The article presents the results of the investigations performed on high manganese austenitic steel which underwent the test of uniaxial tension, with the application of electric current impulses. The application of low voltage impulse alternating current of high intensity during the plastic deformation of the examined steel caused the occurrence of the electroplastic effect, which changed the shape of the stress-strain curve. A drop of flow stress and elongation of the tested material was observed in the case of the application of electric current impulses, in respect of the material stretched without such impulses and stretched at an elevated temperature. The analysis of the morphology of the fractures showed differences between the samples tested under the particular conditions. An analysis of the alloy’s microstructure was also performed under different conditions. The application of electric current impulses can have a significant influence on the reduction of the forces in the plastic forming processes for this type of steel.

Acid mine drainage (AMD) is widespread environmental problem associated with both working and abandoned mining operation, resulting from the microbial oxidation of pyrite in presence of water and air, to form an acidic solution containing metal ions. The present study aims to adjust low pH, remove iron, manganese and sulphate from AMD generated at open pit Jiří and depth Jiří, Sokolovská uhelná, Czech Republic. The local AMD is very problematic due to its composition and process taking place in the Water Preparing Plant Svatava (WPPS), where only pH value is adjusted and mainly high concentration of iron and suspended solids are removed.

The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.

Concentrations of four trace elements, copper (Cu), zinc (Zn), manganese (Mn) and seleni- um (Se), have thus far proven to be affected by lentiviral infections in people and rhesus monkeys. As small ruminant lentivirus (SRLV) infection is responsible for one of the most important goat diseases, caprine arthritis-encephalitis (CAE), we evaluated serum and liver concentrations of Cu, Zn, Mn, Se in goats severely affected by symptomatic CAE and compared them with litera- ture reference intervals. Serum and liver samples of dairy goats euthanized due to severe clinical form of CAE were collected and screened for the concentration of Cu, Zn, Mn (54 serum sam- ples, 22 liver samples), and Se (36 serum samples, 22 liver samples) using flame atomic absorption spectrometry for Cu, Zn, Mn and graphite furnace atomic absorption spectroscopy for Se. In both serum and liver samples concentration of Zn was the highest, followed by Cu concentration, and then by Mn and Se. There was no relationship between serum and liver concentrations of trace elements. Liver concentrations of all four trace elements and serum Cu concentration fell within literature reference intervals, although liver Se concentration was mainly in the lower marginal range (between 0.4 and 1.0 mg/L). Serum Zn concentration was elevated (>1.2 mg/L) in all goats, serum Mn concentration was elevated (>0.04 mg/L) in 42 (78%) goats and serum Se concentra- tion was elevated (>1.6 mg/L) in 13 (36%) goats. Concluding, severe symptomatic CAE does not appear to be associated with the level of any of the four trace elements.

The article is focused on thermomechanical and plastic properties of two high-manganese TRIPLEX type steels with an internal marking 1043 and 1045. Tensile tests at ambient temperature and at a temperature interval 600°C to 1100°C were performed for these heats with a different chemical composition. After the samples having been ruptured, ductility was observed which was expressed by reduction of material after the tensile test. Then the stacking fault energy was calculated and dilatation of both high-manganese steels was measured. At ambient temperature (20°C), 1043 heat featured higher tensile strength by 66MPa than 1045 heat. Microhardness was higher by 8HV0,2 for 1045 steel than for 1043 steel (203HV0,2). At 20°C, ductility only differed by 3% for the both heats. Decrease of tensile properties occurred at higher temperatures of 600 up to 1100°C. This tensile properties decrease at high temperatures is evident for most of metals. The strength level difference of the both heats in the temperature range 20°C up to 1100°C corresponded to 83 MPa, while between 600°C and 1100°C the difference was only 18 MPa. In the temperature range 600°C to 800°C, a decrease in ductility values down to 14 % (1045 heat), or 22 % (1043 heat), was noticed. This decrease was accompanied with occurrence of complex Aluminium oxides in a superposition with detected AlN particles. Further ductility decrease was only noted for 1043 heat where higher occurrence of shrinkag porosity was observed which might have contributed to a slight decrease in reduction of area values in the temperature range 900°C to 1100°C, in contrast to 1045 heat matrix.

Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously

degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being

excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present

article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve

higher iron content (about 0.7 wt. % Fe). The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The

influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations.

The results indicate that increasing manganese content (> 0.2 wt. % Mn) lead to increase the temperature of solidification iron rich phase

(TAl5FeSi) and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At

adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

The results of the modification of austenitic matrix in cast high-manganese steel containing 11÷19% Mn with additions of Cr, Ni and Ti

were discussed. The introduction of carbide-forming alloying elements to this cast steel leads to the formation in matrix of stable complex

carbide phases, which effectively increase the abrasive wear resistance in a mixture of SiC and water. The starting material used in tests

was a cast Hadfield steel containing 11% Mn and 1.34% C. The results presented in the article show significant improvement in abrasive

wear resistance and hardness owing to the structure modification with additions of Cr and Ti.

Cast Hadfield steel is characterised by high abrasion resistance, provided, however, that it is exposed to the effect of dynamic loads.

During abrasion without loading, e.g. under the impact of loose sand jet, its wear resistance drops very drastically. To increase the abrasion

resistance of this alloy under the conditions where no pressure is acting, primary vanadium carbides are formed in the metallurgical

process, to obtain a composite structure after the melt solidification. The primary, very hard, carbides uniformly distributed in the

austenitic matrix are reported to double the wear resistance of samples subjected to the effect of a silicon carbide-water mixture.

Cast high-manganese Hadfield steel is commonly used for machine components operating under dynamic load conditions. Their high fracture toughness and abrasive wear resistance is the result of an austenitic structure, which - while being ductile - at the same time tends to surface harden under the effect of cold work. Absence of dynamic loads (e.g. in the case of sand abrasion) causes rapid and premature wear of parts. In order to improve the abrasive wear resistance of cast high-manganese steel for operation under the conditions free from dynamic loads, primary titanium carbides are produced in this cast steel during melting process to obtain in castings, after melt solidification, the microstructure consisting of an austenitic matrix and primary carbides uniformly distributed therein. After heat treatment, the microhardness of the austenitic matrix of such cast steel is up to 580 μHV20 and the resulting carbides may reach even 4000 μHV20. The impact strength of this cast steel varies from 57 to 129 and it decreases with titanium content. Compared to common cast Hadfield steel, the abrasive wear resistance determined in Miller test is at least twice as high for the 0.4% Ti alloy and continues growing with titanium content.

Widely used in the power and mining industry, cast Hadfield steel is resistant to wear, but only when operating under impact loads.

Components made from this alloy exposed to the effect of abrasion under load-free conditions are known to suffer rapid and premature

wear. To increase the abrasion resistance of cast high-manganese steel under the conditions where no dynamic loads are operating, primary

titanium carbides are formed in the process of cast steel melting, to obtain in the alloy after solidification and heat treatment, the

microstructure composed of very hard primary carbides uniformly distributed in the austenitic matrix of a hardness superior to the

hardness of common cast Hadfield steel. Hard titanium carbides ultimately improve the wear resistance of components operating under

shear conditions. The measured microhardness of the as-cast matrix in samples tested was observed to increase with the increasing content

of titanium and was 380 HV0.02 for the content of 0.4%, 410 HV0.02 for the content of 1.5% and 510 HV0.02 for the content of 2 and

2.5%. After solution heat treatment, the microhardness of the matrix was 460÷480 HV0.02 for melts T2, T3 and T6, and 580 HV0.02 for

melt T4, and was higher than the values obtained in common cast Hadfield steel (370 HV0.02 in as-cast state and 340÷370 HV0.02 after

solution heat treatment). The measured microhardness of alloyed cementite was 1030÷1270 HV0.02; the microhardness of carbides

reached even 2650÷4000 HV0.02.

In Al-Si alloy the iron is the most common impurity and with presence of other elements in alloy creates the intermetallic compounds,

which decreases mechanical properties and increases of porosity. The cause of the negative effect of intermetallic particles on the

mechanical properties is that it is more easily break off the tension load as the aluminium matrix or small particles of silicon. By adding

suitable alloying elements, also known as iron correctors, is possible to reduce this harmful effect.

In the article is evaluated influence of manganese on microstructure with performed EDX analysis selected intermetallic phases and tensile

test and measurement of length of Al5FeSi phase. For realization experiments was used AlSi7Mg0.3 alloy with increased iron content.

Manganese was added in the amount 0.3 wt. %, 0.6 wt. %, 0.8 wt.% and 1,2 wt. %. From performed measurements it has been concluded,

that increased amount of manganese, i.e. Mn/Fe ratio, does not have significant influence on mechanical properties AlSi7Mg0.3 alloy in

the melted state.

The paper deals with the influence of manganese in AlSi7Mg0.3 alloy with higher iron content. Main aim is to eliminate harmful effect of intermetallic – iron based phases. Manganese in an alloy having an iron content of about 0.7 wt. % was graded at levels from 0.3 to 1.4 wt. %. In the paper, the effect of manganese is evaluated with respect to the resulting mechanical properties, also after the heat treatment (T6). Morphology of the excluded intermetallic phases and the character of the crystallisation of the alloy was also evaluated. From the obtained results it can be concluded that the increasing level of manganese in the alloy leads to an increase in the temperature of the β-Al5FeSi phase formation and therefore its elimination. Reducing the amount of β-Al5FeSi phase in the structure results in an improvement of the mechanical properties (observed at levels of 0.3 to 0.8 wt. % Mn). The highest addition of Mn (1.4 wt.%) leads to a decrease in the temperature corresponding to the formation of eutectic silicon, which has a positive influence on the structure, but at the same time the negative sludge particles were also present

Our scientific research is based on oxidation reactions and monitoring of chemical reaction kinetics in the Velekinca groundwaters plant in Gjilan municipality, Kosovo. The GW of this plant contains high concentration of manganese so we need to use potassium permanganate (KMnO4) as one of the most power oxidants in the water treatment plant. In our re-search the high concentration of Mn in groundwaters is 0.22–0.28 mg∙dm–3 and this concentration is not in accordance with the WHO. Chlorine is one of the most common disinfectants used in the water treatment industry because it has a low cost and immediate effect on the destruction of microorganisms, the concentration of chlorine (Cl2) in our research is 0.1–0.32 mg∙dm–3. The speed of chemical reactions in the technology of GW is extremely important because sometimes in the elimi-nation of chemical pollutants using oxidizing agents often form intermediate species. The speed of reactions indicates how fast chemical bonds are formed in the creation of a product, and this depends on the rate of reaction (XA). The focus for the research is to study the potassium permanganate and chlorine gas reactions in water if it forms intermediate products (in-termediate species) due to the high speed of reactions. Scientific research conclusion, intermediate species in the oxidation reactions of Mn and water disinfection with Cl2(g) it is impossible to cause a high rate of chemical reactions from the reac-tion rate (XA = 1%) to the reaction rate (XA = 99%). The maximum speed at the highest XA Cl2 is from 4.405∙10–11 to 8.87∙10–10 mol∙dm–3∙s–1, while at Mn is (2.030–4.034)∙10–7 mol∙dm–3∙s–1.