Banca de DEFESA: JANDIR CAETANO FERREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JANDIR CAETANO FERREIRA
DATE: 03/05/2024
TIME: 14:00
LOCAL: Auditório - Sala 101
TITLE:

STUDY OF THE INFLUENCE OF THE GUILLOTINE CUTTING PROCESS ON THE MAGNETIC AND MECHANICAL PROPERTIES OF NGO N030-16 SILICON STEEL SHEETS

KEY WORDS:

Grain-oriented electrical steels; non-oriented grain; magnetic losses; Cutting conditions; Heat treatment; Punching.

PAGES: 89
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SPECIALTY: Propriedades Físicas dos Metais e Ligas
SUMMARY:

Non-oriented grain electrical steels (NGO) are essential components of the core in electric or hybrid vehicle motors, which are part of a rapidly growing market worth millions of dollars annually. For motor applications, this steel undergoes a cutting process that can be carried out by guillotine shearing, potentially inducing structural alterations due to mechanical cutting. Improper adjustment of the cutting clearance between the guillotine blades increases the steel's magnetic losses, reduces its electromagnetic efficiency, and raises the costs associated with its application. In order to study the influence of the cutting clearance and the number of cuts on magnetic losses, strips of 30 mm width of a NGO were cut into two and four parts, resulting in strips with widths of 15 mm and 7.5 mm, respectively. An industrial guillotine was employed for this mechanical intervention, applying clearances of 0.01 mm and 0.03 mm. The cutting regions of the blades were analyzed by scanning electron microscopy (SEM), and all samples also underwent detailed evaluation of their magnetic properties. SEM analysis revealed that cutting induces plastic deformation in the region near the edge, extending up to 120 microns into the material, with greater extension observed with larger clearances. The results of the magnetic analyses indicated that total magnetic losses were higher in all induction and frequency scenarios when a clearance of 0.03 mm was employed compared to 0.01 mm. When comparing the evolution of losses with the number of cuts, at 1 T and 400 Hz, it was observed that the blade segmented into four parts of 7.5 mm exhibited 45% more losses than the unsegmented blade (30 mm), while at the same polarization and 60 Hz, there was a 39% difference. Thus, higher frequencies, more blade segmentations, and larger cutting clearances resulted in higher losses. Parameters such as coercivity, remanence, and relative permeability were also considerably affected. Through analysis of the loss components, it was observed that hysteresis loss was significantly more affected than eddy current and excess losses. Therefore, this study demonstrates the fundamental role of plastic deformations on the magnetic properties of the material, indicating that cutting induces changes in the material's crystalline structure, thereby compromising the magnetic coupling between the magnetically active atoms in that region, which reduces the performance of electrical steels.

COMMITTEE MEMBERS:
Presidente - DANIEL LEANDRO ROCCO
Interno - VALMIR DIAS LUIZ
Externo ao Programa - ALMIR SILVA NETO
Externo à Instituição - JOAO TRAJANO DA SILVA NETO - IFMG