Results of a study on influence of Cr, Mo and Al on the microstructure, abrasive wear and corrosion resistance of Ni-Mn-Cu cast iron in the as-cast and heat-treated conditions are presented. Because of the chilling effect of first two elements (tendency to create hard spots), graphitising Al was added to the alloys, with the highest concentration of Cr and Mo. All castings in the as-cast condition showed an austenitic matrix, guaranteeing good machinability. Heat treatment of raw castings, consisting in annealing at 500 °C for 4 h, resulted in partial transformation of austenite. As a result the carbon-supersaturated acicular ferrite, morphologically similar to bainitic ferrite was formed. The degree of this transformation increased with increasing concentrations of Cr and Mo, which successively decreased the thermodynamic stability of austenite. A change of matrix structure made it possible to significantly increase hardness and abrasive-wear resistance of castings. The largest increment of hardness and abrasion resistance was demonstrated by the castings with the highest total concentration of Cr and Mo with an addition of 0.4% Al. Introduction of Cr and Mo also resulted in an increase of corrosion resistance. In the heat-treated specimens, increasing the concentration of Cr and Mo resulted in a successive decrease of the depth of corrosion pits, with an increase in their number at the same time. This is very favourable from the viewpoint of corrosion resistance.

In the paper, the effects, on basic usable properties (abrasive wear and corrosion resistance), of solidification (acc. to the stable and non-stable equilibrium system) and transformations occurring in the matrix during the cooling of castings of Ni-Mn-Cu cast iron were determined. Abrasive wear resistance was mainly determined by the types and arrangements of high-carbon phases (indicated by eutectic saturation degree), and the kinds of matrices (indicated by the nickel equivalent value, calculated from chemical composition). The highest abrasive wear resistance was found for white cast iron, with the highest degree of austenite to martensite transformation occurring in its matrix. Irrespective of solidification, a decrease of the equivalent value below a limit value resulted in increased austenite transformation, and thus, to a significant rise in hardness and abrasive wear resistance for the castings. At the same time, corrosion resistance of the alloy was slightly reduced. The examinations showed that corrosion resistance of Ni-Mn-Cu cast iron is, too a much lesser degree, decided by the means of solidification of the castings, rather than transformations occurring in the matrix, as controlled by nickel equivalent value (especially elements with high electrochemical potential).

The aim of this study was to attempt to use barley malt as a natural, organic binder in the technology of molding sand. TGA analysis of the binder was performed, during which temperatures of thermal decomposition of its components were determined. The results of TG/DTG analysis show that a loss of ~75% of mass of the MB binder is organic matter. Over 50% of this is starch. The results indicate the possibility of using a binder made of barley malt as a binding material for quartz sand grains. This fact was confirmed by tests carried out with use of SEM. During the observations, it was found that barley malt forms smooth bridges connecting individual grains of quartz sand. The typical properties of molding sands with barley malt were also determined, compared to sands containing commonly used binders. At the same time, the influence of the content of this binder on flowability, permeability, strength properties, and wear resistance was assessed. It has been found that increasing the binder content in molding mass results in an increase in strength and wear resistance, as opposed to flowability and permeability. Test castings were also made. It was found that the addition of a binder made of barley malt has a positive effect on the surface quality of castings. This was confirmed by roughness measurements of the test castings. At the same time, a tendency to excessive gas evolution during pouring was shown, with higher contents of this binder. Moreover, greater amounts of barley malt in the molding sand (MB 5%) as compared to the lower content (MB 2%) increased the thickness of the burnt layer of the sand by 25%. This is due to the exothermic reaction when more binder is burnt. It is extremely important from the point of view of the regeneration of molding sand.

The aim of the following work was to determine the possibility of using barley malt as a binder in moulding sands technology. The moulding sands prepared on the basis of three kinds of sands, i.e. quartz, olivine and chromite sands were analyzed. In order to determine the properties of moulding sands, typical determinations were made, i.e. moisture content, flowability, permeability, strength properties and abrasion wear. The obtained results indicate that it is possible to use barley malt as an independent binder for masses made of quartz, olivine and chromite sands.

The requirements placed on the foundry industry are mainly related to the need to maintain an appropriate quality–price ratio of the product and to maintain an appropriate production regime that takes into account modern legal solutions related to environmental protection. This work is part of the trend of searching for new or previously unused materials from renewable sources in moulding sand technology. This article concerns the possibility of using barley malt in moulding material technology as a binding material. The presented work contains the results of research on the release of gases during casting, where high temperatures cause the decomposition of chemical substances. The tests confirmed that moulding sands with barley malt as a binder do not cause excessive emissions of harmful gaseous products when pouring moulds with liquid casting alloy. The volume of gases formed was smaller than that of commonly used moulding sands with other binders. The total volume of gases produced and the kinetics of their release indicate that casting in this type of moulding sand did not cause any technological inconvenience or casting defects of gaseous origin. This was confirmed by research involving obtaining iron castings in industrial conditions using barley malt as a binder in moulding sand technology, which were then subjected to visual assessment and roughness analysis.