PRODUCTION OF THREE-LAYER STEEL BIMETALLIC STRIPS IN THE UNIT OF CONTINUOUS CASTING AND DEFORMATION. REPORT 2

The paper states urgency of the problem of determining stressstrain state of metals of the cladding layer and the main strip in production of three-layer bimetal: alloyed steel-constructional steelalloyed steel. Temperature field of the main strip and cladding layer is given to calculate stress-strain state of metals of three-layer bimetallic strip. Initial data for calculating this stress-strain state are given. To assess the effect of coefficient of friction between cladding layer s and the main strip on stress-strain state of metals in deformation zone, three values of it are taken. Geometric model is described for calculating stress-strain state and metal flow in deformation center of cladding layer. Characteristic lines and points of calculation are provided. Technique for solving the problem of determining stresses and flows in deformation focus is described by finite element method using ANSYS app. Regularities of flow of cladding layer’s metal along the length of deformation center and movement of the main strip of bimetallic ingot are given. Values of mutual displacement of layers of bimetallic strip are determined as a function of deformation degree of the cladding layer. And the recommendations are given on this degree to improve quali ty of a three-layer bimetal. Regularities of distribution of axial and tangential stresses in deformation center are presented for production of steel three-layer bimetallic strips in the unit of combined continuous casting and deformation. Stress state of the cladding layer’s metal in focus of cyclic deformation was estimated from the position of improving quality of three-layer bimetallic strips produced in such unit.

Scientific problem of metal melts. Solutions

In the existing theories of liquid state of metals and alloys the basic structural element is atom. It creates a serious problem in scientific understanding of the mechanism of process of melt and properties of metal melts. For the solution of this problem it is necessary to consider that the basic structural element of liquid metals and alloys is the nanocrystal. As a result of researches it was set that metal melts are the equilibrium two-phase systems consisting on average of 97% from nanocrystals and of 3% from atoms, which form an unstructured zone.

Immobilization of Sr2+, Bi3+ and Zn2+ in Alkali-Activated Materials Based on Blast Furnace Slag and Fly Ash

It is well known, that alkali-activated materials (AAMs) are suitable for immobilization of heavy metals and other hazardous materials. This study is focused on the characterization of inhibition of three metals – Sr2+, Bi3+and Zn2+in alkali-activated matrices. Two type of matrices were prepared – alkali-activated blast furnace slag (BFS) and alkali-activated fly ash (FA). Sodium water glass was used as alkaline activator. The ability of these matrices to fix the metals were proved by leaching tests. Compressive strength was measured to characterize mechanical properties of the matrices. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) was used to examine distribution and chemical state of metals within the matrices. The observed metals mainly formed the insoluble compounds after alkali activation.

Effect of the Chemical Composition of Mesoporous Cerium-Zirconium Oxides on the Modification with Sulfur and Gold Species and Their Application in Glycerol Oxidation

Ceria, zirconia and mixed cerium-zirconium mesoporous oxides were synthesized and used as supports for sulfur and gold species. The materials were characterised using selected advanced techniques (ICP-OES, elemental analysis, XPS, XRD, N2 adsorption and desorption isotherms, UV-vis, ATR-FTIR, TPR-H2, TG-DTA) which allowed monitoring of the oxidation state of metals (cerium and gold) and the surface properties of the catalysts, in particular the concentration of the components on the surface and in the bulk of materials. The interactions between gold, sulfur and metals from oxides were considered. The goal of this work was studied the changes in the chemical composition of materials and the oxidation states of cerium species after the modification of oxides with sulfur and gold species and the estimation of the influence of these changes on the surface properties. The chemical composition of surface affects the mobility of surface oxygen and the oxidation state of cerium, which can play the role of redox sites (e.g. Ce3+/Ce4+ species), and therefore it strongly influences on the adsorption of hydrogen sulfide and then gold loading. Additionally, gold catalysts modified with sulfur species were tested in the reaction of glycerol oxidation in the liquid phase at basic conditions as the test reaction of the catalytic oxidation of organic pollutants from water.