Magnetoresistance of YBa2Cu3O7 in the "cold spots" model

We calculate the in-plane magnetoresistance $\Delta\rho_{xx}/\rho_{xx}$ of YBa$_2$Cu$_3$O$_7$ in a magnetic field applied perpendicular to the $CuO_2$ planes for the ``cold spots'' model. In this model, the electron relaxation time $\tau_2\propto1/T^2$ at small regions on the Fermi surface near the Brillouin zone diagonals is much longer than the relaxation time $\tau_1\propto1/T$ at the rest of the Fermi surface ($T$ is temperature). In qualitative agreement with the experiment, we find that Kohler's rule is strongly violated, but the ratio $\Delta\rho_{xx}/\rho_{xx}\tan^2\theta_H$, where $\tan\theta_H$ is the Hall angle, is approximately temperature-independent. We find the ratio is about 5.5, which is of the same order of magnitude as in the experiment.Comment: RevTeX, 4 pages, 6 figures. V.2: 2 references adde

Improved production procedure for manufacturing chromium bronze bars

A thermal deformation treatment (TDT) method is developed and implemented during production of industrial batches of chromium bronze bars, according to which aging is performed after intermediate billet drawing to a prefinishing diameter, then finishing drawing of an aged billet follows to a final diameter with a drawing factor of 1.10-1.25. Batches of bars treated by this method correspond entirely to all standard document specifications with respect to hardness and longitudinal curvature, and bars have the required marketable condition with smooth, defect-free, shiny surface typical for cold-drawn products. © 2013 Springer Science+Business Media New York

Preparation of copper electrical engineering alloy strip with high service properties

Output is organized for industrial batches of electrical engineering strip with improved service properties, i.e., copper bus bars of rectangular section (σu determination is simplified and surface quality evaluation after bend testing is improved), commutator copper-cadmium strip of trapezoidal section (hardness increased, strip camber reduced, bulges and scratches absent from basic profile), and commutator copper-silver strip (electrical conductivity increased and stable mechanical properties achieved). © 2013 Springer Science+Business Media New York

INCREASING THE HARDNESS OF COLLECTOR BANKS FROM NON-THERMAL-BROAD BRONZE

Разработан и обоснован технологический режим, испытанный на промышленных партиях коллекторных полос клиновидного сечения высотой до 100 мм из нетермоупрочняемых бронз и содержащий 3 – 5 -проходное волочение горячепрессованных заготовок при отсутствии промежуточных отжигов и с регламентацией коэффициентов вытяжки. Готовые профили с твёрдостью, существенно выше стандартной, повышают износостойкость коллектора – важнейшего узла тяговых электрических машин магистральных локомотивов.The technological regime tested on industrial batches of collector strips of wedge-shaped cross-section up to 100 mm in height from non-heat-strengthened bronze with 3 to 5 passing drawing of hot-pressed billets in the absence of intermediate annealing and with the regulation of drawing coefficients was developed and justified. Finished profiles with a hardness significantly higher than the standard increase the wear resistance of the collector - the most important unit of traction electric cars of the main railway locomotive

IMPROVE THE QUALITY OF CONTINUOUS CAST INGOTS OF COMPLEXLY-ALLOYED BRASSES AND BRONZES

Для устранения недостатков известных кристаллизаторов скольжения (КС) и повышения качества непрерывнолитых слитков сложнолегированных бронз и латуней с широким температурным интервалом кристаллизации в условиях производства реализована оригинальная конструкция КС.In order to eliminate the disadvantages of the known sliding crystallizers (SC) and to improve the quality of continuous-cast ingots of complexly-alloyed bronzes and brasses with a wide temperature range of crystallization under production conditions, there was implemented an original SC

FEATURES OF PRODUCTION AND APPLICATION OF PRODUCTS FROM BERYLLIUM BRONZ

Сплавы меди с бериллием зарекомендовали себя одними из наиболее важных и значимых в различных отраслях ввиду их уникального сочетания эксплуатационных характеристик. Положительные свойства этих сплавов наиболее полно проявляются в проволоках и прутках. Дифференцированный подход при выборе марки бронзы позволяет использовать изделия из них наиболее продуктивным образом. Схожий принцип выбора используют и зарубежные потребители. Перспективным направлением в разработке меднобериллиевых композиций является создание сплавов со сниженным содержанием бериллия и повышенным содержанием кобальта и никеля.Alloys of copper and beryllium have proven among the most important and significant in various industries due to their unique combination of performance characteristics. Positive properties of these alloys are shown most completely in wires and bars. The differentiated approach to the choice of the grade allows the use of bronze products made of them the most productive method. A similar principle is used and the choice of foreign consumers. A promising direction in the development of beryllium copper compositions is to create alloys with lower beryllium content and a high content of cobalt and nickel

Improving the durability of the dies and product quality in the production of nichrome strips

Several complicated technological problems had to be solved to develop an alternative technology for the production of nichrome strips, the new technology involving the rolling of cast ingots and drawing of the hot-rolled semifinished products. In the traditional technology, sheet is hot- and cold-rolled and then cut lengthwise to form the strips. One particularly important advance over the existing technology is the improvement made to the geometry of the drawing channel in the hard-alloy dies. This modification significantly reduces die wear, practically eliminates breakage of the strip during drawing, and substantially improves the quality of the strip's surface. © 2013 Springer Science+Business Media New York

INVESTIGATION OF PROBLEM OF OBTAINING NICKEL WIRE SEMI-SOLID STATE

В лабораторных и производственных условиях исследованы три технологические схемы получения полутвердой никелевой проволоки. Обоснованы термические и деформационные режимы обработки промежуточных заготовок и готовой проволоки, обеспечивающие выпуск промышленных партий проволоки с механическими свойствами, удовлетворяющими требования заказчика.There are investigated three technological schemes of receiving semisolid nickel wire. In laboratory and industrial conditions were justified thermal and deformation modes of treatment of intermediate billets and finished wire providing output of industrial batches of wire with mechanical properties which meets the requirements of customer

Energy-saving technology for manufacture of collector banks from non-thermal-broad bronze

An energy-saving technological regulation was developed for the production of collector strips of non-thermo-strengthened bronze by eliminating intermediate annealing and regulating the drawing coefficients. Finished profiles with a hardness, much higher than the standard, increase the wear resistance of the collector – the most important unit of traction electric cars of mainline locomotives.Разработан энергосберегающий технологический регламент производства коллекторных полос из нетермоупрочняемых бронз за счет ликвидации промежуточных отжигов и регламентации коэффициентов вытяжки. Готовые профили с твёрдостью, существенно выше стандартной, повышают износостойкость коллектора – важнейшего узла тяговых электрических машин магистральных локомотивов