Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
The influence of specimen surface roughness on tensile testing results
Submission Author:
Monica Beltrami , PR
Co-Authors:
Melissa Kikuchi, Rogerio Sucaria, Gismar Souza, Monica Beltrami
Presenter: Rogerio Sucaria
doi://10.26678/ABCM.COBEM2017.COB17-1942
Abstract
The tensile testing is performed to predict the behavior of a material under a uniaxial tension load. Many factors can affect the tensile test results, such as the specimen preparation. Therefore, the surface of the specimen, especially such gauge length, should be free from scratches or other damage that can act as stress raisers and cause early failure. Accordingly, the aim of this paper is to study the influence of the specimen surface roughness in tensile test results, using the ABNT/SAE 1020 steel. The specimens were manufactured in the CNC machine in accordance with ASTM E8 and ISO 6892-1, with five different speed rotations 1500, 2000, 2500, 3000 and 3500 rpm. The roughness of the specimens was evaluated by the Ra, Rq and Rz parameters. However, the Ra outcomes were taken as the main response of roughness. The tensile test results were assessed by observing the stress-strain curve behavior, and the tensile strength and percent elongation values. The Ra parameter results for the adopted rotation range varied within 1.134 µm to 1.967 µm and their smallest values were obtained with a 3000-rpm rotation. In contrast to the observed in the pre-tests realized by conventional machining, there was a small variation of the Ra roughness, between the best and the worst specimens ‘surface finish conditions, which was not sufficient to affect the tensile strength. The tensile strength variations were small and close to the expected value for the ABNT/SAE 1020 steel.
Keywords
Surface finish, Roughness parameters, Tensile testing, ABNT/SAE 1020 steel
