Special Features of the Structure of Laser-Welded Joints of Dissimilar Alloys Based on Titanium and Aluminum

Metal Science and Heat Treatment - The structure of laser-welded joints of parts having different thicknesses fabricated from alloys based on aluminum and titanium has been studied. Results of...     

Technological possibilities of laser cladding with the help of powerful fiber lasers

Metal Science and Heat Treatment - The results of experimental studies of the process of laser cladding with scanning with the help of a 15-kW fiber laser are presented. The surface layers are...     

Remotely controlled laser welding of tube-to-tube plate joints in the manufacture of heat exchangers

The results of investigations and design studies for the introduction of advanced highly efficient welding processes to the production cycle of manufacture of heat exchanger systems are presented. The optimum parameters of remotely controlled laser welding of tube-to-tube plate joints made of stainless steel and titanium and copper alloys are determined. Specialized equipment for laser welding of the tube-to-tube plate joints is constructed.     

Microstructure and Phase Composition of Ni-Based Alloy Obtained by High-Speed Direct Laser Deposition

Phase composition and structural features of nickel-based alloy EP741 obtained by high-speed direct laser deposition were discussed in the paper. The technology of high-speed direct laser deposition has been successfully applied during the formation of samples with the various operating parameters of the experimental device. The laser power was between 450 and 1200 W, the scanning speed was 1.2 mm/s, the powder feed rate was 45 g/min, and the laser beam diameter was 1.2 mm. The structure and phase composition of the initial material and as-deposited samples were studied using optical and scanning electron microscopy, x-ray analysis and transmission electron microscopy. The investigation has shown that spherical particles of powder (EP741) can be used to form products by additive manufacturing with the presence of additional heat treatment, since almost all the as-deposited samples obtained do not contain cracks, and large volume of pores was observed only in the sample obtained with the power of 450 W. In addition, the phase composition of the as-deposited samples showed a high content of precipitating phase Ni₃(Al, Ti) in matrix, which is coherent to the solid solution based on nickel. In theory, the presence of Ni₃(Al, Ti) phase corresponds to the heat-treated nickel-base alloy obtained by standard methods of processing.     

Classification of electrical measuring equipment

Conclusions The above problems for classifying electrical measuring equipments with respect to various characteristics of transformation and of converters which form part of electrical measuring instruments, reveal the extent of diversity in the design of modern measuring instruments. It should also be noted that all the above reasoning refers only to so-called measuring transducers which affect directly the properties and characteristics of instruments. In addition to the measuring converters, modern instruments also comprise supplementary converters, for instance, in the supply circuit, which function as rectifiers, stabilizers of the supply voltage, etc., thus still further complicating the design of the instrument.Hence, it is simply impossible to classify the electrical measuring instruments by their design, or by any single characteristic which determines the design of the instrument and its properties.In designing electrical measuring instruments, it is necessary to examine (or compile) a technical specification by means of all five classification features.The problem of selecting the type of input (receiving) and output conversion follows directly from the intended use of the instrument.Sometimes the instrument's application also determines the type of the input and output transducers.Having determined the type of conversion at the input and output of the Instrument, it is necessary to select the system of the measuring input transducer. Sometimes this problem has only a single possible solution, in other instances it is necessary to choose a system for the input receiving transducer from several possible systems.Now it becomes possible to select the type of modulation and the method of conversion by weighing up such technical and economic considerations as accuracy, frequency range, speed of operation, complexity of the design, possible cost, etc.Deceased.     

Microstructure of 316L stainless steel components produced by direct laser deposition

The prospects for direct laser deposition in the manufacture of 316L austenitic stainless steel parts are assessed. The influence of the power of the laser beam and the state of the initial material on the structure and properties of the product is considered.