Banca de DEFESA: ANDEILSON BERNARDO BEZERRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANDEILSON BERNARDO BEZERRA
DATE: 16/12/2022
TIME: 14:00
LOCAL: videoconferência pelo Google Meet (https://meet.google.com/nec-qzah-ggk)
TITLE:

Development of an experimental bench for cryogenic punching of thin steel sheets applied for automotive structures

KEY WORDS:

ULC, AHSS, punching, cryogenics, edge stretching

PAGES: 94
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUBÁREA: Processos de Fabricação
SPECIALTY: Processos de Fabricação, Seleção Econômica
SUMMARY:

The reduction of vehicles mass, without a significant impact on their resistance or users’ safety, is a decisive factor for the viability of less-polluting vehicles and mitigation of environmental effects. The application of increasingly thinner steel sheets in the automotive structure has been one of the ways to achieve this objective. In this sense, Ultra Low Carbon (ULC) steels and Advanced High Strength Steels (AHSS) have been widely applied in manufacturing automotive bodies' structural parts. In particular, AHSS combines a ferritic matrix with high ductility; and a second high-hardness constituent (which can be martensite, bainite, or a combination of both) dispersed in the matrix. This microstructural characteristic allows the processing of AHSS by forming and stamping. However, defects such as cracks, nucleated from the cut edges, can occur due to the presence of this second constituent. An alternative to minimize crack nucleation is to carry out the stamping process at cryogenic temperatures. The hypothesis is that if the process is carried out at low temperatures, there will be a change in the plastic deformation mechanism from shear to deformation by mechanical twinning and cleavage. Therefore, this research aims to design, manufacture and test an experimental bench adapted to a shaper machine to evaluate cryogenic punching in two steel sheets applied for automotive structures. Tests were carried out with Ultra Low Carbon (IF) and AHSS (DP780) steels, with a thickness of 0.65 mm, and results showed the process feasibility at cryogenic temperatures. The most significant changes were the reduction of plastic deformation regions and the increase of the fracture zone in the samples processed at temperature below -150 °C when compared with those tested at room temperature.

COMMITTEE MEMBERS:
Presidente - 1792669 - ADILSON JOSÉ DE OLIVEIRA
Interno - 1545410 - ANDERSON CLAYTON ALVES DE MELO
Interno - 1938946 - NICOLAU APOENA CASTRO
Externo à Instituição - JETSON LEMOS FERREIRA