Optimizing Induction Heating of WNiCo Billets Processed via Intensive Plastic Deformation

Lenka Kunčická,Rudolf Petrmichl,Adéla Macháčková,Zuzana Klečková,Martin Marek

doi:10.3390/app10228125

Lenka Kunčická, Rudolf Petrmichl + Show 3 more

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https://doi.org/10.3390/app10228125

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Abstract

The aim of the work is to optimize the induction heating regime and propose a suitable deformation temperature for a pre-sintered powder-based tungsten heavy alloy workpiece subsequently processed via rotary swaging. The heating regime is designed with the help of numerical analyses and subsequent experiments. The first part of the study focuses on the theoretic background of the induction heating and comprises the development of a reliable induction heating model via performing electromagnetic simulations in two individual computational software packages (for verification). The second part of the study then involves the optimization of the heating regime using the designed numerical model. Last but not least, the predicted results are compared to the experimentally acquired results, and the optimized heating regime, applicable before experimental rotary swaging of the WNiCo workpiece, is proposed. The results of the microstructure analyses of the workpiece heated to the selected optimum deformation temperature of 900 °C showed that the designed induction heating procedure provided sufficient heating of the bulk of the workpiece (contrary to the lower swaging temperature), as the swaged microstructure featured well-deformed tungsten agglomerates. Furthermore, the analyses documented the high-quality oxidation-free surface of the particular workpiece (contrary to the higher swaging temperature).

Highlights

Within the last five decades, induction heating has become a favorable method for the heating of metallic workpieces throughout various industrial branches [1]
Having verified the Forge NxT 3D model by comparing the results of the electromagnetic computations with the result acquired from the ANSYS Maxwell 2D model, the induction heating was simulated in 3D space only
The observed differences between the results can primarily be attributed to the fact that the Forge NxT model calculates in 3D space, whereas the ANSYS-Maxwell model works in 2D space

Summary

Introduction

Within the last five decades, induction heating has become a favorable method for the heating of metallic workpieces throughout various industrial branches (e.g., transportation, aerospace, marine industry, etc.) [1]. It is mostly used to (pre)heat ferromagnetic materials, such as steel [2], since they intensify the magnetic field and induce the induction effect already at relatively low frequencies. Sci. 2020, 10, 8125 such as the melting of metals [3], the annealing and quenching of metallic components and surfaces [4], the preheating of workpieces intended for subsequent deformation processing [5], surface heating prior to specific surface treatments [6], and more. Unsuitable settings of the heating process result in insufficient and/or inhomogeneous heating of the workpiece, and increase the possibility of the occurrence of microstructure inhomogeneities and defects within the material (e.g., local melting or overheating resulting in undesired abnormal grain growth), as well as the development of an unfavorable stress state, which can result in the occurrence of residual stress during subsequent processing [7,8,9]

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