Applied Mechanics and Materials Vol. 756

Abstract: Multilayer materials and materials with coatings are widely used in various applications. In studies of properties of new materials are run into poorly explored occurrences quite often. In such occurrences are among thermal diffusion (Soret effect) in solid materials. At this paper presented the model of formation of diffusion zone between two-component coating and base at the condition of heat flux action. Model completed of mechanical equilibrium problem. It was formulated the analytical solution of problem, which are applicable for concentration redistribution calculations and also for stresses and deformations in diffusion zone.

Abstract: The article is devoted to the rational consumption of energy resources when processing of blanks of machine component parts with metal-cutting tools during machine-building production. The scientific and methodological approach to the establishment of energy-efficient processing conditions is proposed, the one is based on the optimization of fabrication procedures according to new energy efficiency criterion. It was given the study of advantages and disadvantages of known methods of fabrication procedures optimization according to the criterion of the lowest specific energy intensity. New integral indicator of energy efficiency of cutting operation is formulated as a ratio of constructional material specific energy intensity to the specific energy consumption in the cutting area. The methods of determining of energy efficiency figure with taking into account the properties of processed material, the behaviors of its deformation and fracture, type of formed chippings and technological purpose of processing are offered. Optimization of machining fabrication procedures with usage of new criterion permits reduction of energy costs in the cutting area by 18-22% in comparison with applicable processing conditions.

Abstract: The information about machinability of two steel – with calcium additives and without in gundrilling are given. Experimentally determined technological characteristics of calcium steel AC41Cr4 machinability in deep hole drilling with the gun drills of diameter 2.05 mm. The results of measurement fluctuation of average diameters of holes and surface roughness are given. Microphotographs of different forms of chips after gundrilling are presented. Information about steel with calcium additives machinability was described.

Abstract: This article describes a method of determination of the parameters of the rheological material properties of nickel-chromium alloy 10H11N23T3 MR VD used in aircraft engine building, while milling. To register a component of the cutting force F_x, F_y, F_z realtime we used the dynamometer Kistler 9257V. The calculations were performed in the CAE system Deform with the use of FEM-model.

Abstract: In this paper different contact conditions between tool, chip and work material are analyzed. Experimental and theoretical studies of contact load distribution on the artificial flank wear land of the cutter in free orthogonal turning of a disk made from titanium alloy (Ti-6Al-2Mo-2Cr) are described. Investigations of cutting with various feed rate and cutting speed show that the greatest contact loads are observed immediately at the cutting edge. It is associated with the discontinuous character of titanium alloy chip and the elastic recovery of the transient (machined) surface at the moment when generated chip element is separated. The main influence of the variable chip thickness ratio of the discontinuous chip on the value of the greatest normal contact load near the cutting edge is shown that confirms the author’ hypothesis about a sag of the transient surface in the cutting edge region.Abbreviation and symbols: m/s – meter per second (cutting speed v); mm/r – millimeter per revolution (feed rate f); MPa – mega Pascal (specific contact load as stress σ or τ); h_f – the width of the flank wear land of the cutting tool, flank wear land can be natural or artificial like in this paper [mm]; x_h – distance from the cutting edge on the surface of the flank wear land [mm]; σ_h – normal specific contact load on the flank land [MPa]; τ_h – shear (tangential) specific contact load on the flank land [MPa]; HSS – high speed steel (material of cutting tool); P_{y r} – radial component of cutting force on the rake face [N]; P_z – tangential component of cutting force [N]; γ – rake angle of the cutting tool [°]; α – clearance angle of the sharp cutting tool [°]; α_h – clearance angle of the flank wear land [°]; b – width of a machined plate or disk [mm]; a – the thickness of the layer being removed (uncut chip thickness) [mm]; a₁ – chip thickness [mm]; K_a – chip thickness ratio (K_a = a₁/a) as a degree of plastic deformation in chip formation zone; K_a2 – variable chip thickness ratio, K_a2 = a₂/a₁, where а₂ – distance from the rake face surface of the chip to the contact point of two neighbouring elements of the chip [mm]; Φ – shear angle [°]; h_d – value, which determines the depth of deformation, for an ordinary task it is equal to the thickness of the machined part or the radius r of the machined disk [mm]; q – intensity of loading in the chip formation region [MPa].

Abstract: Issues of development of adaptive pulse-arc welding methods for construction and repair of the main pipelines are considered in this work. Welding methods are made on the basis of examination of smelting kinetics and transfer of some electrode metal. These methods allow ensuring a defect-free forming of root, filling and facing seams of welding combination in different space positions.

Abstract: The specifics of fracture of weld seam samples of aluminium-magnesium alloy, obtained by the friction stir welding (FSW) method at strain, have been studied. It has been shown that the weld seam contains aluminium-oxides, which are located on the surface of the conjugation of two sample parts. This imperfection leads to the effect when the initial crack spreads from the seam root over this surface of conjugation. The subsequent fracture proceeds over the basic metal of the seam.

Abstract: Existing technologies of manufacturing and operation of picks at mining machines entail high level of metal waste and result in unreasonably high economic costs of engineering and coal mining industries. It is proposed to manufacture reusable picks with a changeable working part of the head. Contrary to the common beliefs the in situ testing confirmed the feasibility of using such picks for rock breaking, as well as their high efficiency.

Abstract: The process of hollow conical forming is described for two schemes: crimp-distribution for hollow billets and stretching from sheet billet with subsequent crimping for cylindrical blank. The item thickness varying was investigated for these schemes. Dependency of technological allowance ratio on crimping coefficient and expansion ration for items allowance was investigated. The effectiveness of stretching from sheet billet with subsequent crimping was proven.

Abstract: The main thermal and morphology properties of novel thermally conductive polymeric materials are studied in this work. Novel thermally conductive materials can be used as heat-releasing materials in LED-lamps.