The paper analyses the as-cast state structure of chromium cast iron designed for operation under harsh impact-abrasive conditions. In the process of chromium iron castings manufacture, very strong influence on the structure of this material have the parameters of the technological process. Among others, adding to the Fe-Cr-C alloy the alloying elements like tungsten and titanium leads to the formation of additional carbides in the structure of this cast iron, which may favourably affect the casting properties, including the resistance to abrasive wear.

To investigate the adsorptive properties of a local laterite deposited in Chenzhou, Hunan province, China, the adsorptive properties of the natural laterite were investigated by batch technique in this study. The effects of contact time, pH, ionic strength, temperature, and the concentration on adsorption properties were also analyzed. The obtained experimental results show that the main mineral composition of laterite is kaolinite and montmorillonite. The adsorption process achieved equilibrium within 60 minutes and 90 minutes for Sr(II) and Cr(VI), respectively. The adsorption capacities for Cr(VI) and Sr(II) by the laterite were about 7.25 mg·g^-1 and 8.35 mg·g^-1 under the given experimental conditions, respectively. The equilibrium adsorption data were fitted to the second-order kinetic equation. The adsorption capacity for Sr(II) onto the laterite increased with increasing pH from 3–11 but decreased with increasing ionic strength from 0.001 to 1.0 M NaCl. The Sr(II) adsorption reaction on laterite was endothermic and the process of adsorption was favored at high temperature. Similarly, the adsorption capacity for Cr(VI) onto the laterite increased with increasing pH from 3–11, however, the ionic strength and temperature had an insignificant effect on Cr(VI) adsorption. The adsorption of Cr(VI) and Sr(II) was dominated by ion exchange and surface complexation in this work. Furthermore, the Langmuir and Freundlich adsorption isotherm model was used for the description of the adsorption process. The results suggest that the studied laterite samples can be effectively used for the treatment of contaminated wastewaters.

The purpose of the study was to optimize the removal of Cr(VI) by means of the Trichoderma viride strain isolated from chromium mud samples a well as the Aspergillus niger and Penicillium citrinum strains from other environments. The growth of organism and removal of chromium(VI) was carried out in water solution of various chromium(VI) contents. The research was carried out at optimal pH for each fungus i.e. Aspergillus niger 4.0, Penicillium citrinum 5.0 and Trichoderma viride 4.5. During 14 days of incubation, samples of 5 ml each were collected every day in order to determine chromium(VI) content in the solution and the efficiency of bioaccumulation of this element was then specified. Furthermore, chromium contents in filtrate and mycelium were checked to verify this type of biological activity of microorganisms. The fungi culture investigated in this study could grow at 10-125 mg/l chromium concentration which indicated that it was characterized by high tolerance to various concentrations of chromium. At 125 mg/l chromium, these organisms could accumulate successfully about 90% of chromium. High tolerance of this culture can make it a potential candidate to be a heavy metal scavenger of chromium.

The present paper is a presentation of results of a study on morphology, chemical composition, material properties (HVIT, HIT, EIT), and nanoindentation elastic and plastic work for carbide precipitates in chromium cast iron containing 24% Cr. It has been found that the carbides differ in chemical composition, as well as in morphology and values characterizing their material properties. The carbides containing the most chromium which had the shape of thick and long needles were characterized with highest values of the analyzed material properties.

In this paper, aluminium alloy of grade ADC-12 was considered as a base metal and chromium carbide (Cr3C2) particles were reinforced through friction stir process. A detailed analysis of mechanical property and metallurgical characterization studies were performed to evaluate the surface composite. Remarkable changes were observed in the developed composite due to the mechanical force produced by the stir tool with an increase in hardness. The metallurgical investigation infers that the presence of silica in ADC-12 alloys has undergone mechanical fracture and long needle structure changed to reduced size. On the other hand, at higher tool rotational speed, the uniform distribution of hard particles was confirmed through SEM micrographs. Thus the modified surface composite has produced good mechanical property with high metallurgical qualities.

The results of research on stereological parameters of carbides in modified hypoeutectic chromium cast iron were shown in the paper. The

effect of distance the casting heat centre of casting to the carbide phase morphology was examined. The samples for metallographic

examination were taken from various locations of the model casting prepared in a special tester. This model casting was designed to

simulate the solidification of heavy castings. Using the proposed methodology the relation of the distance from the model mould and the

size, perimeter, length, width and the shape factor of carbides was examined. During the analysis, the values of stereological parameters of

carbides changed on various sections of the model casting.

Laboratory and field experiments have been conducted to study mobility of chromium and lead in

floodplain sediments. The main goal of the research was to verify a hypothesis whether changes of chromium

and lead concentration could be used to estimate the relative age of floodplain deposits. The basis for undertaking such research was the presence of weaving industry centers in the Obra River valley between the 16th and

the 19th century and using Cr and Pb compounds in paint recipes. The Cr and Pb contents were also analyzed in

three vertical profiles unaffected by the field experiments. The age of organic sediments in each of the profiles

was determined using the radiocarbon analysis. The results of the laboratory experiments have shown that the

highest contents of the elements were noted in the surface layer of the sediments placed in the column. However,

the contents decreased during the last phase of the experiments and both vertical and horizontal migration of

both elements was observed. A more intensive mobility was observed in the field test. Its cause could be the

changes of the groundwater level, floodplain inundation and pH conditions in alluvial deposits. Such processes

may have influenced migration of the compounds originating from the weaving industry production; Cr and Pb

contents detected in the profiles unaffected by the field experiment were too small to be used for relative dating of alluvial deposits. Moreover, the alluvial deposits with increased contents of the studied elements may be

older than the period of the weaving industry development. Cr and Pb mobility was especially intensive in the

profiles situated within the near bed zone of the floodplain due to regular inundation, and the activity of erosion

and accumulation processes entraining the studied elements back to transport in the river bed.

The present investigation focuses on the study of the influence of titanium inoculation on tribological properties of High Chromium Cast Iron. Studies of tribological properties of High Chromium Cast Iron, in particularly the wear resistance are important because of the special application of this material. High Chromium Cast Iron is widely used for parts that require high wear resistance for example the slurry pumps, brick dies, several pieces of mine drilling equipment, rock machining equipment, and similar ones. Presented research described the effects of various amounts of Fe-Ti as an inoculant for wear resistance. The results of wear resistance were collated with microstructural analysis. The melts were conducted in industrial conditions. The inoculation was carried out on the stream of liquid metal. The following amount of inoculants have been used; 0.17% Fe-Ti, 0.33% Fe-Ti and 0.66% Fe-Ti. The tests were performed on the machine type MAN. The assessment of wear resistance was made on the basis of the weight loss. The experimental results indicate that inoculation improve the wear resistance. In every sample after inoculation the wear resistance was at least 20% higher than the reference sample. The best result, thus the smallest wear loss was achieved for inoculation by 0.66% Fe-Ti. There is the correlation between the changing in microstructure and wear resistance. With greater amount of titanium the microstructure is finer. More fine carbides do not crumbling so quickly from the matrix, improving the wear resistance.

The present work, presented the study of effect of different inoculants on impact toughness in High Chromium Cast Iron. The molds were

pouring in industrial conditions and samples were tested in laboratory in Faculty of Foundry Engineering at AGH. Seven samples were tested

- one reference sample, three with different addition of Fe-Ti, and three with different addition of Al. The samples were subjected to impact

toughness on Charpy hammer and the hardness test. The presented investigations indicate that for the each inoculant there is an optimal

addition at which the sample obtained the highest value of impact toughness. For the Fe-Ti it is 0.66% and for Al is 0.17%. Of all the

examined inoculants best results were obtained at a dose of 0.66% Fe-Ti. Titanium is a well-known as a good modifier but very interesting

results gives the aluminum. Comparing the results obtained for the Fe-Ti and Al can be seen that in the case of aluminum hardness is more

stable. The hardness of all samples is around 40-45 HRC, which is not high for this type of cast iron. Therefore, in future studies it is

planned to carry out the heat treatment procedure that may improves hardness.

The article presents results of heat treatment on the high chromium cast iron. The study was carrying out on samples cut from the casting

made from chromium cast iron. Those were hardened at different temperatures, then tempered and soft annealed. The heat treatment was

performed in a laboratory chamber furnace in the Department of Engineering Alloys and Composites at Faculty of Foundry Engineering

AGH. At each stage of the heat treatment the hardness was measured by Vickers and Rockwell methods, and the microscope images were

done. Additionally based on images from the optical microscope the microstructure was assessed. Based on these results, the effect of

hardening, tempering and soft annealing on the microstructure and hardness of high chromium cast iron was studied. Next the effects of

different hardening temperatures on the properties of high chromium cast iron were compared. The study led to systemize the literature

data of the parameters of heat treatment of high chromium cast iron, and optimal conditions for heat treatment was proposed for casts of

similar properties and parameters.

The paper presents results of Ti-addition to High Chromium Cast Iron (HCCI) on the structure and selected mechanical properties. For this

study casted two sets of cylinders with dimensions ø20 mm, ø15 mm x 250 mm, for the High Chromium Cast Iron (HCCI) and with the

4% by mass Ti-addition. Melts were performed in the induction furnace crucible capacity of 15 kg. During the heats the cup with installed

S type thermocouple was poured to record the cooling curves. The cylinders were subjected to the static bending strength test. Samples for

the test microstructure and Rockwell hardness were cut from the cylinders. The study shows that the addition of titanium had an impact on

the structure and thus the properties of High Chromium Cast Iron (HCCI). In subsequent studies, through an appropriate choice of

chemical composition and proper process control, it is planned to obtain in the structure the titanium carbides TiC and chromium carbides

with type (Cr, Fe)7C3.

Paper presents the results of studies on primary crystallization and wear resistance of high chromium cast iron inoculated with

ferrotitanium intended for work in abrasive conditions. Primary crystallization was examined with use of TDA method, wear tests of the

samples were conducted using the modified pin-on-disk method.