Additive manufacturing innovations: microstructure optimisation for ultra-high silicon electrical steel components

The main objective of this work is to fabricate high‑silicon electrical steel with an optimized microstructure for magnetic applications through additive manufacturing (AM) routes. Traditional thermomechanical manufacturing routes, such as hot and cold rolling operations, have struggled to produce non-oriented electrical steel (NGOES) components with more than 3.4 wt% Si contents. However, the need for efficiency improvements requires an increase in silicon contents up to 6.5 wt%, leading to compromised magnetic and mechanical properties through conventional manufacturing techniques resulting in technical limitations on the production of these alloys. AM is a promising manufacturing approach that can address this challenge through near-net-shape fabrication. Optimisation process conditions in AM provide flexibility and enable better, more precise control over the microstructure. This study explores the microstructure and texture development of FeSi 6.5 wt% NGOES fabricated via laser metal deposition (LMD), with a build plate preheated to 200 °C to mitigate thermal stresses and cracking. The influence of process parameters on microstructure has been investigated. Process parameters, including laser power (400–500 W) and scanning speed, were adjusted to modify melt pool geometry, with energy density ranging from 74 J/mm2 upward. Microstructure and texture were characterized using electron back-scatter diffraction (EBSD), revealing elongated grains with a strong 〈001〉//BD fibre texture. Higher laser energy density enhances cube texture, improving magnetic properties, while increased laser power increases grain size, favouring <001> texture. These findings highlight the critical roles of energy density, laser power, and build plate temperature in tailoring NGOES microstructure and texture for enhanced performance.