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Process Metallurgy

Thermo-Calc can be used to model the key variables of a steelmaking process to develop recipes for new grades or novel processing routes.

Applications to Process Metallurgy

Producers face the daily challenge of changing compositions and costs of raw materials, new regulations on emissions, the fluctuating cost of energy, and modified specifications from their customers. Using Thermo-Calc, the key variables of a process can be simulated to balance quality, energy consumption, CO2 emissions, and total process cost. Additionally, it can be used to develop recipes for new grades or novel processing routes such as direct reduction by hydrogen instead of coke or natural gas.

For slag/metal reactions, Thermo-Calc can be used to calculate the following as a function of temperature and composition:

  • Slag/metal equilibrium and final steel chemistry
  • Desulfurization, dephosphorization, decarburization
  • Partition coefficients between the slag and liquid metal
  • Slag characteristics, such as slag basicity or sulfur capacity, as well as composition in components, such as Al2O3 or SiO2
  • Fraction of liquid and solid in the slag
  • Temperature evolution due to oxidation (adiabatic calculations)
  • Relevant heat, mass, and thermodynamic calculations for the extraction of base metals

Application Examples

Thermo-Calc has many applications to process metallurgy. Below is one such example.

Slag Metal Reaction Kinetics During Refining

Reactions occurring during steelmaking and refining do not reach thermodynamic equilibrium due to kinetic limitations. To take these into consideration, an effective equilibrium reaction zone (EERZ) model has been implemented into Thermo-Calc. This model assumes local equilibrium at phase interfaces, such as the interface between liquid steel and slag, but allows for the fact that thermal and composition gradients in the phases are present. The kinetics of the reactions are therefore limited by the mass and heat transfer to and from the reaction interface.

This figure, which was produced using the Process Metallurgy Module in Thermo-Calc, shows a comparison of predicted inclusion composition with the experimental data for a ladle refining process of a Ti-stabilized ultra-low carbon steel published by Graham and Irons.

A plot showing inclusion composition vs time for a Ti-stabilized ultra low carbon steel during refining.

Process Metallurgy Module for Steel and Slag

The Process Metallurgy Module is an Add-On Module for Thermo-Calc that makes it easy to set up calculations for steel and slag interactions. The Module includes a kinetic model that simulates the evolution of the steel, slag, and inclusion compositions as a function of time based on the actual steelmaking process. Process parameters such as blowing of gases into the steel, heating by electric arc, and slag additions can be considered.

Learn more about Applications to Process Metallurgy

Several examples showing how the Process Metallurgy Module can be used throughout the steelmaking process.


Simulating the Steelmaking and -Refining Process using Thermo-Calc’s Process Metallurgy Module

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

A Kinetic and Thermodynamic Description of the Steel Making Process using Thermo-Calc and the CALPHAD Database TCOX
in Proceedings of METEC & 3rd ESTAD 2019, European Steel Technology and Application Days: Düsseldorf, Germany, 2019.

The Application of an Effective Equilibrium Reaction Zone Model Based on CALPHAD Thermodynamics to Steel Making

A collection of videos demonstrating the capabilities of the Process Metallurgy Module.

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