The examinations of the extent of sinter reduction were carried out in simulated conditions of a blast- furnace at the temperatures of950 and I 100 °C. Two cokes with different reactivity were applied. An analysis was carried out to determine whether it was possible for the CO2, formed in situ as a result of sinter reduction by means of CO, to react with coke. It was shown, that at the temperature of 950 °C the reaction of CO2 with coke did not occur. The reduction of iron - bearing materials at that temperature occurs by way of indirect reduction without the participation of coke carbon. With the growth of temperature up to about 1100 °C the reaction CO2+ C = 2CO becomes an important process influencing the course of the reduction and coke consumption. The effect of coke reactivity on the course of direct reduction was also analysed. Increasing of coke reactivity results an increase in the amount of coke for the reaction CO2+ C= 2CO. The type of packing of the reduced sinter and coke influences the rate of the material reduction.

The methodology of determination of strain-rate sensitivity index was developed, based on hot rolling of a set of samples with the same draft but different speed at defined temperature levels. It was proved that initial grain size had nearly negligible influence on the investigated variable, in contrast to phase composition whose influence was remarkable. Combined influence of strain rate and temperature on deformation resistance of various types of steel was studied. For a selected group of steels an universal equation was set up, which described with a good accuracy impact of reciprocal temperature and chemical composition, expressed simply by nickel equivalent, on strain-rate sensitivity in hot stale.

Using the dilatometric method the densities of the solid Al-Li-Mg alloys were measured for two constant values oft=0.85 and 0.95, where t =X Al/ (X A 1 +X Mg) and for Li concentrations changing from O to 0.25 mole fraction. The experiments were carried out in the temperature ranges: 293-818 Kand 293-718 K fort= 0.05 and O. 15, respectively. The temperature dependences of density were described by the parabolic equation of the form y =a+ bT + cT 2. The parameters a, b, and c were calculated using the least squares method. It was found that the density isotherms fort= 0.95 show slight negative deviation from the linear behaviour, while fort= 0.85 an almost linear change is observed when plotting the density from Al-Mg alloys to pure Li density. The molar volume isotherms of Al-Li-Mg solid alloys calculated at the same temperatures as for the density are characterised by slow decreasing with the increase of Li content, except that calculated at 700 K for t = 0.85 showing an opposite trend.

The magnetic band separator is provided for the enrichment of strongly magnetic ores, as, for example, magnetite ore. The process of magnetic flocculation occurs under the influence of magnetic field. The forming particle aggregates (floes) contain non-magnetic particles in their structure which deteriorates the separation results. In the band separator the material is subjected to several remagnetizations on its separation path during which non-magnetic particles are being liberated from the floe volumes. The separation results depend on the characteristics of the separator magnetic system and magnetic properties of the raw material. Starting from the equations ofmagnetic field the author calculated the distribution of magnetic field and force in the band separator. On this basis he also determined the optimum pole pitch of the magnetic system which depends on particle sizes of the enriched raw material. Despite the magnetic force, also mechanical forces act upon particles. The balance of forces acting upon the particle enabled the value of separation magnetic susceptibility lo be calculated according to which the raw material is divided into magnetic and non-magnetic particles. Taking into account magnetic interactions between magnetite inclusions in the particle, the dependence of particle magnetic susceptibility on the volume content of magnetite was determined and, next, theoretical indexes of magnetite ore enrichment ability were calculated.

Fine equiaxial grain structure is a consequence of designing a material with a large contribution of intermetallic compounds of certain size and distribution. A 2XXX alloy with Fe, Ni, Mn and Zr additions was cast obtaining large amounts of Al-Fe-Ni and Al-Cu-Mg precipitates, in which the Al-Zr compounds appeared as dispersoids. After the application of a modified thermomechanical procedure, an alloy with average grain size of 12 μm with a large contribution of grains smaller than IO μm has been obtained. Apart from that, elongated precipitates of0.8-4.0 μmin size as well as globular ones about 0.3 urn large were produced in the alloy after recrystallization. The alloy revealed high resistance to grain growth at high temperatures, which was due to the appearance of intermetallic compounds (mostly Al-Fe-Ni) in grain boundaries.

Using SHSB technique, composites "in situ" based on intermetallic phase Ni3Al reinforced with particles of titanium carbides or borides were fabricated. The reinforcing phase was generated by spontaneous exothermic reaction proceeding in metal bath in a metaVnon-metal powdered briquette. Thus fabricated composites were free from porosity, possessed high thermodynamic stability and were characterised by absence of chemical reactions at the matrix-reinforcing particle phase boundary, which effectively prevented structure degradation under high-temperature service conditions. The nucleation of the reinforcing phase in molten metal matrix produced clean interfacial surface, free from the presence of oxides and adsorbed gas, and better wettability and coherence between the matrix and reinforcing particles. Owing to the possibility of controlling the parameters of the reaction kinetics during composite synthesis it was possible to generate particles of a required diameter, volume content and distribution and to obtain, consequently, the required level of the mechanical and tribological properties. An important advantage of this method is the possibility of finally shaping by means of casting process the elements and parts of machines. In accordance with ANSI H35. I we use such nomenclature of composite for example Ni3AVfi05p - matrix Ni3AI, type of reinforcement TiC, vol fraction 5%, p - particles.

The effect of tempearture, strain rate and strain on the structure and plastic properties of metals and alloys has been widely known, and improvement of above mentioned features by changes of deformation conditions only has been rather exhausted, but the effect of strain path changes is less known especially in the case of massive processes. Therefore the effect of different complex strain paths on behavior of CuSi3.5 silicon bronze has been investigated. The strain paths contain various sequences of cyclic torsion and monotonic tension were applied. The amplitude was changed in the range of 0.01-0.6, temperature 20-800 °C and strain rate O.Ol-I s _,_ The platic properties and structure obtained in complex strain paths were compared with those gained in monotonic torsion and tensile tests. The silicon bronze containing about 3.5 % Si has a very low stacking fault energy, therefore in the mechanism of complex deformation the twinnings and crystalographic slip play the imporatant role. The strain paths similar to those applied in the experiments are observed in some industrial processes. By proper chosen of the strain path the control of the flow stress and the limit strain can be obtained.

A Fe-4.34Ni alloy was solidified directionally in the Bridgman system. The solid-liquid interface has been frozen and doublet structure revealed. Energy Dispersive Spectroscopy proved that peritectic reaction had occurred during solidification and modified profile of solute redistribution within primary phase existed just before peritectic reaction. Energ Dispersive X-Ray Spectrimetry (EDXS) solute measurements confirmed also the influence of doublet tip splitting on the solute redistribution. The obtained profile of solute redistribution modified by tip splitting has been compared to analogous profile obtained for the Al-3.5Li alloy in which doublet structure has also been formed but peritectic reaction does not exist. However, in the latter some precipitates have been predicted and revealed by use of the Scanning Electron Microscopy. Relevant equations have been formulated in order to fit experimental solute redistribution within frozen morphology of the Fe-4.34Ni alloy. The formulated equations are an analytical description of the peritectic reaction. It employs the merastable solidus line position known from the Fe-Ni phase diagram. An orientation of the doublet topography has also been determined based on electron backscatter diffraction (EBSD) acquired from the Al-3.5Li doublet shaped cells solidified and frozen during microgravity test.