Materials Science Forum Vol. 946

Abstract: The paper presents a mathematical model and the elements of a computer program for calculation and visualization of solidification of the rotating molten iron of the working layer of the roll in the centrifugal machine. We established the dynamics of changes in supply rate of carbide nanopowder feeding on the surface of the molten metal, provided its uniform distribution along the solidifying layer of the cast iron. It is shown that the working layer of the iron cools sideways and more intensively from the side of the chill mould; the areas, which are located near it, are the first to reach the solidus and liquidus temperatures. During cooling the layer of the iron, a maximum of temperatures is observed at a distance of 25 – 30 mm from the protective flux contacting surface. It was established that for a uniform distribution of nanopowder in the solidifying layer of the iron its feeding supply rate needs to be proportional to the speed of the moving the front of particle penetration, which is defined by the solidification front. Powder feeding needs to start from the time concurrent with the start of moving the front of particle penetration into the metal and to finish when an opposite crystallization front begins to form from the side of the flux.

Abstract: The influence of the electromagnetic mixing (EMM) of liquid metal in the mold of the continuous casting machine on its thermal work, the formation of the structure and properties of cast billets are investigated. The influence of the current and frequency of EMM on the mechanical properties, macro-and microstructure of round and square sorted billets was established.

Abstract: In this paper the new method of forming based on flanging is investigated. The obtained experimental results supported the theoretical conclusions and allowed us to define geometric dimensions of a blank for forming the thin axisymmetric parts with minimal thickness fluctuations. This analysis serves as a foundation for further design of the technological process.

Abstract: At present time a lot of methods are used for the assessment of product quality level, as well as its manufacturing perspectives. Only quantitative data can be used in order to compare the competitiveness of products, facilities, companies, etc. But methods for quantitative assessment of technological processes competitiveness have not been still proposed. The present paper describes a developed procedure for evaluation the competitiveness of technological processes. It takes into consideration the main factors which are used for estimation of process effectiveness: quality of products, level of applied technologies and production costs. In order to range these parameters, it is proposed to use weighting factors for each of them. An integrated efficiency index may vary within a range of 0 to 1. This method allows not only evaluating competitiveness of production processes, but also choosing the most rational production process, based on required properties of the processed item. The application of the developed approach is shown on the example of reinforcing steel manufacturing, which can be produced in different ways. The obtained results of calculation present a comparison of selected manufacturing techniques by the following parameters: strength and ductility properties of reinforcing bars, an applied forming method, possibility of a layer winding and a range of diameters of bars in coils. It is shown that the developed model makes it possible to determine a trend in development or adjustment of operating parameters for existing options of processes applied at an operating plant.

Abstract: Over the past decades the science of friction has got great development. Processes of friction and wear significantly depend on constructive junction design, selection of wear resistant materials and effective lubricants for them, as well as the conditions of the machinery operation. Currently, a large number of scientific works [7-11, 16-20] are devoted to the review of the contact interaction conditions with the use a lubricant. The method of elastohydrodynamic lubrication is of particular interest when studying different kinds of lubrication. According to the elastohydrodynamic lubrication theory, contact conditions of two elastic bodies are characterized by high pressures which cause the elastic deformation of solids and by the dependence of a lubricant viscosity from the pressure. When using the elastohydrodynamic lubrication the layer profile, the sum amount of elastic deformations, elastic deformations and the lubricant viscosity dependence from pressure are given by set equations [12-15]. The impact of elastohydrodynamic lubrication method on the surface layer of the contacting parts is of great interest.

Abstract: The technology and equipment for diesel engines steel fuel pipes cold rolling and coil drawing production on a self-aligning mandrel are considered. We presented current production line scheme for the pipes production, which includes pipe-rolling drum mills, radial forging machines, thermal furnaces with a protective atmosphere, finishing lines for unwinding coils and straightening pipes, a system of conveyors and stores for transferring coils from one unit to another. A list of articles and patents containing basic information on this topic is attached.

Abstract: The results of the process experimental studies of titanium alloys transverse rolling bars are presented. The efficiency of using such a process for reducing the surface roughness is shown. The samples were tested after rolling on corrosion-resistance resistance, ultrasonic testing, and also the study of the metal microstructure was made. For the bars transverse rolling in industrial conditions, a tooling was developed and created, intended for installation on operating centerless lathes instead of tooling with a cutting tool. Production tests of new equipment has shown its good performance.

Abstract: One of the main ways to improve product quality, obtained by forging, is implementing shear and alternating deformation (severe plastic deformation) during deformation process, which allows manufacturing products with required mechanical properties and less forging reduction. In practice, it is possible to implement shear and alternating deformation by improving the design of the ingots or the billets, forging tools, heating modes and forging method. In this paper newly designed forging die, which allows implementation of shear and alternating deformation without sufficient changes of the billet sizes, is proposed. By the research results of the new forging technology influence in the proposed tools on the microstructure evolution, it was found, that the use of the newly designed step-wedge dies has more potential for manufacturing high-quality forgings with required level of mechanical properties.

Abstract: The performed research helped to develop and implement a new process of manufacturing small high pressure cylinders, in which the operation of pressing of tubular blanks with preliminary induction heating of the deformation zone. A two-layer inductor was designed and an industrial unit for preliminary differentiated induction pre-heating for the developed technological process. The forming rate was determined, ensuring preservation of the specified temperature difference and manufacturing of deformed tube end in accordance with the requirements for its geometry. Heating die-blocks were designed for blanks deforming for application in manufacturing of diameter, allowing keeping the necessary temperature gradient at deforming. Developed technological lubricants can be used for obtaining high quality products, increase in labor protection and die-blocks durability.

Abstract: A universal geometric model of the deformation zone during rolling of a "random shape" workpiece in a two-roll groove of a "random shape" is considered in this paper. The level of simplicity of the model should provide, on the one hand, a sufficiently detailed and accurate description of the deformation zone geometry and, on the other hand, ensure the possibility of implementing "fast" algorithms for calculating the necessary characteristics of the rolling process.