The article will be focused on monitoring the influence of the structure on the fatigue properties of aluminium alloys for the casting of type Al-Mg, especially EN AC 51200 and EN AC 51500. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable, only in the case of the concentration of magnesium are these alloys significantly different. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces.

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The Structure of the Aluminium Alloy and Its Influence on the Fatigue Properties

The article will be focused on monitoring the influence of the structure on the fatigue properties of Al-Mg cast alloy. As an experimental material were used aluminium alloys EN AC 51200 and EN AC 51500, supplied in a cast state without a heat treatment, which were produced by the continuous casting method. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces. This study has been supported by the Scientific Grant Agency of the Ministry of Education of the Slovak Republic VEGA 01/0683/15 and European Union project ITMS 26220220154.​

https://www.mmsconf.eu/index.php/mms/mms2017/paper/download/15/154

The influence of the structure on the fatigue properties of aluminium alloys for the casting.

Lean duplex stainless steels were developed for use in environments where high strength and corrosion resistance are required. Duplex stainless steels offer a cost-effective solution with high strength and corrosion resistance. Due to high chromium content and a balanced composition, 1.4362 ferritic-austenitic stainless steel possesses excellent corrosion resistance in acidic environments. General corrosion problems in duplex stainless steels at 475°C have been widely researched. Steels are most degraded at 475°C, but corrosion can still occur at both lower and higher temperatures. Corrosion resistance is influenced by chromium content and microstructural morphology. The percentage of each phase and its properties are determined by composition, technological processing and heat treatments. Machining and fabrication practices, such as welding, are also vital for performance. The objective of this study was to determine the effects of 30-minute isothermal heat treatments at 535°C and exposure time on relative mass loss and roughness parameters of 1.4362 lean duplex stainless steel. The influence of boiling nitric acid on the corrosion resistance of steel was investigated based on mass loss and roughness parameters. Corrosion properties and roughness of 1.4362 alloys are discussed in this paper.

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Corrosion Resistance of 1.4362 Steel in Boiling 65% Nitric Acid

Change of Internal Friction on Magnesium Alloy with 5.48% Al and 0.813% Zn ☆

All technical metals used not only in agriculture are subject to degradation processes, there are distinguished two main types: mechanical abrasion and physical-chemical degradation (corrosion). In order to lower abrasion of a machine part, it is necessary to use appropriate technical materials as well as an appropriate heat treatment. To minimize losses caused by corrosion, an appropriate anticorrosion system has to be used. This paper evaluates corrosion and mechanical resistance of waterborne acrylate anticorrosion systems sold on the Czech market. These paints were applied by an air flow technology. Mechanical characteristics of the applied coating were evaluated according to the CSN EN ISO 4624 (pull-off test for adhesion), CSN EN ISO 2409 (cross-cut test) and CSN EN ISO 1520 (cupping test). As used anticorrosion systems were applied also on zinc-dipped coating, this duplex system was also subject to the mentioned tests. Corrosion resistance of the tested anticorrosion systems was analysed in the salt-spray environment (CSN EN ISO 9227). Based on the results of the individual tests, there can be characterised adhesion, flexibility and mechanical resistance of waterborne anticorrosion systems as well as a further application on zinc layers. Corrosion tests analyse the process and visual appearance of corrosion attack.

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Usage of Waterborne Acrylate Anticorrosion Systems for Ecological Environment

AISI 316Ti is Cr-Ni-Mo austenitic stainless steel stabilized by Ti, recommended for construction of various industrial and medicine devices. In spite of its high Pitting Equivalent Resistance Number (PREN=23.688) it underlies local corrosion namely pitting in aggressive chloride environment. Appearance and extent of AISI 316Ti corrosion damage in a particular chloride solution depends strongly on temperature and surface treatment. One part of tested specimens is surface untreated the second part is treated by nitric acid passivation. Specimens are immersed for 24 hours at the temperatures of 30, 50 and 80 °C in 0.3M FeCl3 solution to induce pitting. Pitting corrosion morphology (shape and size of corrosion pits) is observed viewed from above and in profile as well, by optical metallographic microscope and scanning electrone microscopy SEM. Shape and size of corrosion pits is compared in dependence on temperature and surface finish of specimens.

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Juraj Belan

Papers

Variability of Local Corrosion Attack Morphology of AISI 316Ti Stainless Steel in Aggressive Chloride Environment