Modeling of the Formation of AlN Precipitates During Solidification of Steel

The study was carried out computer simulations of the formation process of AlN precipitates in the solidification of steel. The chemical composition of steel and non-metallic inclusions formed was determined using the commercial software FactSage. Calculated amount of precipitates formed during cooling of steel between the liquidus and solidus temperatures under conditions of thermodynamic equilibrium. In parallel, the computations were performed using your own computer program. It was found that aluminum nitride is formed at the final stage of solidification, and the condition of its formation is low oxygen content in steel

Metallographic and corrosion research of copper from archaeological sites

In this study, copper slabs - ingots, from both Gdańsk and Krakow were examined. Besides metallographic examinations, attention was focused on analyses of corrosion products. The following techniques were applied: scanning electron microscopy with fluorescent X-ray microanalysis and X-ray diffraction. The conducted investigations enabled determination of the causes of corrosion in the old copper slabs, due mainly to the mediaeval alloying techniques and copper processing technologies

Refining processes in the copper casting technology

The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup) and modifying (ODM2, Kupmod2) formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameters were tested for a chosen chromium copper content, based on the criterion of hardness and electrical conductivity tests. Searching for materials with high wear resistance, the influence of variable silicone content on the properties of CuNiSi alloy was researched

Influence of refining treatments on the properties of Al-Si alloys

The article focused on researching the influence of Ti, B, Sr and Na as a modifying treatment elements for Al-Si alloys. The influence of alloying additives such as Cu and Cr was studied. Tensile strength Rm, elongation A5 and HB hardness was analysed, as well as the influence of the above-mentioned elements on the microstructure and solidification of alloys containing a varied content of Si, within the 7 ÷ 16 % range. The influence of heat treatment on the alloy properties was also researched

Copper alloys in investment casting technology

This paper presents research results in the field of casting technology of copper and copper alloys using the investment casting technology, both from historical as well as modern technology perspective. The analysis of exemplary elements of the old casting moulds is included, as well as the Bronze Age casts. The chemical content of various copper alloys was determined and the application of lost wax method was confirmed in the Bronze Age workshop. At present, investment casting method is used for manufacturing high-quality casts, especially products for power engineering that is why it demands respecting very rigorous technological requirements. The casts were characterised based on microstructure research, chemical composition and conductivity in relation to oxygen content

Conception of a hybrid pneumatic-combustion rotary vane engine - challenge and reality

The paper presents a new concept of applying a rotary vane engine working as the hybrid system including both a combustion engine and a pneumatic motor, which were working simultaneously. In the beginning, review on both unconventional piston engine designs and similar like solutions on rotary vane engines were conducted. Next, description of the conceptual engine was presented. The concept was realized in practice. The prototype engine was built and it was preliminary investigated focusing on problems with cold start and misfiring events which occurred. The engine was tested on LPG and gasoline, however, its main target is to feed it with natural gas. This approach is justified as far as the engine finally might work in natural gas reduction stations and would provide electricity of 1kW power for station’s own demands

Researching the Influence of Chemical Composition and Technological Parameters on the Quality of Copper Alloys

The work presents the results of process efficiency of refining liquid copper with special refining agents and the analysis results of the influence of alloying components on the structure and properties of the chosen alloys. The research undertaken aimed at evaluation of the influence of alloying additives, such as aluminium, silicon and also cobalt in the chosen Cu-Zn alloys. The microstructures were researched with the help of light and scanning microscopy together with X-ray microanalysis to determine significant changes of mechanical properties

Computer simulation of process in molten oxide slag reduction

Praca zajmuje się termodynamiczną analizą elementarnych procesów chemicznych zachodzących podczas redukcji żużla zawierającego tlenek miedzi. Redukcja żużla zachodzi przez zastosowanie reduktora w postaci stałej - węgla, gazowej - tlenek węgla lub węgla rozpuszczonego w ciekłym żużlu. Obecna praca rozpatruje dwa procesy chemiczne: reakcję ciekłego żużla z węglem oraz z tlenkiem węgla. Korzystając z komercyjnego oprogramowania FATSage obliczono w warunkach równowagi termodynamicznej składy faz dla układów: stały węgiel – ciekły żużel - stop Cu–Fe–Pb – faza gzowa oraz gazowy CO – ciekły żużel – stop Cu–Fe–Pb – faza gazowa. Symulację prowadzono dla temperatury procesu 1500, 1600, 1700 K. Gazowe produkty reakcji redukcji i stop Cu–Fe–Pb były usuwane z układu w każdym kroku obliczeniowym. Uzyskane wyniki obliczeń wykazały, że redukcja za pomocą węgla odgrywa zasadniczą rolę w procesie odzysku miedzi.The present work deals with thermodynamic analysis of process of the reduction of molten slag containing copper oxide. Reduction of liquid slag is possible with solid carbon, gaseous carbon oxide. and carbon dissolved in liquid slag. This work studied two chemical reactions of liquid slag containing copper oxide: with solid carbon and gaseous CO. Thermodynamic equilibrium in the system: solid carbon – liquid slag – metallic alloy Cu–Fe–Pb – gas and gaseous CO – liquid slag – metallic Cu–Fe–Pb – gas were calculated by means of FACTSage software. The simulation of the progress of reduction process at 1500, 1600, 1700K was obtained under assumption that the gaseous reduction products and metallic alloy Cu–Fe–Pb were removed from consideration after each simulation step. The calculation revealed that consumption of reducing agent is much higher in the case of CO reduction. The effect of simulation suggested, that reduction with solid carbon is the predominant mode of industrial process