Vacuum Oxygen Decarburization (VOD) Process

About the Vacuum Oxygen Decarburization (VOD) Process

One of the requirements of stainless steel production is the ability to lower the carbon content without compromising on the Cr yield. This can be achieved by refining the steel under a vacuum via the vacuum oxygen decarburization (VOD) process. This process involves the three stages schematically outlined below:

schematic-of-the-vacuum-oxygen-decarburization-process — A schematic showing the three stages of the vacuum oxygen decarburization process – oxygen blowing, degassing, and reduction. This process can be simulated using the Process Metallurgy Module in Thermo-Calc, as discussed in this application example.

About this Example

In this example we look at how the Process Metallurgy Module can be used to simulate the VOD process. The example is configured to reproduce the VOD process described in the publication by Ding et al. [R. Ding, B. Blanpain, P.T. Jones, P. Wollants, Met. Mater. Trans 31B (2000) 197-206]. The kinetic simulation excellently reproduces the temperature, the steel chemistry, and the slag chemistry as a function of time. The example can easily be modified and adapted for different chemistries and process parameters.

Simulated temperature evolution during the VOD Process, made using the Process Metallurgy Module in Thermo-Calc.

Simulated steel chemistry evolution as function of time during the VOD Process, made using the Process Metallurgy Module in Thermo-Calc. The right plot is zoomed in.

Simulated slag chemistry and total slag amount as a function of time during the VOD Process, made using the Process Metallurgy Module in Thermo-Calc.

How to Run the Calculation

To run this example, open Thermo-Calc and navigate to the Help menu → Example Files… → Process Metallurgy. This example includes one calculation file:

PMET_07_Vacuum_Oxygen_Decarburization_Kinetics: requires a full license for Thermo-Calc 2021a or newer, the Metal Oxide Solutions Database TCOX10 or newer, and a license for the Process Metallurgy Module.

This example includes a PDF with in-depth explanations of all the calculations and interpretation of the results:

Read the Full Example

A similar example is included with installations of our SDKs TC-Python and TC-Toolbox for MATLAB®. The examples are installed locally in the SDK in the TC-Python or TC-Toolbox folders, and the full file path location is based on your OS. These examples are not directly accessible from the Thermo-Calc menu. See Thermo-Calc Installation Guides sections “Installation Default Directory” for the path to the applicable folder location for your OS.

In TC-Python: pyex_PMET_05_VOD_process_simulation.py
In TC-Toolbox for MATLAB®: matex_PMET_05_VOD_process_simulation.m

Additional Examples Using the Process Metallurgy Module

The Process Metallurgy Module can be used to investigate the entire steelmaking process, from scrap to fully refined steel. The examples below investigate other steps in the steelmaking process:

Application Example