bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordinate model of product basing in the technological process of assembling in mechanical engineering
Authors: Ahatov R H , Safonov M V
Published: November 2019

Nowadays, the automated assembly of a product uses its coordinate model, which is represented by the coordinates of some set of discrete points associated with this product. These points are used, for example, to control the spatial position of the product and to control the positioning of its assembly. The selection of structure and position of these discrete points is carried out after construction of the scheme of product basing is done, thus they are indirect technological bases of a product. The article suggests using discrete points connected with elements of product design as the indirect technological bases which are setting the scheme of a product basing.
Friction welding with stirring of aluminium alloys AMg-5
Authors: Balanovsky A E , Grechneva M V , Tyurin N O , Khusanov A I
Published: November 2019

The results of friction-stirring welding with stirring are presented on the example of the aluminum alloy AMg-5. The technological process on the experimental installation is briefly described. Defects arising in the process of friction stirring welding are assessed. Main stages of friction welding technological process are singled out. In the course of researches it is established that during the process the tool rotation speed and feed speed are combined in such a way that an asymmetric metal flow is obtained. Welding parameters and the size of the tool in the FSW process have a decisive influence on the total torque, which determines the need for clamping equipment and tool lifecycle. It is shown that the total torque and torque components from different parts of the tool at different welding parameters and size of the tool change slightly depending on the welding speed, but the total torque remains constant.
Conditional optimization of geometric parameters of aircraft hydraulic system elements
Authors: Demidov A I , Bobarika I O , Gusev I N
Published: November 2019

The article describes the method of selecting the optimal geometric parameters of the hydraulic system of the aircraft. The minimum weight of the system and the minimum power consumption of the power supply are chosen as the optimal criteria. There is a mathematical model providing effective flow distribution in any branched hydraulic system. Target functions and all equations are obtained in general form.
Experimental research of cutting forces at finishing processing of machine components by elastic polymer-abrasive circles
Authors: Dimov Yu V , Podashev D B
Published: November 2019

This article presents the results of experimental studies of forces arising from the interaction of elastic polymer-abrasive wheel with the treated surface. The dependences of normal and tangential components of cutting force on the speed, tool deformation and feed are established. Cutting forces directly influence the removal rate, roughness of the processed surface, temperature in the cutting zone and residual stresses in the surface layer.
Methodology of the formalized approach of the automated construction of the manufacturing route of a mechanical engineering product
Authors: Govorkov A S , Fokin I V , Lavrentyeva M V , Karlina Yu I
Published: November 2019

The research refers to the field of automation of technological preparation of production in mechanical engineering. There is a concept of technological operations selection at manufacturing of a standard component of an airframe of an airplane glider on the basis an image of a product and objects’ classifiers of an industrial environment. Presentation of the objects of the production environment and their communication are performed in the presented theoretical and multiplicity model. The development of technological processes is considered; 3D models of the part are used in the process of TP design. The concept of the technique of automated construction of the manufacturing route on the basis of dependencies between the objects of the production environment “KE-TO-STO-Equipment” is presented.
Perspective development of diagnostic systems of aircraft structures and units
Authors: Gushchin S V , Polonsky A P
Published: November 2019

The article deals with information-diagnostic systems of detection of defects and malfunctions as applied to aircraft structures and units. Methods. Analysis of modern methods of nondestructive testing is carried out. It is suggested to use the combined diagnostics of aircraft structures and systems with the use of vibrometry in combination with the determination of the appearance of metal particles in the oil, their quantity and size. The possibility of using acoustic emission is considered. Results. The article compares the accuracy and reliability of the inspection of aircraft parts, assemblies and systems by different methods. Conclusion. We have drawn conclusions about the prospects of the proposed method of diagnostics. It is shown that trained neural networks are able to provide information about the presence of defects, their size and location when working in the software of information-diagnostic systems.
Development of the mathematical model of dynamic interaction in the vibrating technological equipment
Authors: Kuznetzov N K , Eliseev A V , Eliseev S. V.
Published: November 2019

The article is devoted to the topical problem of choosing the main parameters of vibrating technological machines used in many technological processes, including the aviation industry. It is shown that the solution of this problem is complicated by the need to create a spatial structure of the vibrating field, which is found, for example, in the vibrating devices designed for oriented placement of rivets in the container (perforated glass) before anodizing, by reporting the last simultaneous vibrations in the vertical and horizontal planes. For the solution of this and similar problems the article offers the method of construction of the mathematical models reflecting features of dynamic interaction of a working environment with vibrating surfaces of technological machines, allowing to choose parameters of a vibrating field by means of structural mathematical modeling.
Development of a computer aided design system for assembly equipment of MC-21 aircraft
Authors: Lavrentieva M V , Chimitov P E , Govorkov A S
Published: November 2019

The article considers how to use computer-aided design systems in modern “digital production” for the development of standard elements of assembly devices for the assembly of components of MS-21 aircraft. It describes the initial data and the most significant factors determining the architecture of the developed system. An example of an assembly device frame describes a software algorithm capable of replacing the designer’s work.
Development of digital manufacturing technologies for frame and casing parts
Authors: Pashkov A E , Yu Malashchenko A , Pashkov A A , Bogdanov K V , Kryuchkin A V
Published: November 2019

The purpose of the study is to develop basic approaches to digital models of cross-cutting production of frame and casing parts in order to forecast stress-strain behavior and change of a part form at all production stages. The proposed method covers stage-by-stage modeling of part production including machining, shaping (levelling) and face hardening using mechanical characteristics of a material, technological residual stress and initial shape. This approach in combination with equipment under control will allow optimizing machining conditions and achieving the required accuracy of parts and maximum capacity without pilot-scale works. The use of developed technique will make it possible to increase the production efficiency of parts due to time minimization of finishing operations and cost reduction for preproduction for the launch of new products.
Mechanization of forming and levelling of frame and casing parts
Authors: Pashkov A E , Makaruk A A
Published: November 2019

The machining of parts reinforced with ribs may lead to deformations expressed by two-axis bending and twisting. An effective method to eliminate such deviations is rolling, which unlike pressing, excludes cracking of aluminum alloys [1-3]. The developed set of manual rolling tool allows processing ribs and blades of a part to receive deformation in two planes. The development of levelling technology that includes mechanized rolling unit and software for automated calculation of process parameters of rolling seems quite promising.
Service life testing of composite material
Authors: Sturov A A , Chashhin N S , Ivanov Y N
Published: November 2019

The study aims to determine the effect of a “delamination” defect on the service life of carbon fiber reinforced polymer (CFRP) specimens and specimens that have been repaired. The tests were performed using an EHF-EV101K2-04N-1E universal testing machine, and ultrasonic flaw detection was carried out using the ELISA GMIUC002-14 complex. In the study, loading ranges were selected for cyclic tests performed for defect-free, defective and repaired specimens. The tests revealed the effect of the defect and its repair on durability of CFRP products.
Control of self-excited vibrations in face milling with two-rim mill
Authors: Svinin V M , Astakhov D M
Published: November 2019

The paper provides an overview of self-excited vibration damping methods for face milling. The main source to maintain and develop self-excited vibrations is the mechanism of their regeneration. To suppress it, two methods are currently actively used: tools with variable tooth pitch and cutting speed modulation. A combination of these methods was used to develop a vibration-resistant face mill with two-rims provided with alternating teeth and connected with adjustable stiffness by spring. The spring also allows a variable pitch of adjacent teeth to be adjusted. During cutter operation, the elastic connection of the rims creates difference in the cutting speed of adjacent teeth, which suppresses regeneration of self-excited vibrations and decreases their amplitude. The self-excited vibration damping efficiency of the proposed mill was determined by comparing its operation with that of a conventional mill in the same conditions of roughing a steel workpiece. The dynamics of the milling machine technological system during operation of both tools was studied using a simulation method. It was found that the conventional mill cannot be used under cutting conditions accepted in the study because of increased vibrations of the technological system elements. On the contrary, a two-rim mill provides almost quiescent processing conditions at appropriate values of the elastic connection stiffness of rims and their relative angular displacement. The settings of the two-rim mill were determined with respect to a moving rim and a spindle with another rim as a dual-mass system with two degrees of freedom.
About the partnership between the United Aircraft Corporation (UAC) “Irkut” and university researchers for creating high-tech aircraft production
Authors: Veprev A A
Published: November 2019

The article describes the experience of partnership between the Irkutsk National Research Technical University and the Irkutsk Aviation Plant, a branch of PJSC Scientific production Corporation “Irkut”. Here are presented the results of the joint implementation of complex projects aimed at creating a number of high-tech industrial technologies throughout the entire cycle of manufacturing aircraft products in accordance with the Order of the Government of the Russian Federation of April 9, 2010 No. 219. This study presents the solutions that are ready for copying in such areas as machine processing, metal-cutting tools production, forming and setting, surface hardening, non-destructive testing, assembling and connecting, and technological production planning.
Improving the quality of aircraft fasteners by transverse running with flat plates
Authors: Zaides S A , Kh Kuang L
Published: November 2019

For the strain hardening of aircraft fasteners, a surface plastic deformation method is proposed, based on running of blanks with smooth plates. The method allows processing parts that do not have center holes. Transverse running also eliminates the bending of the workpiece from the transverse loading forces action. Analytical dependences are obtained for determining the maximum possible contact area and relative compression for a transverse running. The quality of fasteners after transverse running with smooth plates provides the following favorable changes in the surface layer of metal: the formation of residual compressive stresses in the surface layers, a significant decrease in the initial roughness, an increase in the microhardness of the surface layer, the formation of a fine-grained structure, and the high accuracy of the machined parts diameter.
The effect of cast structures on texture and mechanical properties of AISI 433 ferritic stainless steel
Authors: Maumela M , Stumpf W E , Siyasiya C W
Published: November 2019

The influence of the individual equiaxed and columnar cast structure on the evolution of texture during thermo-mechanical processes (TMP) was investigated using the electron backscatter diffraction (EBSD) technique. The recrystallization texture after cold working and annealing was then related to mechanical properties of the initial cast structures. It was found that the initial equiaxed cast structure exhibited a homogenous γ-fiber texture while the columnar developed an inhomogeneous texture with the predominance of both the Goss and α-fiber textures. While texture has a significant influence on surface smoothness of the drawn product, it was found that it did not significantly affect the yield strength and ultimate tensile strength (UTS), but marginally affected the elongation i.e. it was found to be slighted higher for the equiaxed than the columnar cast structure measured parallel to the rolling direction (RD).
Effect of the quench temperature on the mechanical properties of a medium C Mn high Si steel during Q&P heat treatment process
Authors: Kurup V , Siyasiya C W , Mostert R J
Published: November 2019

A steel of composition Fe-0.2C-3Mn-2Si-0.5Al was fully austenized followed by a quench and partitioning heat treatment process (Q&P). The quench temperature was varied, which resulted in different volume fractions of retained austenite (RA) and martensite. Analysis of the phase evolution and the resulting microstructures during the Q&P process were carried out using different techniques namely, - dilatometry, FEG SEM, EBSD, and neutron diffraction. Mechanical properties were evaluated by standard tensile tests on samples quenched to different temperatures. The partitioning process was evaluated by dilatometry. The volume fraction of the RA was determined by neutron diffraction. It was found that the volume fraction of RA increased with an increase in the quench temperature contrary to the Speer model. It was also observed that the presence of bainite, which formed during the quench and partitioning temperature significantly stabilized the RA by carbon partitioning. The tensile test results indicated the optimum quench temperature for the best combination of strength and ductility and contrary to expectation, this did not occur in the specimen with the maximum amount of RA. In other words, the mechanical properties of the steel undergoing a Q&P process is influenced by the quench temperatures and is also affected the phase evolution which occurs during both the quench and partitioning process.
Major determinant of service life in magnesia-graphite slagline refractory lining in secondary steelmaking ladle furnace
Authors: Otunniyi I O , Theko Z V , Mokoena B L E , Maramba B
Published: November 2019

Magnesia-carbon (MgO-C) refractory bricks are used for slagline lining in secondary steelmaking to withstand the harsh basic slag and high temperature environment. In an operation using bottom purging ladle furnaces, preliminary study of residual bricks after lining failures shows less than 50 vol. % of the MgO-C bricks is typically used before the linings would fail. Slag basicity, high temperature oxidation and erosion are known as root causes of different degradation modes in this application. This work, presented in part herein, seeks to identify the dominant cause for this resource utilization inefficiency. Slag basicity excursions and thermal fluctuations versus service lives and residual thicknesses of each MgO-C brick after lining failure, were studied for five ladle linings. Optical and electron microscopy were also used in further post-mortem of the residual bricks. The operation data that showed thermal spikes above 1600 °C and acidic slags with basicity usually below the ideal of 1.67. Micrographs from the slag-refractory interfaces indicated effect of this operational extremes showing thermal shock cracking, slag penetration and evolution of phase due to the slag-refractory interactions. However, bricks evidencing these effects were not the most worn. Slag basicity attack and high temperature oxidations are diffusion controlled and did not proceed aggressively by themselves. Rather, least residual thicknesses were found in bricks from columns adjacent to the two purging gas entry points at the bottom of the ladle. Up to 86 % wear were obtained at such points, in contrast to 24 % for bricks farthest from this effect. Turbulence from the purging gas is thus responsible for localized and highest lining consumption rate that decimates lining life in these ladles. Without this purging turbulence, such as in induction stirring, it can be projected that the lining life can triple, with obvious economics and environmental advantages. While the MgO-C refractory is well able to withstand the chemical and thermal extremes of secondary steelmaking slag environment, bottom purging ladle furnace design deserves a review to improve refractory utilization.
Effect of intercritical annealing of normalised Nb-Ti-V microalloyed plate steel on microstructural evolution
Authors: Kambilinya PI , Siyasiya CW , Banks KM , Mostert RJ
Published: November 2019

A homogeneous microstructure is required for consistent mechanical properties in normalised Nb-Ti-V microalloyed plate steels. Frequently, as-hot rolled microalloyed plate steels have a banded microstructure that is persistent even after normalising heat treatment (NHT), and this leads to inconsistencies and some scatter in mechanical properties. Therefore, this work focused on the influence of single-cycle normalising heat treatment (SNHT), double-cycle normalising heat treatment (DNHT) followed by intercritical annealing normalising heat treatment (INHT) on the homogenisation and mitigation of a banded microstructure. The study was conducted on a 0.13C-Nb-Ti-V plate steel grade. The as-hot rolled microstructure was banded and had a 1.13 Anisotropy Index (AI) value. Results from the three thermal cycles revealed that the DNHT and INHT mitigated the pearlite microstructural banding and gave a more homogenized pearlite phase distribution throughout the microstructure, unlike the SNHT that retained the banding. The DNHT also exhibited the finest ferrite grain size, while the INHT exhibited the coarsest. From Vickers hardness measurements (153±5.8 HV, 157±3.6 HV and 166±4.5 HV), the UTS was approximately deduced as, 480, 490 and 530 MPa for the SNHT, DNHT and INHT respectively.
Development of lining materials for reactor vessel used in the CSIR titanium process
Authors: Sehoana M P , Fazluddin S
Published: November 2019

The CSIR Titanium powder process is a high temperature’ molten salt/alkali metal titanium production process. The aim of this process is to produce titanium powder of high purity and quality that meets the specifications for commercially-pure powder. The quality of CSIR Ti-powder produced to date shows in general that there are challenges when it comes to meeting this requirement. Two of the main challenges is the reagents used employed in the process and by-products formed which are highly corrosive. These corrosive agents promote corrosion of the reactor with the corrosion product then being introduced as impurities in the titanium powder. A project to investigate lining materials to protect the vessel from corrosion and preserve product quality and purity was thus initiated. This article gives an in-depth insight into the corrosion resistance properties of different metals that can be investigated as a potential lining material in molten lithium and molten lithium chloride environment.
EBSD characterisation of the B2 orientation in γ-TiAl based alloy
Authors: Mathabathe M N , Bolokang A S , Govender G , Siyasiya C W , Mostert R J
Published: November 2019

Electron backscattered diffraction (EBSD) has been conducted to determine the orientation relationship of the remnant B2 phase in an α-solidified γ-Ti-45Al-2Nb-0.3Si (at. %) based intermetallic alloy. The morphology and microstructural characterisation was investigated using conventional methods. The results showed that the B2-grains exhibits a Blackburn orientation relationship (BOR) with the α2 grains viz. {111}B2 // {0001}α2 and {110}B2 // {11-20}α2. Moreover, mis-orientation axes of B2-grains were found in the clusters between <101> and <111> in 57-63° angles, in the Y0 directions. In addition, it was also observed that the overall B2 grains in the alloy structure was textured and comprised of high angle boundaries of misorientations above 15° angles.
Microstructure characterisation and microhardness of P92 steel heat treated at the transformation temperatures
Authors: Obiko J , Chown L H , Whitefield D J
Published: November 2019

Modern power plant components for the transport of superheated steam are manufactured from creep resistant steels, such as ASTM grade P92, that have microstructural stability and excellent mechanical properties at high temperature and pressure. Before application as pipes, tubes and connectors, P92 steel undergoes a heat treatment of austenitisation and tempering to achieve a tempered martensite microstructure, with carbides along the prior austenite grain boundaries and carbonitrides within the matrix. In the power plant, pipes and tubes are joined by welding, inducing residual stresses and inhomogeneous microstructures in the weld joint, which reduce creep resistance. As in most steels, the temperature gradient from the fusion line to the base metal leads to different microstructural zones in the weld joint. The fine-grained heat affected zone (FGHAZ), which forms at temperatures near the transformation region, acts as a weak zone for Type IV cracking during creep. The lower and upper critical transformation temperatures for the P92 steel in this work are 800°C-850°C (Ae1) and 900°C-950°C (Ae3) respectively. As-received samples were heated to temperatures of 830, 850, 900°C to simulate the fine grain heat affected zone, or the very high temperature of 1200°C to simulate the coarse grain heat affected zone (CGHAZ), held at that temperature for 90 minutes and then tempered at 730°C to 780°C for 120 minutes. The microstructures before and after heat treatment were observed by scanning electron microscopy and optical microscopy, and Vickers microhardness measurements were done. After tempering, coarse carbides were seen on the prior austenite grain boundaries (PAGBs) and nitrides were observed in the matrix. In general, the hardness increased with an increase in the austenitisation and tempering temperature combination.
Effect of Temperature on Densification, Microstructural Evolution and Mechanical Properties of Ti-5Al-1Mo Developed via Spark Plasma Sintering
Authors: Jeje S O , Shongwe M B , Maledi N , Rominiyi A L , Babalola B J , Lepele P F
Published: November 2019

Titanium alloys are ideally suited for advanced aerospace structures and industrial applications because of the combination of high strength, low density, good toughness, stiffness, and good corrosion resistance at cryogenic to elevated temperatures. This paper investigates the effect of temperature on alloy densification, microstructure evolution and mechanical properties of Ti-5Al-1Mo processed by Spark Plasma Sintering (SPS). Ti, Al, Mo elemental powders with 94, 5 and 1 wt.% respectively were mixed thoroughly for 8 hrs to attain homogeneity. The mixed powders were consolidated at sintering temperature of 800°C, 1000 °C, 1100 °C, pressure of 50 MPa, holding time of 10 min, and sintering rate of 100 °C/min. The compacted samples were characterised using scanning electron microscopy (SEM), equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometry techniques. Compacts hardness was also investigated using Vickers micro-hardness tester. Almost fully densified compacts were obtained for samples sintered at 1000 °C and 1100 °C, the microstructures show that the sintered compacts are chemically homogeneous with the Al fully diffused into the CP-Ti matrix. The microhardness increases with increasing temperature with the maximum value being 290.35 HV.
Effect of particle size distribution on green properties and sintering of Ti-6Al-4V
Authors: Ramabulana K , Tambani M , Machio C , Makhatha M E
Published: November 2019

In this study, the conventional powder metallurgy route of pressing and sintering was employed to study the effects of the particle size of blended elemental Ti-6Al-4V powders on the properties of powder mixtures, green and sintered densities. The -45 μm and -150 μm 60Al-40V master alloy powder were blended with the titanium powder to produce the -45 μm and -150 μm Ti-6Al-4V blend. Powders were pressed at 580 to 870 MPa and sintered in a tube furnace. Taguchi method was used to optimise the sintering parameters, temperature and time, and ANOVA was employed to determine the significant parameters and their contribution to the sintered density. The optimum parameters maximising the density were found to be sintering temperature of 1300 °C and sintering time of 180 mins, for both particle sizes. The green density was higher for the coarser powder and the sintered density was higher for the finer powder.
Biocompatibility Study of Ti-based Alloys Fabricated by Spark Plasma Sintering
Authors: Mahundla M R , Matizamhuka W R , Machaka R , Yamamoto A , Shongwe M B
Published: November 2019

Titanium (Ti) alloys often find their way in orthopaedic applications owing to their superior mechanical properties, biocompatibility, corrosion resistance and low Young’s modulus. Nano/sub-micron grain structured commercially pure titanium (CP Ti), Ti-6Al-4V (Ti-64) and Ti-34Nb-25Zr (TNZ) alloys were fabricated via mechanical alloying (MA) of elemental powders followed by spark-plasma sintering (SPS). The powders were milled at 500rpm for 5h and sintered at a temperature of 1200°C, heating rate of 100°C/min, dwelling time of 10min and a pressure of 50MPa. The sintered samples were metallographically prepared to a mirror finish surface in 5:2 ratio of colloidal silica and hydrogen peroxide (H2O2) mixture. Biocompatibility tests were conducted by water soluble tetrazolium and 1-methoxy phenazinium methylsufate (WST-1 PMS) with sarcoma osteogenetic-2 (SaOS-2) human cell line. High cell proliferation on Ti and Ti-64 was observed after 1 and 4 days of incubation. After 7 days, proliferation on Ti-64 was the highest followed by Ti. However, TNZ alloy have less cell proliferation through the entire period of incubation.

Fibronectin adsorption is less for Ti and TNZ compared to and Ti-64. In decreasing order albumin adsorption was highest on Ti than TNZ alloy followed by less adsorption on Ti-64. Surface wettability of Ti and Ti-64 showed a high contact angle of between 93-98° compared to 86° TNZ alloy. The surface wettability results correlated well to less fibronectin adsorption on Ti-34Nb-25Zr alloy and highest for Ti-6Al-4V. The Ti-34Nb-25Zr showed less cell proliferation which is believed to be linked with fibronectin adsorption results.
Development of a biocompatible Ti-Nb alloy for orthopaedic applications
Authors: Fikeni L , Annan K A , Seerane M , Mutombo K , Machaka R
Published: November 2019

Metallic biomedical implants such as titanium-based alloys are very useful for orthopaedic applications due to their excellent properties which responds to changes in temperature and other conditions. However, biological toxicity due to alloying elements and relatively high Young’s modulus or mechanical incompatibilities of previously used Ti alloys have necessitated the development of biocompatible alloys with compatible mechanical properties such as beta-titanium alloys. This study aims at production of beta-titanium alloy with enhanced properties by varying milling speeds. Ti and Nb powders were mechanically alloyed using the high energy ball-mill Zoz-Simoloyer® to produce Ti-7Nb alloys by varying the milling speed. The milling process produced irregular shaped powders with increasing particles sizes as the milling speed increased due to fragmentation and cold welding during agglomeration. The mechanical alloying process had good yield. The predominant phases of the inhomogeneously milled alloy were alpha and beta phases.
Influence of spark plasma sintering temperature on the densification and micro-hardness behaviour of Ni-Cr-Al alloy
Authors: Babalola B J , Shongwe M B , Jeje S O , Rominiyi A L , Ayodele O O , Olubambi P A
Published: November 2019

Sintering temperature is essential towards attaining desired densification and formation of phases which in turn influences the microstructure and properties of a material. In this study, the densification and microhardness behaviour of Ni-Cr-Al alloy prepared by spark plasma sintering (SPS) at different sintering temperatures were investigated. After sintering operation, the density, hardness, phase analysis, and microstructural evolution were investigated using the Archimede’s principle, hardness tester, X-ray diffraction (XRD), and scanning electron microscopy (SEM) respectively. The nickel based alloy was sintered at temperatures of 600, 750, 950 and 1100 °C. The results indicated that the densification, microstructure, and hardness values were influenced by changes in the sintering temperature. The relative density increased from 73.89 % at 600 °C to 99.89 % at 1100 °C, while the hardness value was enhanced from 131.9 ± 2.8 HV to 404 ± 1.2 HV respectively.
Plasma dissociation of monazite
Authors: Bissett H , Makhofane M M , van der Merwe R , Lotter S J
Published: November 2019

Monazite is a phosphate mineral which contains a significant amount of rare earth elements (REE) with thorium (Th) and a low concentration of uranium (U). The radioactive components of monazite, Th and U, make it an unattractive source of REE due to the added cost associated with radioactive waste handling. The mineral is also chemically inert requiring the use of corrosive reagents at elevated temperatures to effectively extract REEs. According to thermodynamic calculations, monazite dissociation into oxides of REE and phosphorus (P) is favourable at temperatures greater than 1000°C, while the reverse reaction occurs well below a 1000°C. Rapid cooling is required to prevent the reverse reaction. Achieving these high temperatures, with rapid heating and cooling, is possible by means of thermal plasma treatment such as a radio frequency plasma. This type of plasma system offers superior control of plasma/particle interaction, quenching rates and plasma gas composition. The objective of this study was to determine the parameters for dissociation of the monazite under various conditions to reduce its chemical inertness. Dark and grey powders were obtained under reducing conditions, while lighter powder formed in the presence of an oxygen plasma with increase particle circularity observed after plasma treatment. While SEM-EDS analysis indicated no notable change in powder composition after plasma treatment, dissolution tests proved that monazite was not only more reactive, but also more susceptible chemical reaction after treatment.
First principle study of HF molecule adsorption on TiO2 (110) surface
Authors: Tshwane D M , Modiba R , Chauke H R , Govender G , Ngoepe P E
Published: November 2019

Titanium and its alloy components are one of the most important technological materials, which has found extensive application in various industries. However, surface defects play a key role in the mechanical properties of these components. Currently, wet chemical etching is one of the most important procedure for surface processing due to the presence of HF since it can etch metal oxide. Therefore, there still a need to investigate the etching mechanism. In this work, adsorption of HF on TiO2(110) surface has been studied using density functional theory to investigate the fundamental process of etching. HF molecule is adsorbed on the TiO2 surface by dissociation to form Ti-F and O-H species. The interaction between HF and TiO2surface become more favorable at high HF coverage. The pre-adsorbed of water molecule is favorable for HF adsorption process, which is in good agreement with experimental results. Fluorination processes show the formation and desorption of water intermediate at 0.50 ML coverage. We also investigated the relation between the work function and Mulliken charge for HF adsorption. The results indicate that the interaction of F on the surface attracts electrons due to its higher electronegativity than oxygen. Our results suggest that adsorption of HF is considered chemisorption process.
Pillared interlayered clays as catalyst for wastewater treatment: Cost-effective and sustainable materials
Authors: Baloyi S J , Seadira T W P , Ntho T A
Published: November 2019

Metal oxide pillared interlayered clays (PILC) represent a novel class of materials that have attracted interests in catalytic oxidative removal of organic pollutants in wastewater. In this work, South African bentonite clay were modified by polymeric Al/Fe, Al/Zr and Al/Cr species, and the obtained pillared solids were characterized and as potential catalysts in catalytic wet air oxidation (CWAO) of phenol in aqueous solution. The placement of metal oxide pillars between bentonite clay sheets modifies their physicochemical properties (surface area and basal spacing) and catalytic activity. The Al/Zr pillared clay exhibited a higher activity compared to Al/Fe and Al/Cr for phenol oxidation. All the pillared clay catalysts allowed the total oxidation of phenol and significant removal for the total organic carbon. The metal leaching was very low in all catalysts studied.
Solar photocatalytic hydrogen production from glycerol reforming using ternary Cu/THS/Graphene
Authors: Seadira T W P , Baloyi S J , Masuku C M , Scurrell M S
Published: November 2019

A ternary Cu/THS/rGO photocatalyst was prepared using solvothermal method. Firstly, pure anatase T1O2 hollow spheres (THS) were prepared via hydrothermal method using titanium butoxide, ethanol, ammonium sulphate, and urea via hydrothermal method. The copper (Cu) nanoparticles were subsequently loaded on the surface of the THS by wet impregnation. During the solvothermal process, the deposition and well dispersion of Cu/THS composites onto the graphene oxide surface. Subsequently, the reduction of graphene oxide to graphene was achieved. The morphological and structural properties of the prepared samples were characterized by Scanning Electron Microscope (SEM), UV-vis DRS, and photoluminescence (PL). The activities of the prepared catalysts were tested for hydrogen production via simultaneous photocatalytic water-splitting and glycerol reforming under visible light irradiation. The excellent photocatalytic activity of the Cu/THS/rGO catalyst was attributed the rGO which acts as both storage and transferor of electrons generated at the Cu and TiO2 heterojunction, thus increasing the electro-hole pairs separation. Furthermore, the effects of reaction parameters photocatalytic hydrogen production were also studied.
Effects of alkalis and zinc on the damage of the tuyere composite brick of a blast furnace
Authors: Niu Q , Cheng S S , Xu W X , Niu W J , Mei Y G
Published: November 2019

The distribution of foreign elements and its true mineral forms in the tuyere composite brick extracted from a 2800 m3 industrial blast furnace were examined to gain a better understanding of the damage mechanism of the brick. The X-ray diffraction (XRD) and the scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were applied to characterize the brick. The results show that the potassium is easier to permeate into the brick than zinc. The potassium is prone to react with Al-Si compounds in the brick to form kalsilite or leucite while the zinc is apt to react with the corundum in the brick to produce zinc-aluminum spinel. In addition, the zinc can interact with the blast furnace gas to form zinc oxide and zinc sulfide filled in the cracks of the brick. The mineral phases of the residual brick change from the original corundum and mullite to corundum, gahnite, zincite, sphalerite, kalsilite and leucite. The main cause of the damage of the brick is found to be potassium and zinc attack. In the case of degradation of the raw materials, it can choose the micro corundum brick instead of the corundum-mullite or mullite brick to prolong the life of the tuyere composite brick.
Modelling and validation of fluid flow inside a dissipative ladle shroud and a continuous casting tundish
Authors: Zhang J , Liu Q , Xin Z , Lu B , Zhang J , Li J
Published: November 2019

Fluid flow plays a significant role in the continuous casting of molten steel. In this paper, two Reynolds Averaged Naiver-Stokes (RANS) models and a Large Eddy Simulation (LES) model were comparatively employed to characterize the fluid flow inside a dissipative ladle shroud and a tundish. LES model was proved to be powerful to characterize the turbulence structure inside the ladle shroud. The effect of meshing density on the computational accuracy was considered using the LES model. The fine-mesh model can capture multiscale vortices inside the ladle shroud; while, the coarse-mesh model disables the LES to obtain the detailed flow information. The experiment of particle image velocimetry (PIV) was used to verify the flow field obtained by the LES model inside the tundish. The PIV and the LES results agree well in terms of flow pattern and velocity vector.
Effect of two-step austempering process on carbidic ductile iron
Authors: Dakre V , Likhite A , Pathak S U , Peshwe D R
Published: November 2019

The two-step austempering process when applied to ductile iron, results in significant improvement in mechanical properties due to the strengthening of the ausferitic matrix. The present work was undertaken to investigate the effect of the two-step austempering process on carbidic ductile iron. Carbidic ductile iron is a new member to the ductile iron family, it is produced by alloying the ductile iron composition with chromium. In the present work, the carbidic ductile iron thus produced, was austempered by both conventional and two-step austempering route. For both processes, all specimens were austenitized at 975°C and soaked for 180 min. In the conventional process, the specimanwas quenched in salt bath held at to 350°C, 400°C, and 450°C and soaked at respective temperatures for 180 min. Whereas, in the two-step austempering process, specimenwere first quenched in salt bath heldat 250°C. After stabilization at 250°C, the salt bath temperature was raised to 350°C, 400°C, and 450°C. After the respective temperature was attained, the specimens were soaked for 180 min. The austempered samples obtained by both processes were analyzed with the help of SEM, XRD, and TEM. Two-step process resulted in finer ausferitic matrix than the conventional process. The XRD analysis revealed an increase in carbon content of austenite and volume fraction of Carbon Stabilized Austenite (CSA) in sample austempered by a two-step process. The TEM analysis indicated that the lath width of austenite and ferrite was small in samples austempered by two-step process than the conventional process, due to a high degree of super-cooling.
Ceria doped TiO2 as photocatalyst for water treatment under visible light
Authors: Ndabankulu V O , Maddila S , Jonnalagadda S B
Published: November 2019

The photocatalytic activity of bare titania and ceria supported mesoporous titania (CeO2/TiO2) catalysts were assessed for the degradation of caffeine by visible light irradiation in absence of the oxidants. Different wt% metal loaded (bare, 0.1, 0.5 and 1.0) materials were synthesised by a sol-gel method using anionic surfactants. Various instrumentation techniques were used to characterise the prepared photo-catalysts such as P-XRD, BET, TEM, SEM-EDX, FT-IR, Raman, UV-DRS and photoluminescence spectroscopy. 0.5% CeO2 doped titania exhibited excellent efficiency in photo degradation of caffeine in aqueous solution relative to all the other prepared heterogeneous catalysts. All the materials showed good efficiency and were recyclable without loss of catalytic activity up to three times. Analysis of degradation products was carried by Liquid chromatograph-mass spectrometry. Two reaction products 6-amino-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetradropymidin-5-ly)-methylcarbamic acid (ATCA) and N-methyl-N-(methylcarbomoyl)-2-oxoacetamide (MMO) were positively identified.
Application of TRIZ theory in steel rolling production
Authors: Li J B
Published: November 2019

In the face of two problems encountered in the process of steel rolling production, the TRIZ theory was applied to analyse and solve the problems, and unprecedented solutions were put forward, both of which were applied for patents and authorized and published. It is expected that through this paper, innovative thinking will be stimulated and the problems encountered in iron and steel production can be solved quickly.
Analysis of the mechanical properties of Q345R steel in deep-regulating units by the spherical indentation method
Authors: Sun M C , Yang C , Xiao S Y , Tan W , Zhou G P
Published: November 2019

The principles of testing the mechanical properties of metallic materials through the use of the spherical indentation test have been analysed and studied in this paper. The error between the representative indentation stress from spherical indentation and the theoretical stress of the power exponential equation was taken as the convergence condition using the optimization function in Matlab. The yield strength, strain hardening index and elastic modulus were optimized between the stress-strain curve from spherical indentation and the theoretical stress-strain curve of the power exponential equation. The smallest error that could be achieved between them was obtained and from this the mechanical properties of the material could then be calculated and analysed. Q345R steel, which is used for pressure vessels, was taken as an example and the mechanical properties were tested using the spherical indentation test, and the results were compared with the conventional tensile test. Comparative analysis of the mechanical properties of the steel between the results from the spherical indentation test and the conventional tensile test showed that the difference was small. The accuracy of the spherical indentation method when testing the mechanical properties of metallic materials is high. The results have shown that the spherical indentation test can be used as a replacement for the conventional tensile test and can be applied in the field of testing the mechanical properties of Q345R steel for pressure vessels.
Preparation and properties of GO-SiO2 anticorrosive coatings
Authors: Bai X L , Wu B , Jiang K , Liu C J , Zhang H , Zhang F , Huang X , Cai M J , Wang P F
Published: November 2019

Epoxy resin is often used as raw material of anticorrosion, but in the curing process of resin, a large number of micropores are prepared in the solvent evaporation method, which reduces the performance of anticorrosion. In order to reduce internal defects and improve corrosion resistance, GO was compounded with SiO2 modified by KH550 to prepare for GO-SiO2. By means of mechanical stirring and ultrasonic dispersion, GO-SiO2 was added to epoxy resin to prepare for the anticorrosive coating. SEM was used to observe the coating morphology, and the physical and electrochemical properties of the coatings with different mass fractions of GO-SiO2 are tested for corrosion resistance. The results show that 3 wt% GO-SiO2 coating shows the best performance, the coating hardness reaches H, the adhesion grade is II.
Phase composition and microstructure formation mechanism of in-situ Cu-Fe micro-composites
Authors: Liu K M , Jin Y , Sheng X C , Huang Z K , Zou J , Chen W , Zhang M C , Huang H M , Lu D P
Published: November 2019

The phase composition and microstructure formation mechanism of in-situ Cu-Fe micro-composites were investigated. The microstructures of longitudinal and transverse sections were analyzed by light microscopy and scanning electron microscopy. The phase analysis was executed by X-ray diffraction. The common microstructure characteristic of Cu-XFe (X = 11, 14 and 17) alloys was that the second phase α-Fe dendrites were uniformly distributed in the Cu matrix. The disorderly distributed Fe dendrites of Cu-14Fe alloy underwent initial inhomogeneous deformation and then were gradually changed into the directionally arranged Fe fibers of in-situ Cu-14Fe micro-composite in the longitudinal section, and were gradually transformed into the irregular V-shaped Fe fibers in the transverse section. The initial inhomogeneous deformation and the irregular V-shaped Fe fibers in the transverse section are closely related to the formation of <110> texture.
Research on speed regulation method of winding machine based on rectangular line mode
Authors: Zhang Y S , Ma H W , Wang H T
Published: November 2019

In the traditional semi-automatic winding machine winding process, the tension of the enameled copper wire changes greatly, and the cable is inaccurate, and cannot be separated from the manual machine. The emergence of automatic winding machine realizes the automation of winding production, reduces the labor intensity of winding, and greatly improves production efficiency. In order to improve the winding quality of the rectangular coil of the motor, a motor winding automatic winding machine is designed. The kinematics and dynamics analysis of the winding process of the winding machine were carried out. The kinematics of the enamelled copper wire and the working principle of the governing mechanism were studied. The kinematics mathematical model of the enamelled copper wire was simulated. The results show that the designed motor coil automatic winding machine has accurate cable routing and smooth winding process.
Microstructre and mechanical properties of Mg/Al joints by pulse MIG assisted induction pre-heating with composite interlayers
Authors: Zhang H C , Li L Y , Zhang G D , Hu Z H , Chen Y L
Published: November 2019

Butt Joints of AZ31 magnesium alloys and Al1060 aluminium plates were produced by conventional MIG welding process with composite interlayers composed of zinc, copper and aluminium foil and induction pre-heating method was used to promote the melting degree of the high melting interlayers, which achieved the connection of dissimilar materials effectively by comparison via SEM and tensile test. The results indicated that crack-free Al/Mg butt joints were obtained. The analysis of the microstructure of the joints showed that the phase composition at the interface between base metal and fusion zone related to the sequence of the different foils. The tensile strength of the joints could reach 21 MPa and the fracture located at the interfacial zone which was mainly composed of brittle Al-Mg compounds.
The effects of Ri/T ratio on residual stress of SAPH440 steel welding for auto parts
Authors: Chi L X , Liang S F , Yan B L , Gao X Z
Published: November 2019

In order to study the effect of Ri/T on welding residual stress in forging presses for Auto parts material, a welding experiment program was developed. The residual stress of thick pipe 10mm joint was measured by the blind hole drilling method. The simulation results within and near the weld joint, the transverse residual stresses are tensile on the inside surface which already close to yield strength with creasing the Ri/T ratio, and compressive on the outer surface; The prediction results from FEM are in a good agreement with the experimental measurement which are important to apply data for manufacturing plant.