Banca de DEFESA: HENRIQUE TOMÉ BARBOSA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : HENRIQUE TOMÉ BARBOSA
DATE: 15/09/2023
TIME: 07:30
LOCAL: meet.google.com/tdb-togb-xme
TITLE:

Study of the microstructure of DP780 steel punched under room and cryogenic temperatures.

KEY WORDS:

DP780, Cutting Edge, Punch-cutting Refrigeration, EBSD.

PAGES: 75
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUMMARY:

Dual-phase steels (DP) are advanced high-strength steels (AHSS) used in construction of automotive body parts due to their high strength, formability and ability to absorb energy when deformed. They gained great importance since the Paris Agreement (2016), as their use, in place of conventional steels, makes vehicles lighter and less polluting. To constitute these automotive parts, the dual-phase steels undergo stamping processes, in which they are cut, pressed and folded, in order to compose the final shape of the desired part. During these processes, the quality of the cutting edge of these steels is a very important factor, as an edge with more and greater heterogeneity and defects can lead to failure of the part even during its manufacture. A more homogeneous cutting edge, with less voids and microcracks is necessary for the good formability of these materials. Aiming to present a method to improve the quality of the cutting edges of DP780 steel, the present work carried out a qualitative and quantitative study of the microstructures of cutting edges of this steel cut by punching at cryogenic and ambient temperatures and compared them, in order to verify their quality and homogeneity, as well as the amount of deformation. The analysis of the microstructures was performed using the Electron Backscatter Diffraction (EBSD) technique using a scanning electron microscope (SEM).It was observed that the localized refrigeration by liquid vapor is effective for the induction of brittle fracture in the DP780 dual-phase steel, extending the fractured region and decreasing the sheared area in the cut edges, diminishing plastic deformation in the surface and internal microstructure of the edge. Qualitative results showed the ability of this method to reduce plastic deformation on DP780 cutting edges by up to 37% when performed at cryogenic temperature (≤ -150 ^oC) and speed of 725 mm/s.

COMMITTEE MEMBERS:
Presidente - 2266607 - FABIO JOSE PINHEIRO SOUSA
Interna - 1481705 - SALETE MARTINS ALVES
Externo ao Programa - 1938946 - NICOLAU APOENA CASTRO - UFRNExterno à Instituição - JETSON LEMOS FERREIRA