Key Engineering Materials Vol. 844

Abstract: This research aimed to prepare (Fe-Ni) alloy by powder technology method for its technological and commercial importance. Iron and Nickel powders were tacking then their powders mixed and blended together with percent (63% Fe-37% Ni), then the powders compacted isostatic cold pressure at (6 ton). Laser surface treatment was done for the samples with different energies (0, 200, 260, 300) mJ and pulse time (10 sec) At a distance (100 cm). The X-ray diffractions test indicated that all samples have Face Center Cubic (F.C.C), and the samples at 300 mJ has best properties which include increase of phases intensity and decrease of grain size according to Debye-Scherrer equation. The Atomic Force Microscope (AFM) also shows better properties with increase laser energy. Where increased soft-ness of surface, homogeneity surface and decrease in grain size with increase laser energy. The laser analysis resulted that melting all surface molecules which led to improvement in the structural properties.

Abstract: Machining of Automobile and aerospace components are the prime concern for close tolerance and eastern mechanical design. AA7050 is the established aluminium alloy for automobile and aerospace components. AA7050/B₄C composite enhances specific strength and wear property of the alloy. The present paper aims to develop AA7050/5%B₄C Composite through flux assisted Stir casting method. Characterized its microstructure for proper distribution and incorporation of the particles. Furthermore, non-conventional machining done on the composite through CNC die-sinking EDM with process parameters Peak current (Ip), Pulse on time (Ton), and Pulse off time (Toff). The experiments are designed by Taguchi L9 orthogonal array to obtain the machining responses like Material removal rate (MRR), Surface roughness, (SR) and cutting speed (Cs). Further the responses are optimised using Taguchi analysis considering higher the better criterion for MRR and Cs and lower the better for SR. The optimal set of process parameters obtained for MRR is X3Y3Z2, for SR X3Y2Z3 and Cs X3Y3Z2. The confirmation tests conducted with optimal set of process parameters for each response. The error estimated between predicted and experimental at optimal sets is within the acceptable threshold.

Abstract: This paper reveals that obtaining high-quality sinter, improved or stabilized by its size and strength, is a challenge to be solved by embracing both the formation of sinter with the strong structure and the optimal mineralogical composition of its bonds during the preparation of the sintering blend. The existing technological schemes of iron ore sintering do not allow producing the sinter where the amounts of fines with 0-0.5 mm of fraction would be less than the typical amounts of 8.1-20.4%. Therefore, the study to establish how the blend preparation with the preliminary made composites affects the parameters of iron ore sintering process and the quality of the resulting sinter has been carried out. It has determined that the use of separate pre-granulation has commonly positive effects on the process of blend preparation, namely it significantly decreases the amount of non-granulated fraction of 0-1 mm and increases the equivalent diameter of the granules, reduces the standard deviation and variation coefficient, indicating the more homogeneous granulometric composition of raw granules.

Abstract: A large amount of finely dispersed manganese ore left after benefication operations or blown out from the furnaces is unsuitable for direct use in electric furnaces and blast furnaces, therefore it is necessary to granulate it in order to have the efficient use of its fine ore particles in metallurgy. To make our research more of practical use, we found it is reasonable not only work over manganese fines sintering but also to attempt mitigating the negative effect on the environment produced by the further sintering and apply the biofuel within the total fuel mass. Under laboratory conditions, the studies have been carried out with the objective to obtain manganese sinter, in which wood biomass is applied, namely initial and pre-pyrolyzed, at temperatures of 673, 873, 1073 and 1273 K. The amount of biofuel in the sinter blend was 25 wt.%. It has been established that the biomass use causes the decrease in the specific capacity of the sintering plant. However, for the efficient manganese ores sintering process, the biofuel of high pyrolysis temperature of 1273 K is required. To achieve the specific capacity and the yield to be as high as those when coke breeze is only used, the amount of the biofuel for manganese ore sintering should be less than 25 wt.% of the solid fuel. Additionally, it has been revealed that the further increase in the biofuel ratio in the total fuel amount is possible on condition that its reactivity is decreased, or larger particles of the biofuel are used.

Abstract: The further evidence is presented for the phenomenon existence of the electrochemical phase formation of metals and alloys through the stage of the overcooled liquid state. An idea is proposed about the possible occurrence of wave-like shapes on the surface of metal deposits, electrodepositing under weak force impact. First it was predicted and then revealed experimentally, a wave-like vibration of a solidifying surface of the metal being electrodeposited in the form of ripples or choppiness under the weak force impact in parallel to the crystallization front. A mathematical model has been obtained describing the liquid state behaviour of metals being electrodeposited under the impact of centrifugal force on the annular plate. The generalized Maxwell model was used as the basic rheological equation of a state. The difference between the results obtained is testified when considering Newtonian and non-Newtonian (power-law) liquid. The software blocks for solving the obtained mathematical model, based on the MathCAD package, have been developed.

Abstract: To obtain reliable joints in the conditions of open construction is complicated or impossible to use stationary machines and apparatuses, so requirements to welding processes are of special interest. The most interest concerning the support of strength and reliability of welded joint is specific processes developed after the crystallization of weld at weld zone. The value of the zone of thermal influence depends on the welding conditions and properties of metal that is welded. That is why the research on the influence of welding conditions on the formation of the structure of welded zone and thermal influence zone is actual.

Abstract: In this article, mathematical models and processes of introducing homogeneous ultrasonic oscillations and mechanical stresses into silicon wafers in the direction of their thickness are developed and investigated, and mathematical models of the movement of interstitial defects in silicon wafers created by the processes of ion-beam transients at the transitions of ion-beam transitions and hidden dielectric layers using the action of ultrasound oscillations and mechanical stresses, both in the process of implantation of impurities and before the annealing of plates upon activation of the impurities are developed and investigated.

Abstract: During the experimental study, a pronounced beating and sealing of the side surface of the tubular, cylindrical blanks was recorded. It is established that cracks appear and develop in the central part of the lateral surface, i.e., it are destroyed. This fact confirms the claim that the destruction of tubular, cylindrical blanks of some materials begins on the side surface. It is established that the bases of analytical dependencies between the components of deformations describe the obtained results of the experimental study of SR tubular, cylindrical blanks within the error of the experimental data, which made it possible to construct a number of mathematical models for the purpose of further study of the SDS and the method of their determination.

Abstract: Mechanical properties and texture of tube material formed in the process of tube production were studied. Texture in tubes was estimated by contractile strain ratio (CSR) according to requirements of the standard for tubes. Mechanical properties depend on CSR. Optimal values of mechanical properties were determined: ultimate strength, yield strength and relative elongation which provide CSR values within 1.3...3.5. The texture was evaluated in the process of tube manufacture. An increase in radial component of the texture leads to an increase in CSR. At high CSR values up to 3-3.5, tubes often do not withstand process tests for flattening and bending. Correction of CSR values is required. It was shown that an increase in ductility of tubes increases the value of CSR.

Abstract: The article considers issues related to the choice of abrasive material and technology of its use for the formation of necessary roughness on the base material and necessary heat resistance of the heat-protective coating during plasma spraying. The influence of the shape and size of the abrasive on final roughness of the treated surface was studied at various angles of contact between the sprayed abrasive and the surface (angle of attack). From the condition of maximum heat resistance, the composition of the heat-resistant composite coating of the spinel type was determined, which consists of 3 layers: the 1st layer (sublayer) material is a chromium-aluminum composite and the 2nd layer of a transitional spinel-based aluminum and chromium oxide + chromium-aluminum composite and the 3rd a layer of spinel based on aluminum and chromium oxides.