Abstract: A method is described to determine geometrical dimensions of electrode metal droplets depending on short circuit duration. It provides a quantitative evaluation of the electrode metal transfer and the energy impact on metal parts being welded. It is proved that using inverter power source decreases the size of droplets transferred to the welding pool by 24% in average if compared with a diode power source. It also reduces overheating of the droplets which improves efficiency of transferring chemical elements from the electrode to the weld metal.
Abstract: Investigation of the metal of exploited and damaged bends of water and steam-removing pipes by the spectral-acoustic control method and by the method of electron microscopy was carried out in the work. A sample without damages, a specimen with a corrosion-fatigue crack and a sample with a technological sunset type defect were investigated. Graphic dependencies of acoustic characteristics on the time of operating time are constructed. The values of the acoustic characteristics corresponding to the defective state for the metal of the bends of the water and steam-removing pipes have been established.
Abstract: The possibilities of using nanomaterials and nanocoatings for machine building are considered. The review of software for engineering calculations of welding processes and heat treatment is carried out. A decision support system for choosing a rational amount of nanostructured modifier powders for welding corrosion-resistant steels is proposed.
Abstract: The paper is focused on the effect of homogenous and inhomogeneous magnetic fields on crystallization, and some physical and chemical properties of silver azide (morphology, electric resistance, defect structure, reactivity) as well. The authors put forward an efficient procedure for growing crystals with specified sizes, reactivity and minimized impurities.
Abstract: It is proposed to use controlled mechanical transfer when the strip electrode of cylindrical products is deposited at an angle to the generatrix. The influence of the regime parameters on the stability of penetration of the base metal is determined. A mathematical model for calculating the configuration of the deposited layer is given. The analysis of advantages is carried out and conclusions are drawn about the prospects of the proposed technology for surfacing.
Abstract: It was experimentally established earlier that the increment of the electrode wire melting coefficient at submerged arc welding and surfacing with magnetic fields action (with equal parameters of the welding mode) depends on the chemical composition of the wires. It is suggested that this effect depends on the magnetic properties of the welding materials, i.e. electrode wire and base metal. To measure the magnetic properties of welding materials, a method has been developed in which the magnetic properties of welding materials on samples are investigated. The samples were made in the form of tori, on which the primary and secondary windings were placed. The primary circuit contains an ammeter and a voltmeter, as well as a wattmeter that allows to take into account losses in the sample on hysteresis and Foucault currents, and the secondary circuit contains a voltmeter. Experimental data on the magnetic properties of some welding and surfacing wires, as well as of base metals, are obtained. A simplified method is proposed, in which torus samples are also used, but on which only one winding is placed, over which a direct current is flowed. The value of the increment of the electrode wire melting coefficient at arc welding with the action of magnetic fields increases with increasing their magnetic permeability.
Abstract: The results of investigation of the time and power parameters influence of high-temperature synthesis under pressure on the grain structure formation and strength properties of the Ni3Al intermetallic compound are presented and discussed. Dependences of the grain size in the intermetallic compound synthesized under pressure and its strength properties on the value of the preload on the initial powder mixture (3Ni + Al) and on the delay time of pressure application to the thermoreacting system were determined from the time of initiation of intermetallic compound formation volumetric exothermic reaction.
Abstract: Polymer coatings are widely used for effective vibration damping of sheet or hull structures of different engineering systems. The article presents a calculation and experimental technique that enables improved accuracy and validity of damping properties determination of polymer coatings. Mathematical models to determine the parameters of the experimental specimen having a homogenous strain state of the polymer coating are obtained. Experimentally confirmed that the use of coatings based on adhesive compositions such as "Sprut" increases by 18...28 times the damping capability in metal structures. An addition of fillers in adhesive compositions "Sprut" type in a proportion of 30...50% of its weight reduces by 2.4 times the damping properties of metal structures.
Abstract: The up to date industry tends to introduce additive technologies in all fields of production, since their use furthers manufacturing of sufficiently qualitative products in a quite quick and economical way.As a consequence, it is still a topical issue how to control quality of the output products.The paper reports on a numerical model of thermal processes in a substrate plate and in a product while depositing.Temperature distribution patterns and a penetration form of a substrate plate are considered for the entire process of deposition.