Estudo das tensões residuais geradas na usinagem por fresamento e retificação de aço superduplex

Abstract

Superduplex steels are used in equipment for the naval and offshore industries due to their greater mechanical strength and high corrosion resistance compared to other stainless steels. Being a difficult-to-machine material, the manufacture of machined components from these steels represents a challenge for the metalworking industry. During machining, the heat production associated with high deformations in the cutting zone generates residual stresses that can be of high magnitudes and, depending on their nature, impact the service life of the machined parts. In this work, the residual stresses generated during machining by end milling and surface grinding of superduplex steel samples were analyzed. The residual stresses were measured by X-ray diffraction, by the sen²ψ method using Crκα radiation. The results show that, in the end milling process with different parameters, the residual stresses generated were predominantly compressive, and with the use of higher cutting speeds and lower feeds, they reached an average of ‒670 MPa. The grinding process generated tensile residual stresses and the higher feed resulted in an increase in these stresses (500 MPa), which could be detrimental to the service life of a component machined in this way. Analyses of the machining force and roughness complemented the present study.