Materials Science Forum Vol. 946

Abstract: The stress-strain state of a plastic layer under compression by two rigid parallel rough plates under conditions of plane deformation is investigated. The hypothesis of flat sections is used. Tangential stresses are found in the part of the layer under load, as an approximate solution of the system of equations of the stress-strain state of the compressible layer. The solution is obtained in analytical form. On this basis the velocities of the points of the layer are calculated in the analytic form. The size and shape of the free surface are calculated depending on the thickness of the layer. The coefficients of this dependence are determined by recurrent relations. On this basis, an algorithm for finding the shape of a free surface is found. The computational experiments are provided and the results are compared with results obtained with FEM and ANSYS.

Abstract: In this paper, the ABAQUS is adopted to carry on numerical simulation on straightening process of R65 heavy rail. The straightening process has been simulated here using the FE package of ABAQUS. All the input data were extracted from experimental tests according to tail manufacturing. Moreover, initial camber of the rail was measured after hot rolling and cooling process.

Abstract: Modern press forging manufacture of large steel forgings is moving along the way of increasing service properties and reducing energy-power parameters. This is evidenced by a significant number of works devoted to the study of forging technology with the use of special tools allowing to implement severe plastic deformation. As a result, it is possible to improve significantly the metal structure at the same values of the forge reduction. The paper presents the results of the development and investigation of a new method of forging large steel billets with the intensification of shear deformation and with the use of standard anvils. The analysis of the stress-strain state in comparison with traditional forging scheme on an example of forging billets made of high speed steel R6М5 (State Standard GOST 19265-73) is presented. It is shown that the accumulated degree of shear deformation, as well as the uniformity of its distribution, is higher for the new method with the same reduction values. Approbation of the new method of forging on a hydraulic press was carried out for the blanks made of aluminium alloy D16 (State Standard GOST 21488-97).

Abstract: The results of the computer simulation of the tubular billet rotary piercing process are presented. The research methodology of the deformation zone geometric ratios with due regard for the tubular billet change of shape at each helical curve step was developed .The changes pattern of the helical curve step length (l_i), quotient reduction (Δr/r₀), ratio of the tubular billet radius to the contact surface width (r/b), contact surface length of the tubular billet (l₀) with a roll, depending on the feed angle (β), roll rotation frequency (N) and plug nose extension at the gorge (С_g) was established.

Abstract: In this work the developing manufacturing technology for 4mm thick plates produced of 220mm thick continuous cast slabs instead of 150mm thick slabs for mill 3200 (Metinvest Trametal SpA) is shown. The technology has been developed with the mathematical model of the rolling process. Тhe rolling technology for manufacturing of plates (4×3125×16000mm) from slabs (217×1355×780mm) has been developed. The developed technology makes it possible to reach the final rolling temperature of 826oС, which provides a good opportunity to use it for plate production in keeping with the hot, normalizing, controlled rolling technology or TMCP, and does not limit the existing grade mix. It is possible to use for production of 220mm thick slabs instead of 150mm thick slabs.

Abstract: A theoretical investigation of the influence of the profile radius of the deforming roller on the limiting degrees of deformation in the process of flow forming is performed. Analytical and graphical dependencies allowing to determine the limiting degrees of deformation are obtained depending on the ratio of the profile radius of the roller to the initial thickness of the workpiece wall. The main practical ways of using the obtained dependences are considered. The results of the theoretical study are in good agreement with the known experimental data. The developed engineering technique can be used in designing the process of flow forming of cylindrical blanks by a torus roller.

Abstract: Manufacturing of bimetallic brass-aluminum-brass strips is connected with a number of technological features. The features under consideration are cladding (welding) of the primary components, annealing of metal compositions and strain modes assignment. The purpose of the studies upon the development of bimetallic brass-aluminum-brass strips production technologies in SUSU is to analyze the modes, as well as to elaborate recommendations for the primary components thickness selection, strain modes assignment and annealing using bell-type furnace and strand-type furnace. The performed studies resulted in recommendations dealing with annealing cycles. The studies have also delivered the regression ratio between the thickness selection of primary components during the cladding operation, and the supreme total strain. A correct ratio prevents from the surface ruptures on the bimetallic brass-aluminum-brass strips surface while rolling.

Abstract: An engineering technique has been developed that makes it possible to determine the power regimes of the process of crimping a tubular billet in a conical die, taking into account the effect of deformation conditions. The influence of the geometric parameters of the workpiece and tool, the crimping coefficient and non-contact deformation on the axial stress of the crimping process is studied. The main factors influencing the limiting values ​​of the workpiece crimping factor are established. Calculations are performed for the crimping process performed on an open circuit (without stop block), taking into account the friction and hardening of the material. The obtained results are in good agreement with the known experimental data and can be used in the development of the processes of crimping of pipe billets.

Abstract: The hot deformation behavior of the Inconel alloy 625 was investigated through compression test within the temperature range of 850–1250 °C and the strain rate range of 0.1–30 s⁻¹. Physically based mathematical model involving dynamic recovery and dynamic recrystallization processes has been proposed. Mathematical model allowed to calculate technological parameters of a rolling process of the “Inconel 625” at the hot rolling mill 2300. The pilot rolling operations showed that the possibility of the “Inconel 625” production exists. But it is necessary to provide the design changes of the cooling system of the work rolls. The article addressed the cracking behavior of nickel alloys in industries such as chemical process, nuclear generation, aircraft engine production.

Abstract: This paper demonstrates the development of a technology for low-waste zero-draft hot forging of axisymmetric parts, in particular, welding neck flanges, on the basis of an expansion-extrusion deforming procedure. In this study, we carried out a process simulation by means of DEFORM 3D for a qualitative evaluation of the plastic yield. Based on the simulation results, the method was proven feasible, and we set forth the goal to prepare the process and design guidelines for further industrial application. The region of plastic deformation was determined, and a general view of the function for determining kinematic parameters was given according to A.L. Vorontsov’s procedure. The force parameters of the zero-draft hot forging process by the combined expansion-extrusion procedure were analyzed by studying the kinematic conditions of the forging. The general function for determining the force parameters was found.