In automation of consumable electrode arc welding it is necessary to have a clear knowledge about the structure of system for a self-regulation of the electrode melting rate. In the given work a general structure of this system is constructed on the basis of analytical description of dynamic processes, proceeding in the welding circuit. A simple structure analysis allows easy obtaining the necessary characteristics of the self-regulation system, including accuracy in a steady mode and time of optimizing the effect of disturbances. Criteria are suggested, that allow selecting those parameters of welding processes from the admissible values, which provide the desirable quick-response of the self-regulation system. Results of comparison of quick-response estimates, obtained by using these criteria, with results of computer modeling, are given. 21 Ref., 5 Figures. K e y w o r d s : robotic arc welding, consumable electrode, structure of self-regulation system, evaluation of accuracy and quick-response of system
Поставлена задача сопоставления параметров акустической эмиссии тем изменениям структуры, которую она сопровождает. Исследованы некоторые аспекты связи между изменениями микро-и макроструктуры стали 12Х1МФ в процессе развития разрушения. Разработаны методика исследований и конструкция образца, позволяющие эффективно исследовать связи параметров АЭ с изменениями структуры материала на различных стадиях развития разрушения. Полученные при растяжении образца данные АЭ сопоставлены с результатами металлографических исследований. Показано, что параметры акустической эмиссии, возникающей при деформировании материала, могут служить достаточно эффективными характеристиками изменения микро-и макроструктуры материала на различных этапах накопления повреждений и развития разрушения. Библиогр. 15, рис. 5. К л ю ч е в ы е с л о в а : акустическая эмиссия, микро-и макроструктура стали, разрушения, металлографические исследования, накопление повреждений
Results of experimental studies of the influence of the ratio of static and dynamic stresses on limit stresses and second critical brittleness temperature of butt welded joints with a crack on 09G2 and 12GN2MFAYu steels under the conditions of room and low (to-80 °C) temperatures are analyzed. It is found that at the specified temperature the dynamic component of critical stress decreases linearly with increase of static stress. It is shown that decrease of limit stresses and increase of the second critical brittleness temperature take place at increase of the dynamic factor. Critical brittleness temperatures of welded joints of steel with higher mechanical properties are significantly lower. It is found that ignoring the dynamic stresses leads to underestimated values of limit stress and overestimated values of second critical brittleness temperature. Presented analysis of research allows a more substantiated approach to assessment of brittle fracture resistance of structural elements made from the studied materials, and determination of their safety margins. 7 Ref., 1 Table, 7 Figures.
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