|Michał Jesiotr, Michał Tarnowski, Beata Kucharska, Dawid Myszka, Tadeusz Wierzchoń|
The article presents a method of modification of ceramic mould surface on the boundary between lost-wax model - ceramics by using a layer of nickel on a disposable model made of a specified type of polymer e.g. polymethyl methacrylate (PMMA) and then applying the layers of a ceramic mould to such a model. Successive phases consist in removing the model from the ceramic shell so that the metallic layer remains in the mould. After annealing it will be possible to pour liquid metal of a specific melting point e.g. aluminium alloy, to a mould prepared in this way. This way it is possible to obtain a high quality casting surface, of certain roughness and lack of surface defects. The research hypothesis stated in the article is to design a metallic coating in a ceramic form to get better wettability with molten metal than when using conventional techniques of precision casting.
Keywords: nickel layers, precision casting, casting models, polymeric materials,
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Dawid Myszka, Tadeusz Cybula
The article attempts to compare the resistance of austempered ductile cast iron and S215 steel to dynamic loads. The samples were subject to research using the Taylor test methodology at different speeds of deformation, in order to determine the characteristics of the material (Fig. 1). There was a significant increase in hardness in the highly deformed areas, and changes in the microstructure indicating the strengthening of the material. It was determined that the studied properties are comparable in steel and in iron after heat treatment on the basis of assessment of dynamic yield limit and the strengthening coefficient. The results of both materials may be used to assess their suitability for the production of equipment operating under extreme load conditions.
Keywords: austempered ductile cast iron, dynamic deformation, strengthening, austenite,
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Ferdynand Romankiewicz, Remigiusz Romankiewicz
Studies on the modification of aluminum brass CuZn30Al3 have shown that the additives used in combination 0.01−0.02% boron and 0.025−0.05% titanium resulted in a favorable change in the structure of the tested alloy. As a result, there has been a significant increase in impact strength caused by changes in the character brass breakthrough. There has been an increase in the contribution of the ductile fracture.
Keywords: modification; structure; aluminium brass,
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Andrzej Drotlew, Małgorzata Garbiak, Jerzy Kubicki, Bogdan Piekarski, Paweł Siluk
The paper presents a procedure that allows a quantitative comparative assessment of the flexibility of different design solutions of guide grate cast. Guide grate is an essential component part in all types of technological equipment structures used for arranging and transporting charge in furnaces during heat treatment. It is an openwork and thin-walled construction element. Values of forces and stresses created in the proposed guide grates due to deformation are specified. On this basis, the most advantageous structure solutions are indicated.
Keywords: creep resistant austenitic cast steel, castings for heat treatment plants, grates,
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Artur Kudyba, Natalia Sobczak, Aleksandra Siewiorek, Marta Homa
The aim of this study was to determine the impact of technological factors (surface treatment and contact time) on the kinetics of wetting of nickel substrates by a liquid aluminum alloy. Wetting kinetics studies were carried out in vacuum at 700°C with a sessile drop method, using the CP (capillary purification) test procedure. The CP procedure involves heating separately a pair of test materials, while a drop of metal is cleaned from the oxide coating by pressing the melt through the graphite drip. Tests were carried out on the industrial alloy 226D (Al base, Si 10.75%, Cu 3.3%, Fe 0.75%, Mn 0.215%, Mg 0.2%, Zn 0.23%), and pellets of freshly polished nickel (Ni 99.8%) and nickel oxidized at 200°C for 2 hours (Niox). After wettability tests the transverse sections of the solidified samples were subjected to shear strength trials, measurements of microhardness and structural observations by light microscopy and scanning electron microscopy in order to clarify the structure of phase boundaries in 226D/Ni and 226D/Niox pairs.
Keywords: wetting kinetics, microhardness, microstructure, carbon fibres, composites,
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Zenon A. Opiekun, Władysław A. Orłowicz
The article presents a course of static corrosion of spheroidal ferritic cast iron, austenite stainless steel X2CrNi19-12 (00H18N10) and samples of low-alloy construction steel 12CrMo4-5 (15HM) in liquid tin. The tests were performed at temperature of 600°C in liquid tin for 170 hours. It has been found, that the fastest corrosion was observed in austenite steel (average rate ca. 0.12 mm/h). Slower corrosion was observed in steel 12CrMo4-5 (average rate ca. 0.004 mm/h) and the slowest corrosion was observed in spheroidal ferritic iron cast specimen (average rate ca. 0.003 mm/h) in liquid tin.
Keywords: corrosion, austenitic steel, construction steel, spheroidal ferritic cast iron, liquid tin,
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Mieczysław Kuder, Stanisław Pysz
Thin-walled dome casts (hemispheres) with a wall thickness of 4.2 and 10.3 mm made of ductile iron underwent simulation tests within the frame of forecasting the tendency to create residual stresses, casting defects, the shaping of structures and strength properties of alloy in the walls of casts. The aim was to determine whether properties of casts would allow further production procedures and especially coating the surface with rubber by the method of high pressure rubber curing. It was stated that with the use of the developed technology the threat of possible defects in casts is insignificant and strength properties are sufficient to safely conduct further production operations.
Keywords: simulation tests, ductile iron, solidification, structure, strength,
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