Browsing by Subject "surface layer"

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Access status: Open Access ,
Fabrication of surface layer enriched with zinc on AlSi17 aluminium cast alloy by hot-dip galvanizing
(AGH University of Science and Technology Press, 2019) Bucki, Tomasz; Bolibruchová, Dana
The paper deals with the fabrication of the surface layer enriched with Zn on AlSi17 aluminium alloy to modify the microstructure and surface properties of the alloy. The continuous surface layer was fabricated on the AlSi17 substrate by the hot-dip galvanizing of AlSi17 for 15min in a Zn bath heated to 450°C. The thickness of the layer was about 100 ?m. The layer was characterised by a multi-component microstructure containing the regions of a solid solution of Al in Zn and dendrites of a eutectoid composed of a solid solution of Al in Zn and a solid solution of Zn in Al. In the layer, fine particles of Si with a regular shape were distributed. The results indicated that these Si particles formed by the action of Zn on the eutectic Si precipitations in the AlSi17 substrate. In the microstructure, large primary Si crystals and multi-phase precipitations, originating from the substrate, were also observed. The surface layer had much higher microhardness than the AlSi17 substrate. The results showed that hot-dip galvanizing can be used to modify the microstructure and properties of the surface layer of AlSi17. The study indicates the possibility of conducting further research on the fabrication of joints between AlSi17 and other metallic materials using a Zn interlayer fabricated by hot-dip galvanizing.
Access status: Open Access ,
Statistical evaluation of the measurement of residual stresses in the surface layer of CP1000 steel sheets using the magnetic Barkhausen noise and X-ray methods
(Wydawnictwa AGH, 2025) Kliś, Janusz; Nawrat, Rafał; Olbrych, Jakub; Węgrzyniak, Michał; Szydło, Damian; Toczek, Grzegorz; Sozańska-Jędrasik, Liwia
The paper presents an analysis of the possibility of measuring the residual stresses of metal sheets with the application of the so-called Barkhausen effect. The aim of the research was to compare the residual stress levels measured by two methods of multiphase steel sheets (ferritic-martensitic-bainitic) in grade HCT980C after flattening on a roller leveller in industrial conditions. The measurements were carried out using two methods: the Barkhausen effect method and the X-ray method. The paper describes in detail the methodology used for testing the measurement of residual stresses. The residual stress testing of sheets made of the CP1000 steel group was supplemented with tests of chemical composition, microstructure and mechanical properties (Re, Rm, A80, HRC hardness). In the analysis of the research results, elements of statistics were also used, in the form of ordinary correlation. The research results showed that in the case of sheets after flattening on a roller leveller in industrial conditions, it is possible to replace the commonly used and recognized, but labour-intensive X-ray method, with a simple, innovative and cheap to use method using the Barkhausen effect. Stress measurement using the Barkhausen effect has already been found to be applicable in the diagnostics of tracking changes in the stress value in the material in industrial pipelines, where access to the other measurement methods is difficult or even impossible. Currently, the measurement of stress in sheets by the magnetic method is introduced on the transverse cutting line when cutting the sheet metal from coils to metal sheets. The measurement of stresses in the production of steel sheets is important because the difference in stress between the top and bottom sides of the sheet has a significant effect on the flatness of manufactured metal sheets.