Roughness and Hardness of 60/40 Cu-Zn Alloy
— The functional performance of machined components, often, depends on surface topography, hardness, nature of stress and strain induced on the surface, etc. Invariably, surfaces of metallic components obtained by turning, milling, etc., consist of irregularities such as machining marks are responsible for the above. Surface finishing/coating processes used to produce improved surface quality/textures are classified as chip-removal and chip-less processes. Burnishing is chip-less cold working process carried out to improve surface finish, hardness and resistance to fatigue and corrosion; not obtainable by other surface coating and surface treatment processes. It is a very simple, but effective method which improves surface characteristics and is reported to introduce compressive stresses. micro-irregularities start moving in the direction of the newly formed surface. The grain structure is condensed, producing a smoother and harder surface with superior load-carrying and wear-resistant capabilities. 2 + 0.0525X 4 + 0.0125X 1 X 4 − 0.02X X 4 − 0.0375X 3 X 4 Hv=160.625 − 2.37 5X 1 + 5.125X 2 + 1.875X 3 + 4.375X 4 − 1.625X 1 X 4 + 4.375X 2 X 4 − 2.375X 3 X 4 High surface microhardness (175H V ) was obtained at 400rpm, 2passes, 0.05mm/rev and 15kgf., and high surface finish (0.20µm) was achieved at 30kgf, 0.1mm/rev, 112rpm and single pass. In other words, surface finish improved by 350% and microhardness improved by 21% compared to as machined conditions.
A study on the surface characteristics of burnished components
Abstract Burnishing is a plastic deformation process in which the asperities of a machined surface are depressed to give a smooth and workhardened surface. In this paper, the development of a roller type burnishing tool is reported together with some experimental results concerning roughness and microhardness of surfaces of alloyed aluminium components.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.