Materials Science Forum Vol. 1037

Abstract: The disadvantage of the known methods of hardening springs is the impossibility of their use when hardening springs of a conical shape or of a shape of a paraboloid of rotation, since they are intended only for cylindrical shape springs and are not suitable for conical shape springs or those of a shape of a paraboloid of rotation specifically because of the difference in the shape of the springs. One of the disadvantages of the known springs hardening mechanisms is the impossibility of hardening the inner surface of the conical compression springs. A new method of hardening springs is proposed, the unmatched advantage of which is the ability to create plastic deformations on the inner and outer surfaces of the spring coils compressed to contact and on the surfaces along the line of contact between the coils. A new advantageous mechanism for hardening springs is proposed, which makes it possible to harden the inner surface of compression springs having a conical shape or a paraboloid shape of rotation, in a compressed state.

Abstract: Adapter parts are common in hydraulic pipelines. They can connect pipes of different cross-sections. The article discusses the crimping of pipes. Its peculiarity is that the pipe section to be crimped undergoes thinning, which is ensured by the gap between the tools. This process was studied to determine the deformation forces and the influence of various parameters of the operation on its value.

Abstract: The article discusses the issues of chatter damping during milling. The relationship between the amplitude of forced vibrations and the cutting speed has been established. The choice of the optimal values ​​of the cutting condition during end milling is proposed to ensure the minimum vibration amplitude.

Abstract: Despite the advanced development in the field of creating new hard-alloy and ceramic tool materials, the use of modern high-speed steels has not yet lost its relevance, and it is especially true for the production of small batches of costly specialized tools, especially since modern strengthening technologies can make it competitive. For example, additive production systems associated with laser or electron beam manufacturing methods create products, including Ti-6Al-4V alloy, with low surface quality, and it is still necessary to apply the additional cutting treatment. The features of milling titanium alloy obtained by the electron beam melting method were revealed. It is determined that the force parameters differ from those in the processing of metal obtained by traditional technologies. Thus, the component of cutting tangential force F_T increases by approximately 15%. At the same time, a 20% drop in the radial force F_R observed

Abstract: The results of residual stress characterization near friction stir welded (FSW) butt joint of aluminum plates are reported. The experimental analysis employs two-side measurements of local deformation response on small hole drilling by reflection hologram interferometry. The approach developed is based on the unequivocally solution of the properly posed inverse problem thus deriving both membrane and bending residual stress components. Residual stress components of high level are derived inside the tool shoulder borders on both specimen faces.

Abstract: In this report the problem of control of solidification crack formation in welded plates is considered. In this problem the welding source is determined in dependence on the preset configuration and curvature of the rear part weld pool. A double ellipsoid model of weld pool with preset semi-axes may be used for the first approximation of preset weld pool configuration. It is an inverse problem which may be more efficiently solved as optimal control problem. The Function of welding source as a controlling function obtained in the result of solution is determined in a class of piecewise continuous functions which is more common class and the continuous-smooth functions are special partial case of common class. Recent methods of optimal control which use for solution of optimal control problems require to present the controlling functions in class of piecewise constant functions. Laser influence, electron beam, plasma, arc and submerged arc are the welding sources with high concentrated energy. A mathematical models of these welding sources may be introduced in class of piecewise continuous function with an efficient accuracy.

Abstract: This article discusses the issue of increasing the efficiency of alloying low-carbon steel during electroslag remelting with fluxes obtained on the basis of multicomponent mineral raw materials. The process of transition of an alloying element, from molten slag to metal, was investigated in various operating modes of the slag system, where the system itself experienced various degrees of hydrodynamic impact. A model is proposed and described, showing the uneven distribution of the alloying element in the metal melt. The composition and structure of the obtained alloys are investigated.

Abstract: The article investigates the effect of the strain rate on the driving force of recrystallization during hot working of the as-cast structure. For the study, we applied previously obtained experimental data of recrystallization kinetics during this stage of thermomechanical treatment. In addition, hot laboratory rolling, followed by saltpeter bath soaking, were performed in order to obtain supplemental data on grain structure size and orientations. Grain structure size was examined by optical microscopy, and its orientation was examined by X-ray texture analysis. The studies demonstrated, that overestimated recrystallization driving force not only results in erroneous kinetics estimation, but also gives excessive number of recrystallization centers and undersized grain structure. Besides, unaccounted effect of recrystallization driving force on grain size leads to distorted predictions of texture composition. In order to avoid this, it was recommended to apply an special exponential accumulated strain dependent coefficient.

Abstract: Plastic forming, in many cases, includes the drawing of hollow cylindrical products as the main operation. For the manufacture of such products, round blanks are used as semi-finished products. However, during the blank production from strips or tapes, their geometry causes a very significant metal loss. A very effective way to reduce metal loss is to replace round billets with square ones. The use of square blanks gives an additional increase in the height of the products. In this regard, the article investigates the drawing of a square blank into a cylindrical die. The research was carried out on the basis of the analysis of experimental work and computer modeling. According to the results of the research the rational ratios of the geometric dimensions of the tool and workpieces are found.

Abstract: The article discusses the technologies used in the manufacture of liquid rocket engines filter elements. The analysis of the most widely used methods in the aerospace industry for obtaining grooves and holes in metal filters is carried out, as well as progressive methods for their production are proposed. Special means of technological equipment for the fine filter elements manufacture using electroerosion treatment have been developed.