Simulation of induction heating of steel billets for forging

Induction is becoming an increasingly popular choice for heating steel billets prior to forging, due to its ability to create high heat intensity quickly and within a billet, which leads to low process-cycle time (high productivity) with repeatable high quality, occupying minimal space on the shop floor. It is more energy-efficient and inherently more environmentally friendly than most other heat sources for steel billets.

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In this article we'd like to demonstrate a simulation example on how to optimise a progressive induction heating system for a steel billet using CENOS Platform - a 3D simulation software which is focused specifically on induction heating and uses open source components and algorithms, making it affordable for small and medium companies.

CENOS platform is capable of simulating various types of induction heating for forging. It is possible to simulate both static heating and progressive heating where the billet is moved through the coil with constant velocity.

The coil design is also of no limitations - single coil, multi-coil are possible to simulate. Besides the coil it is also possible to simulate any material and frequency.

The functional performance of the software

CENOS is a finite element method based computer-aided engineering desktop software for 2D and 3D physical process simulation & computational modelling of induction heating, induction hardening, brazing, annealing and tempering of steel, aluminium, copper and other materials.

It was designed to be as simple as possible to understand and use even for beginners.

The simulation process consists of three steps:

  • Choose the workpiece geometry (from built-in templates or create your own CAD file)

  • Define induction heating parameters (frequency, voltage, time, etc.)

  • Run 2D or 3D simulation of your choice

At the end, results like temperature and magnetic field are displayed in 3D renderings, plots and more. Apparent power, induced heat and inductance are logged into an Excel file.

3D Simulation example - comparison of two heating systems

Here, the progressive heating of the billet is simulated, with two systems under consideration - two stage and three stage systems.

The target for the simulation was to reach 1200 ℃ ± 50 ℃.

To check both systems, user had to create setup for both of them, set physical parameters (material properties, frequency, current etc.) and start the simulation.

After the simulation is done, user have access to different output variables:

  • Temperature distribution

  • Current density and Joule heat distribution

  • Magnetic field lines

  • Total, reactive and apparent power

  • Inductance of the coil

  • Coil current, voltage

  • etc.

In our example of billet heating is possible to compare both cases and the output.

It is visible how a three stage system can decrease the power consumption and increase the production rate for this specific case.

It is also possible to plot the distribution of temperature, Joule heat, magnetic field etc. A resulting temperature distribution in the billet across the radius is shown in Figure 1. As can be seen, better temperature homogeneity is obtained in the three stage system.