Por: Rennáh Francisco Figueiredo Gonçalves (Universidade Federal do rio grande do norte), Flavio José Saraiva Rodrigues (ArcelorMittal Tubarão), Jetson Lemos Ferreira (ArcelorMittal Tubarão), Adilson José de Oliveira (UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE), Anderson Clayton Alves de Melo (UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE), Fábio José Pinheiro Sousa (UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE), Nicolau Apoena Castro (UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE)
Resumo:
Advanced High Strength Steels (AHSS) have been applied in the manufacturing of automotive parts. These steels grades have a combination of a ferritic matrix, with high ductility; and a second constituent dispersed in the matrix (which can be martensite, bainite or a combination of both), which presents high hardness, making them more sensitive to edge damage. Defects such as nucleation and crack propagation from the cut edges may occur. Therefore, the objective of this research is to design, manufacture and test a experimental bench in order to evaluate cryogenic punching of the cold rolled DP780 steel sheet, with a thickness of 0.65 mm. Punching cutting at cryogenic temperatures is seen as an alternative for reducing the level of work hardening in the material, having the potential to produce parts with better cutting quality, as well as greater flange stretching capacity. The present study provided the development of a device for application of liquid nitrogen (LN2) on the sample, with the temperature control, and evaluated the work hardening distribution, using the EBSD technique, along the cut edges at ambient and cryogenic temperatures.
