Currently, biosoluble materials are widely used for the manufacture of implants, among which the most promising are magnesium alloys. Magnesium is a natural element of the body -it is contained in bone and muscle tissue, is involved in various metabolic processes. In addition, magnesium and its biocorrosion products have excellent biocompatibility. The main advantage of magnesium alloys is the positive effect of magnesium on the human body, but their quality does not meet the requirements for their use in the human body. It is possible to increase the properties of magnesium alloys as a result of improving the processes of refining and modification of liquid melt. The technology of modification of cast magnesium alloys of Mg-Zr-Nd system by dispersed graphite powder is proposed. It is shown that the optimal carbon additive in the amount of 0.05 -0.1 wt% C improves the mechanical properties due to grain grinding and additional strengthening of structural components. A complex filter containing equal amounts of magnesite, graphite and limestone is proposed, which provides an increased level of refining of the melt to obtain high quality casting. It is shown that the use of a complex carbon-containing filter provides not only efficient refining of the melt, but also its additional modification. In the structure of the alloy there is an increased amount of intermetallic γ-phase, which increases the microhardness of the structural components of the alloy and improves its physical and mechanical characteristics.

The paper implements a method for analyzing the stress-strain state of rectangular hollow sections (RHS) by finite-element modeling (FEM) of tests for three-point bending and torsion. Design schemes, 3-D solid-state and deformable models have been developed using the automated analysis and CAD/CAE system software, made it possible to obtain equivalent stress distributions and displacements in models. A simulation of tests for RHS with a cross section of 40 mm × 50 mm, manufactured in two ways, was carried out: (a) by direct-forming of galvanized steel strips on roll-forming mill in a semi-closed section with a longitudinal gap of 0.5 mm between the edges formed on a 40 mm web (DF-RHS); (b) similar direct-forming to the closed section and next welding the edges to a longitudinal weld along the web middle of 50 mm (DFW-RHS). RHS with various wall thicknesses (t = 1.93 mm, 1.84 mm and 0.7 mm) was investigated, given the design features that depend on the manufacturing processes of structural sections. It was found DFW-RHS is stiffer by at least 50% compared to DF-RHS, which allows to savings the metal by reducing the RHS wall thickness by 62% while maintaining the same stiffness and ensuring high strength of structural section.

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The paper implements a method for analyzing the stress-strain state of rectangular hollow sections (RHS) by finite-element modeling (FEM) of tests for three-point bending and torsion. Design schemes, 3-D solid-state and deformable models have been developed using the automated analysis and CAD/CAE system software, made it possible to obtain equivalent stress distributions and displacements in models. A simulation of tests for RHS with a cross section of 40 mm × 50 mm, manufactured in two ways, was carried out: (a) by direct-forming of galvanized steel strips on roll-forming mill in a semi-closed section with a longitudinal gap of 0.5 mm between the edges formed on a 40 mm web (DF-RHS); (b) similar direct-forming to the closed section and next welding the edges to a longitudinal weld along the web middle of 50 mm (DFW-RHS). RHS with various wall thicknesses (t = 1.93 mm, 1.84 mm and 0.7 mm) was investigated, given the design features that depend on the manufacturing processes of structural sections. It was found DFW-RHS is stiffer by at least 50% compared to DF-RHS, which allows to savings the metal by reducing the RHS wall thickness by 62% while maintaining the same stiffness and ensuring high strength of structural section.

The problem urgency for determining the optimal rolling and heat treatment schedules for providing the required indices of heavy plates physical and mechanical properties is shown. The use of statistical mathematical models for solving this problem is substantiated and the methodology for their design is described. Statistical mathematical models were designed using the mathematical statistics methods and Data Mining tools to determine the yield strength, ultimate tensile strength and percent elongation for 10Mn2VNb steel plates rolled under 3600 heavy plate mill conditions. Software for the numerical implementation of these statistical mathematical models has been developed. Applied software has been developed for the numerical implementation of the statistical mathematical models for predicting the heavy plate’s mechanical properties, and high calculation accuracy has been confirmed with the ones help: 95.82% for the yield strength, 96.78% for the ultimate tensile strength, and 91.48% for the percent elongation. The regularities of the influence for finish rolling factual temperature in the finishing stand of 3600 heavy plate mill and the plate thickness on 10Mn2VNb pipe steel physical and mechanical properties were identified by processing the database and using the designed software.