CONDITIONS OF DISCRETE CONVERGENCE OF STRUCTURES SYNTHESIS MODELS IN METAL AND NON-METALS COMPOSITIONS

The set-theoretical convergence of models of continuous and discrete synthesis processes in the compositions of metals and non-metals at the action of ray sources is shown. The non-metal density function obtained by the IDS thermal impulses on the temperature axis projection has a periodic view with fi xed stationary temperatures. They coincide with the boundaries of diff erent areas of change in the speeds of metal heating. This convergence of models to the general periodic operator is possible under four conditions of beam scanning: separation, compactness, property of states, stability. Then the current reciprocity ratios of the system (metals/non-metals) allow the use of the temperature of stationary non-metals as support for metals and serves to determine the parameters of ray sources when synthesizing structures in the compositions of the volume of the material.

Statistical modeling of temperature operating modes of heating furnaces for hot strip mills

The article provides a method of mathematical modeling to improve temperature operating modes of heating furnaces for hot strip mills. The object of the research is the thermal operation of a continuous walking beam furnace for heating slabs before rolling. The subject of the research is statistical modeling of metal heating in furnaces of this type. The creation of a statistical model consists of factors selection, construction of regression model, correlation analysis and assessment of the variables significance, adjustment of factors and obtaining regression equations. The main part of the research refers to a statistical model based on a comprehensive analysis. This model is based on the results of 15 automated industrial experiments on Russian heating furnaces of hot strip mills and describes the heating process in walking-beam furnace with acceptable accuracy. The adaptation of the statistical model and error calculation has been carried out. The article contains graphs comparing real temperatures and temperatures calculated on the basis of mathematical and statistical models for one of the experiments. The main conclusions are formulated based on the results of the research done. For the first time in metallurgical practice, a statistical model has been developed that describes the process of metal heating in a five-zone continuous furnace with eight heating subzones. Since the regression function is defined, interpreted and justified, and the assessment of the accuracy of the regression analysis meets the requirements, it can be assumed that the model and predicted values have sufficient reliability.

Review of recent developments in manufacturing lightweight multi-metal gears

This paper provides a review of recent developments in the manufacturing of lightweight multi-metal components, and in particular gears. The literature has shown that significant efforts have been made in manufacturing light gears and numerous technical challenges exist when designing for and manufacturing with dissimilar metals including challenges in heating technologies, mechanical performance, processing parameters, metal compatibility and the interface layer between adjacent materials, as well as difficulties in multi-metal simulations. Whilst the scope of multi-metal manufacturing is vast, the main concentration of this study is on the main stages of multi-metal gear production, and specifically on preform production, multi-metal heating, intermetallic bonding, and modelling of essential forming parameters. The effects of each of these methods as well as the numerous approaches studied in the literature are presented, with a recommendation being made as to a processing route that may lead to a robust multi-metal gear with minimal production line modifications to conventional steel gears.

A Performance-Enhanced Liquid Metal-Based Microheater with Parallel Ventilating Side-Channels

Gallium-based liquid metal can be used as a material for microheaters because it can be easily filled into microchannels and electrified to generate Joule heat, but the liquid metal-based microheater will suffer breakage induced by voids forming within the liquid metal when the temperature normally gets higher than 100 °C. To resolve this problem, a novel liquid metal-based microheater with parallel ventilating side-channels is presented. It consists of a liquid-metal heating channel and two parallel ventilating side-channels. The heating channel is connected with the side-channels by small gaps between polydimethylsiloxane (PDMS) posts. Experimental results show that this novel microheater can be heated up to 200 °C without damage. To explain its excellent performance, an experiment is performed to discover the development of the voids within the liquid-metal heating channel, and two reasons are put forward in this work on the basis of the experiment. Afterward pressing and bending tests are conducted to explore the mechanical stability of the novel microheaters. Finally, the microheaters are applied to warm water to show their good flexibility on non-flat surfaces. In consequence, the novel liquid metal-based microheater is believed to be widely applicable to soft micro-electro-mechanical system(MEMS) heating devices.

Mathematical Model of Metal Heating in the Continuous Walking Beam Reheating Furnace

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