Characterization of the topography generated by low plasticity burnishing using advanced techniques

• Published in: Surface & coatings technology Vol. 448; p. 128891
• Main Authors: Oliveira, Diogo Azevedo de, Martins, Augusto Moura, Magalhães, Frederico de Castro, Abrão, Alexandre Mendes
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.10.2022
• Subjects: Burnishing; Dynamic analysis; Fatigue analysis; Stainless steel; Surface roughness; Texture; Burnishing; Surface roughness; Fatigue analysis; Texture; Dynamic analysis; Stainless steel
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2022.128891

This work investigates the surface topography of AISI 304 austenitic stainless steel after low plasticity burnishing through the evaluation of the average surface roughness (Ra), surface texture direction, areal power spectral density (APSD), scale-sensitive fractal analysis and continuous wavelet transform (CWT). The reason for adopting these approaches resides in the fact that traditional amplitude profile parameters neglect dynamic aspects of the process and geometric features of the burnished surface. The direction, periodicity and anisotropy of the surface texture were influenced by number of passes and burnishing speed and, in general, less severe plastic strain conditions tended to produce surfaces with strongly anisotropic characteristics, preferred direction of motifs, with power spectrum indicating a well-defined spatial frequency of peaks, lower fractal complexity and uniform profile distribution. The increase in surface strain severity produced surfaces with more diffuse directional characteristics, which tended to present surface isotropy, higher spatial frequency dispersion of the peaks and higher fractal complexity. Furthermore, the transition from an anisotropic to an isotropic surface can occur without changes in the average surface roughness. The continuous wavelet transforms analysis indicated a dynamic variation on the surface plastic strain when burnishing. The intermediary burnishing speed induced a strong disturbance with loss of periodicity of the roughness profile, resulting in a remarkable influence on the roughness profile in small scales. The increase in number of passes elevated the plastic strain severity, affecting the surface macrogeometric profile. The isotropic surface promoted a less severe stress concentration, reducing the tensile stresses and retarding crack nucleation, thus increasing the fatigue considerably. •Surfaces with isotropic or anisotropic characteristics can be produced depending on the burnishing parameters.•Burnishing parameters affect the directionality, spatial frequency and fractal characteristic of the roughness profile.•The characterization techniques are suitable to evaluate the dynamic behavior of the burnishing process.•The isotropic surface had a higher number of cycles to crack nucleation than the anisotropic surface, despite the same roughness.