Steels and Iron-based alloys

This important class of materials has been studied in detail by the CALPHAD community. As a consequence, there exist very extensive databases that allow for accurate calculations of multicomponent phase equilibrium in these alloys, but also their reaction with atmosphere, slags and other materials during processing or in service.

By using our products, a wide range of situations can be analysed, which are relevant for steel making and/or the use of steels and Fe-based alloys. Please note that the list below could be made much longer.

Examples of applications that can be studied are:

  • Influence from alloying elements on phase stability and solubility limits 
  • Controlling and designing slag systems 
  • Interaction between slag and liquid metal
  • Non-metallic inclusion engineering 
  • Slag-refractory interaction
  • Influence from external pressure on the solubility in liquid metal
  • Microsegregation during solidification | Example Calculation
  • Analyzing the equilibrium of gas mixtures for heat-treatment
  • Interaction with environment, e.g. carburization, oxidation, etc. 
  • Selecting optimum temperatures for heat-treatment 
  • Homogenization of as-cast alloys
  • Interdiffusion in compounds
  • Transformation kinetics, e.g. austenite -> ferrite, carbide dissolution, etc.
  • Evolution of precipitate size distribution 
  • And much more…

Many different properties can be extracted from either equilibrium or non-equilibrium calculations and a partial list is supplied below.

Examples of properties that can easily be calculated are:

  • Transformation temperatures, such as liquidus, solidus, A1, A3, etc.
  • Isothermal or vertical section phase diagrams
  • Amount and constitution of equilibrium phases
  • Driving forces
  • Thermochemical properties, such as enthalpy, heat capacity, specific heat, etc.
  • Thermophysical properties, such as volume, density and thermal expansion
  • Scheil-Gulliver non-equilibrium solidification paths
  • And much more…

The most sophisticated database for this class of alloys is without any question the Thermo-Calc Steels/Fe-alloy database (TCFE), but there are also other databases that may suite your specific needs.

APPLICATION EXAMPLE: Microsegregation during Solidification

See an example which uses Thermo-Calc together with the Add-on Diffusion Module (DICTRA) to investigate and predict microsegregation (solute redistribution) during solidification. The example includes a comprehensive analysis of the calculation and a calculation file which you can download and run in Thermo-Calc. 

See the Microsegregation during Solidification example »

Hardenability Design of Steel

Read an in-depth example which shows how the Steel Model Library in Thermo-Calc can be used to find the optimal compositions for an Fe-Mn-C steel to achieve high hardenability for the purpose of strength. The example includes calculation files, which can be downloaded and run if you have a license for Thermo-Calc and the relevant databases. 

See the Hardenability Design of Steel example» 

Steel Model Library

The Steel Model Library is a set of Property Models designed to help experts working in the steel industry to quickly and easily set up calculations using the Property Model Calculator.

The pre-built steel models currently include the Martensite FractionsMartensite Temperaturesand Pearlite Models. A bainite model will also soon be available.  

The Steel Model Library is available for free to all users who have, or upgrade to, the thermodynamic (TCFE10) and mobility (MOBFE5) steel databases plus have a valid Maintenance and Support Subscription. 

Learn more about the Steel Model Library » 

Process Metallurgy Module for Steel and Slag

The Process Metallurgy Module is a calculator within Thermo-Calc that makes it easy to set up calculations for steel and slag. 

The module is designed for application to steel-making and steel refining processes including converters, such as basic oxygen furnaces, electric arc furnaces, ladle furnace metallurgy and more.

Learn more at the Process Metallurgy Module »

WEBINAR: Steel Making and Steel Refining using Thermo-Calc and the TCOX9 Database

This in-depth webinar shows you how Thermo-Calc can be applied to steel-making and steel refining using the Process Metallurgy Module and the TCOX9 thermodynamic database for oxides and slags. The webinar walks you through several examples showing how Thermo-Calc can be used during the steel-making and steel refining process. 

Watch The Webinar


Relevant Databases:

TCFE is a thermodynamic database suitable for many different kinds of Fe-based alloys, e.g. stainless steels, high-speed steels, tool steels, HSLA steels, cast iron, corrosion-resistant high strength steels and also cemented carbides. This database can be used for alloy compositions, but also their interaction with atmospheres containing oxygen, nitrogen, carbon, hydrogen or mixtures thereof.
TCFE10: TCS Steels/Fe-alloy database, v10 >>

TCOX also contains a slag phase description (ionic liquid solution phase for metallic and oxide melts) that allows for calculations on slag systems, as well as their interaction with liquid steel. In addition, this database contains a sophisticated description of solid oxides that makes it ideal for analysing oxidation, ceramic or refractory systems.

TCOX10: TCS Metal Oxide Solutions Database, v10 Technical Information >>

MOBFE is a mobility database that is compatible with TCFE and can be used in conjunction to TCFE for simulations in the Diffusion Module (DICTRA) and/or the Precipitation Module (TC-PRISMA).
MOBFE5: TCS Steel and FE-database, v5 >>