Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
COMPARATIVE STUDY OF THE RESIDUAL STRESS INDUCED BY LASER SURFACE HARDENING OF AISI 1020 AND AISI 4130 STEELS
Submission Author:
Olga Liskevych , ES
Co-Authors:
Ana Sofia Andreão, Gabriela Rocha Profilo, SHEILA DE CARVALHO, Olga Liskevych
Presenter: SHEILA DE CARVALHO
doi://10.26678/ABCM.COBEM2023.COB2023-0701
Abstract
Laser hardening is an advantageous option among the variety of surface treatments of materials due to its flexibility, accuracy, good control of heat input in fusion and heat-affected zones, limited grain growth during heating and low distortion. Moreover, this procedure allows to increase the hardness of the surface region of the treated material without compromising the ductile properties of the substrate. As a consequence of temperature gradients and microstructural changes during heating and cooling cycles in hardened materials, residual stress can develop influencing resulting material properties and service exploitation. The purpose of this work was to investigate changes in the residual stress state after surface laser hardening of AISI 1020 and AISI 4130 steels, as well as its consequences for the properties of the aforementioned materials. To accomplish this objective, the magnitude and nature of the residual longitudinal and transversal stresses in the reference and laser processed samples were measured using the ESPI-based hole-drilling method. Afterwards, the local residual stress distribution was compared to the phase transformation occurred during hardening and microhardness of the processed areas. The results obtained in this study show that the materials exhibit different performances when subjected to laser hardening treatment under identical process conditions. Both materials showed martensite formation in the surface area, but only the AISI 4130 steel sample exhibited compressive stress induced during the hardening process. Meanwhile, tensile stress induction was observed in the AISI 1020 steel sample throughout the analyzed depth. The same effect was reported for both longitudinal and transversal components. Regarding the microhardness results, the AISI 1020 steel showed an increase of almost 87% when superficially hardened, while the AISI 4130 steel presented only an increase of approximately 61%. Therefore, in accordance with the results of this study, it was possible to conclude that despite the same process parameters during the treatment, the AISI 4130 steel presents a more effective application of laser surface hardening when compared to the AISI 1020 sample.
Keywords
laser hardening, residual stress, AISI 1020, aisi 4130, Microhardness
