B. Kosec, L. Kosec, S. Petrović, V. Gontarev, G. Kosec, M. Gojić, P. Škraba - Analysis of Low-Carbon Steel/Tantalum Interface After Explosive Welding

     The article discusses the morphology, microstructure and chemical composition of the boundary layer in explosive welding of low-carbon steel and tantalum plates. Pools of melt composed of both metals and having a heterogeneous chemical composition appear on the boundary layer. This phenomenon is the result of incomplete mixing of both: molten metals due to rapid cooling and solidification. Within the pools of alloy, a large number of non-metallic oxide inclusions, products of deoxidation of molten alloys, can be found. The non-metal inclusions are round (0.1 to 2 µm in diameter) and vary in both: size and chemical composition. The main component of the non-metal inclusions is Ta₂O₅, which also contains iron, manganese, and aluminium oxides. The number of non-metal inclusions is unusually high for low-carbon steel and comparable to the number of non-metal inclusions in welds. Oxygen which causes the large number of deoxidised products does not originate in the low-carbon steel, as this steel is relatively clean. The most probable source of oxygen is the oxide scale from the surface of the low-carbon steel, which was poorly cleaned prior to welding. pdf - 282 kB

A. Bukhanovsky, I. Mamuzić, V. Borisenko - Interrelation Between the Structural State of Material and Mechanical Properties of Low-Alloyed Molybdenum Alloys

     As a result of joint analysis of experimental data on the structure and mechanical properties of low-alloy molybdenum alloys of the systems Mo-Al-B, Mo-Zr-B, Mo-Zr-Hf-B and Mo-Re we have established that for considered class of materials over the wide range of temperature there exist close correlations between the structural state, short-term, and low-cycle and high-cycle fatigue strength characteristic. pdf - 231 kB

Y. Sidor, F. Kovac - Quantification of Microstructure and Evaluation of Mechanical Properties in Non-Oriented Electrical Steels

    This paper presents an original method of the estimation of average grain size in microstructure of broad grain size distribution and the parameter, describing the homogeneity of microstructure. The coefficient of microstructure homogeneity is defined. The mechanical properties of non-oriented electrical steels are predicted using new equation of grain size estimation. pdf - 190 kB

J. Grabian - An Analysis of Geometric Conditions in the Process of Infiltrating the Reinforcement of Cast Metal Matrix Composites

     An analysis was made in the first stage of producing casts from saturated metal composites, which consist in the penetration of liquid metal into the depths of the reinforcement. For most of the materials applied both the matrix and the reinforcements of the composites this process is difficult because of poor wettability of the ceramic reinforcement by liquid metal. Pressure is the enforcing factor. It is easy to select this pressure when the shape and dimensions of the space between reinforcement fibres can be geometrically described; this occurs when the reinforcement fibres are ordered. For composites of disordered fibres it is practically impossible to describe the space geometry between fibres. It has been proved that the stage of filling with metal the closed capillary spaces formed by fibres touching one another is decisive in the saturation process. It has also been proved that the process of saturating the reinforcement with disordered fibres should be examined on a macroscopic scale. pdf - 356 kB

M. Dzubinsky, F. Kovac, A. Petercakova - New Form of Equation for Deformation Resistance Prediction Under Hot Rolling Industrial Conditions

     A new equation for the prediction of steel deformation resistance under industrial hot rolling conditions is proposed. This new expression can be used for more accurate description of material deformation behavior at service conditions utilizing data from laboratory plastometer experiments. pdf - 142 kB

V. Goryany, I. Mamuzić, T. Hlyntseva, V. Radsinsky - Thermal Strengthening of the Low-Carbon Steel Strip

    The results of research of microstructure and mechanical properties of the strips cross-section 45x6 and 30x8 mm from low carbon steel in hot-rolling condition and after accelerated cooling of different intensity and schemes of the coolers movement in the cooling chambers are shown. Regimes that provide the high level of steel’s strength with the smallest changing of the mechanical properties by the length of the rolled strip were defined. pdf - 170 kB

R. Budzik, R. Prusak, Z. Skuza - Change in the Organizational Structure of a Restructured Metallurgical Enterprise on the Example of one of the Largest Polish Steelworks

     Among metallurgical enterprises active contemporarily on the market a great concern about the simplification of the organizational structure can be observed. The main factor decisive to an enterprise’s choice to introduce changes in the field of organization and management are changes of conditions in its environment. In addition to this, the managements of metallurgical enterprises mention also, as causal factors, a general crisis of an enterprise that manifest itself in a decrease of basic economic indices, inadequate adjustment of information and decision systems to the variable character of an environment and starting changes in other areas, such as engineering or economics. In this paper the effects of the restructuring of the organizational structure of Katowice Steelworks are presented. pdf - 113 kB

A. Kawałek, H. Dyja, J. Markowski - Effect of Asymmetrical Rolling on Broadening of the Product Line of Rolled Sheets

     An analysis of asymmetrical band rolling in the last two stands of a finishing sheet hot rolling mill has been performed in the study. Investigations were carried out to determine the range of values of roll peripheral speed asymmetry ratios which would assure the permissible bending of band upon its exit from the roll gap and to reduce the value of the overall metal pressure on the rolls without causing overloading of the drives of the finishing group of the continuous sheet rolling mill. The application of asymmetrical rolling on the last two stands has made it possible to reduce deviations in band thickness, decrease the minimum thickness of finished sheet from 2.00 mm to 1.80 mm and increase the width of sheets produced in the thickness range from 1.80 - 2.00 mm to above 925 mm. pdf - 137 kB