The paper presents results of metallographic examination of faults occurring in the course of founding thin-walled cast-iron castings in
furan resin sand molds. A non-conformance of the scab type was Observed on surface of the casting as well as sand buckles and cold
shots. Studied the chemical composition by means of a scanning electron microscope in a region of casting defects: microanalysis point
and microanalysis surface. Around the observed defects discloses high concentration of oxides of iron, manganese and silicon.
A computer simulation of the casting process has been carried out with the objective to establish the cause of occurrence of cold shots on
casting surface. The simulation was carried out with the use of NovaFlow & Solid program. We analyzed the flowing metal in the mold
cavity. The main reason for the occurrence of casting defects on the surface of the casting was gating system, which caused turbulent flow
of metal with a distinctive splash stream of liquid alloy.
The paper is a presentation of a study on issues concerning degradation of protective paint coat having an adverse impact on aesthetic
qualities of thin-walled cast-iron castings fabricated in furan resin sand. Microscopic examination and microanalyses of chemistry
indicated that under the coat of paint covering the surface of a thin-walled casting, layers of oxides could be found presence of which can
be most probably attributed to careless cleaning of the casting surface before the paint application process, as well as corrosion pits
evidencing existence of damp residues under the paint layers contributing to creation of corrosion micro-cells
The excellent property combination of thin wall ductile iron castings (TWDI), including thin wall alloyed cast iron (e.g. austenitic TWDI) has opened new horizons for cast iron to replace steel castings and forgings in many engineering applications with considerable cost benefits. TWDI is considered as a potential material for the preparation of light castings with good mechanical and utility properties, the cost of which is relatively low. In this study, unalloyed and high Ni-alloyed (25% Ni) spheroidal graphite cast iron, with an austenitic metallic matrix were investigated. The research was conducted for thin-walled iron castings with 2, 3 and 5mm wall thickness, using different mould temperature (20°C, and 160°C) to achieve various cooling rates. The metallographic examinations i.e. characteristic of graphite nodules, metallic matrix, and primary grains of austenite dendrites (in high-nickel NTWDI) and mechanical properties were investigated. The study shows that homogeneity of the casting structure of thin-walled castings varies when changing the wall thickness and mould temperature. Finally, mechanical properties of thin-walled ductile iron castings with ferritic-pearlitic and austenitic metallic matrix have been shown.
The paper, which is a summary and supplement of previous works and research, presents the results of numerical and physical modeling of the GX2CrNiMoCuN25-6-3 duplex cast steel thin-walled castings production. To obtain thin-walled castings with wall in the thinnest place even below 1 mm was used the centrifugal casting technology and gravity casting. The analyzed technology (centrifugal casting) enables making elements with high surface quality with reduced consumption of batch materials and, as a result, reducing the costs of making a unitary casting. The idea behind the production of cast steel with the use of centrifugal technology was to find a remedy for the problems associated with unsatisfactory castability of the tested alloy.
The technological evaluation of the cast construction was carried out using the Nova Flow & Solid CV 4.3r8 software. Numerical simulations of crystallization and cooling were carried out for a casting without a gating system and sinkhead located in a mold in accordance with the pouring position. It was assumed that the analyzed cast will be made in the sand form with dimensions 250×250×120 mm.