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
  • Solute redistribution during solidification
  • Analysing the equilibrium of gas mixtures for heat-treatment
  • Interaction with environment, e.g. carburisation, oxidation, etc.
  • Selecting optimum temperatures for heat-treatment
  • Homogenisation 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.

Databases that are relevant for application to this class of material:

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.
TCFE9: TCS Steels/Fe-alloy database, v9 >>

SLAG is a thermodynamic database that covers a liquid slag phase (containing oxide/silicate/sulfide/fluoride species), as well as various oxide, silicate, sulfide and fluoride solid phases, and that allows for calculation on slags as well as equilibrium between liquid metal and slags.
SLAG4: TCS Fe-containing slag database, v4 >>

TCOX6 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.
TCOX7: TCS Metal Oxide Solutions Database, v7 >>

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).
MOBFE4: TCS Steel and FE-database, v4 >>