may result in incorrect results. As well, if necessary, the user must select the I or J option for other solution phases which potentially have miscibility gaps.
1. I.-H. Jung, S.A. Decterov and A.D. Pelton, "A Thermodynamic Model for Deoxidation Equilibria in Steel", Met. & Mat. Trans., 35B, 493-508 (2004).