Quality Of Surface Layer Research Articles

Influence of Contact Efforts on the Surface Quality of Difficult Profile under Finishing Hardening Machining

This work presents the research and development data in the field of finishing and hardening processes for parts with complicated shape surface. The comparable effectiveness of different surface finishing and hardening processes were studied, and intensification possibilities of processes of vibration finishing - hardening machining of narrow ducts by means of combined methods with metal anodic dissolution were shown. The results of experimental researches of influence of extrusion conditions of granular media on the surface layer quality are presented.

HONING PERFORMANCE ANALYSIS WITH PART HEIGHT PEN SPEED AT INTERNAL COMBUSTION ENGINES REPAIR

Both in the manufacture and repair of critical parts of mechanical engineering and engine building, great attention is paid to the formation of a trace on the surface, the surface layer quality and the geometric shape accuracy. However, methods of achieving high accuracy in the parts manufacture and their repair after operation differ significantly. The article assesses the possibility of implementing the honing method with a variable height speed of tool rotation (hon) patented by the author, and analyses the productivity of this method when repairing the internal combustion engines cylinder liner at a taper value of 0.20 mm.

Оценка несущей способности клеевых соединений с натягом

The experimental test results of glued-mechanical couplings of shaft — bush made with the use of anaerobic sealants are presented. Quantitative estimations of the surface layer quality of the mating parts were obtained that made possible to estimate values of surface waviness of the shaft and the bush. The methodology of the waviness determination of cylindrical couplings is described. The influence of fit on mechanical strength of the shaft — bush coupling depending on properties of a used anaerobic sealant was established.

Growth of high-quality epitaxy of GaAs on Si with engineered Ge buffer using MOCVD

This article presents novel process methods to grow GaAs on 200 mm Si substrates with low threading dislocation density (TDD) and no anti-phase domains (APDs). The GaAs layers were grown on the engineered Ge buffer with thickness of 0.9 and 1.7 μm with surface roughness as low as 0.58 nm. The growth temperature of GaAs was tailored from low, intermediate, and high temperature (LT, IT, and HT) at 460 °C, 600 °C, and 670 °C, respectively, to impede the defects to propagate to the HT layer. It has been demonstrated that the quality of GaAs layers is sensitive to the surface roughness and layer quality of Ge buffer. Therefore, Ge buffer was grown selectively with lateral overgrowth over the wafer to decrease the defect density to a low level as possible for GaAs growth. For all samples, Chemical mechanical polishing (CMP) was applied for Ge buffer to ensure the surface roughness prior to GaAs growth. This study presents novel methods to optimize/improve GaAs growth on engineered Ge buffer grown on 0° − and 6° − miscut Si substrates. The impact of layer quality, surface roughness, and design of Ge buffer growth (selective or non-selective growth) on GaAs growth has been studied. The outcome of this study provides a monolithic solution for photonics and electronics in large size Si substrates.

Modelling and prediction of surface roughness in wire arc additive manufacturing using machine learning

WAAM has been proven a promising alternative to fabricate medium and large scale metal parts with a high depositing rate and automation level. However, the production quality may deteriorate due to the poor deposited layer surface quality. In this paper, a laser sensor based surface roughness measuring method was developed for WAAM. To improve the surface integrity of deposited layers by WAAM, different machine learning models, including ANFIS, ELM and SVR, were developed to predict the surface roughness. Furthermore, the ANFIS model was optimized by GA and PSO algorithms. Full factorial experiments were conducted to obtain the training data, and the K-fold Cross-validation strategy was applied to train and validate machine learning models. The comparison results indicate that GA–ANFIS has superiority in predicting surface roughness. The RMSE, $$ R^{2} $$ , MAE and MAPE for GA–ANFIS were 0.0694, 0.93516, 0.0574, 14.15% respectively. This study could also provide inspiration and guidance for surface roughness modelling in multipass arc welding and cladding.

Surface Layer Formation at Dynamic Combined Exposure by Two-Component Electrode

This article is devoted to the study of workpieces surface layer state, resulting from dynamic exposure of a two-component electrode with imposition of electric field. The objects considered in the work are details with complex profile. Such parts are used in aviation, rocket and space technology and in oil and gas industry. They include impellers and flow part of turbopump bodies, augers, blade wheels, which have areas of variable curvature with limited tool access to treatment area. The authors show that mixture in combined process of two-component processing media from current-carrying granules and conductive liquid medium supplied at high speed to the treatment area, provides the required quality of surface layer due to the combined dynamic exposures on the material being treated. The parameters combination of electric field and kinetic energy of conductive granules allows you to control the magnitude and depth of material hardened layer in treatment area. Experimental studies have shown the increase in resource and durability of critical assemblies for aerospace equipment and oil and gas apparatus.

New technology for restoring Babbitt coatings

The reasons for reducing the durability of sliding bearings and the factors formed both at the stage of their manufacture and during operation are considered. Taking into account the types of destruction of sliding bearing coatings (exfoliation, disintegration of individual sections, field failure) the need for developing technological recommendations for their repair is demonstrated. The analysis of existing technological methods for restoring worn surfaces of parts is shown. The technique for applying the method of electrospark alloying to repair bearing liners is represented. The technologies of applying combined electrospark coatings to increase the adhesion strength of the substrate to the antifriction Babbit layer are described. There have been revealed the correlation dependences of the quality characteristics of the Babbit coatings restored by the method of electrospark alloying versus the technological parameters of the process. This makes it possible to significantly implement the methodology for controlling the surface layer quality while manufacturing and repairing the products with Babbit coatings. A technique has been developed for determining the mass transfer equation constants and for predicting the roughness. The mathematical models have been proposed to specify the quality parameters of the layers being formed in the course of the Babbit coating restoration based on the energy parameters of the electrospark alloying plant.

Influence of burning and weed control on the soil fertility and vegetation cover of Brazilian Amazon pastures

In pastures it is common to use fire to control weeds, justified by the increase in soil fertility that ashes can generate. However, the benefits of this process is short-lived, and also increase the soil exposure. The permanence of weeds can contribute to the vegetation cover in areas of deficient pastures. This study aimed to evaluate the effect of prescribed burning and mowing on vegetation cover of Urochloa brizantha (U. brizantha) pastures and soil surface fertility in pastures located in the Brazilian Amazon. The study was conducted in Itupiranga, Pará state, Brazilian Amazon. Five pastures of U. brizantha cv. Marandu and a forest area were evaluated. The soil was a Ferralsol. Vegetation cover was estimated using a quadrat. Four composite soil samples were taken in each area, collected from 0–0.05 m depth. The percentage of vegetal cover of U. brizantha, weeds and bare soil was measured and fertility in soil samples (pH, Al3+, Ca2+, Mg2+, K+, Na+, P, and H+Al) were determined. Three groups were identified in the evaluated pasture plots. Group I had the highest average percentage of bare soil (33.5%) and was associated with H+Al and P values. Group II had the highest average of U. brizantha cover (90%) and was associated with Ca2++Mg2+ and K+. Group III had the highest average of weed cover (53.4%) and was associated with Al3+. The higher percentage of U. brizantha in Group II was favored by the burning later. This group presented better levels of K+, Mg2+ and sum of bases. The management adopting the least use of fire on the pastures, with longer time for the regeneration of forage, combined with the mechanical control of weeds, can be the best alternative for maintaining the soil cover and bringing benefits for quality surface layer of the soil.

Arc Plasma Deposition of TiO2 Nanoparticles from Colloidal Solution

Surface modifications of metallic biomaterials can in great merit, improve the properties of the hard-tissue implants and in that way contribute to the success of the surgical implantation process. Coating deposition stands out as one of the many surface-modifying techniques that can be used to improve implant surface properties and, in turn, induce successful osseointegration. Deposition of the TiO2 layer on the surface of the metallic implants has a great potential to enhance not only their osseointegration ability but also their biocompatibility and corrosion resistance. In the present study, the possibility of successful deposition of the TiO2 layer on the surface of commercially pure titanium (CP-Ti), as the most commonly used metallic implant material, by spraying the colloidal nanoparticles aqueous solution in the electric discharge plasma at atmospheric pressure was investigated. To characterize the colloidal TiO2 nanoparticle solution, used for the coating deposition process, transmission electron microscopy (TEM) was utilized, while scanning electron microscopy (SEM) and optical profilometry were used to investigate the deposited surface layer morphology and quality. Estimation of the deposited film quality and texture was used to confirm that the arc plasma deposition technique can be successfully used as an advanced and easy-to-apply method for coating the metallic implant material surface with the bioactive TiO2 layer which favors the osseointegration process through the improvement of the implant surface properties. The TiO2 coating was successfully deposited using the arc plasma deposition technique and covered the entire surface of the CP-Ti substrate without any signs of coating cracking or detachment.

ON THE INFLUENCE OF OPERATING CHARACTERISTICS OF GRINDED WHEELS ON THE QUALITY INDICATORS OF GRINDED PARTS

The quality of the surfaces of roller bearing parts is formed in the process of interaction of the cutting tool with the surfaces to be treated. In addition to technological factors, a significant place in providing a quality surface layer is occupied by the correct choice of grinding wheels.
 The abrasive tool has different properties depending on its characteristics. When choosing an abrasive tool, it is necessary to take into account its characteristics and their suitability for a particular type of work. Stable operation of abrasive wheels depends on the correct choice of their size, characteristics and modes of operation.
 The selection of grinding wheels depends on the type and properties of machined materials, power of grinding machines, spindle speed, grinding mode, requirements for accuracy and surface cleanliness and other factors that apply to the workpieces.
 Depending on the accuracy requirements for machining parts made of different materials, the characteristics of abrasive wheels are selected, the main of which are hardness, grain size, bond, structure, shape, size and allowable speed.

Technological Assurance of Fiberglass Composites Surface Layer Quality during End Milling

Introduction. Today fiberglass is one of the most common composite materials. Therefore, its mechanical processing continues to be the subject of many studies. In many scientific publications, the influence of cutting modes and structural and geometric parameters of the tool on the roughness of the machined surface, cutting forces and wear of the cutting tool has been established. The purpose of this work is to study the effect of machining modes on delamination and roughness of fiberglass composites during end milling, as well as testing the hypothesis about the effect of torque on the delamination. The relevance of the study is due to the fact that delamination, along with roughness, has a significant impact on the quality of processing and subsequent assembly of the finished product. A criterion is proposed for assessing the magnitude of the delamination of composite materials during its machining. The results of experimental studies of the torque on the cutter, the relative coefficient of delamination and surface roughness from cutting conditions are presented. Methods: factorial experiment using an experimental assembly developed by the authors based on a piezoelectric torque sensor. The installation allows real-time recording of the change in torque during the milling process, depending on the modes of operation. Results and Discussion. A comparative analysis of the obtained dependences showed that the torque is directly related to delamination. To reduce the delamination, the depth of cut should be decreased, and in order to ensure the specified productivity, the feed and the rotational speed of the cutter should be increased. The presented results confirm the prospects of the developed approach aimed at machining new classes of composite materials.

ИССЛЕДОВАНИЕ ПРИМЕНЕНИЯ СОВМЕЩЁННЫХ МЕТОДОВ ОБРАБОТКИ МЕДНЫХ И АЛЮМИНИЕВЫХ СПЛАВОВ

The work purpose: the investigation of obtaining by a surface the required properties and possibility degree to control shaping processes. It is well-known that a shaping process is affected by many factors particularly at complex methods of processing. The analysis of machining condition impact upon surface layer quality of parts allows defining optimum parameters of cutting and increasing parts operation characteristics. 
 Investigation methods: theory, experimental researches, statistical processing of results, mathematical modeling, analysis. 
 Research results: there are defined criteria of surface quality at complex methods of shaping, roles of factors included in processing, mathematical models are formed, recommendations are formulated. 
 Novelty: it consists in the definition of regularities in pore covering at metal ceramic finish machining and definition of processing conditions impact upon pore covering, and also in the definition of efficient conditions of aluminum alloy finishing at the combined method of shaping. 
 Conclusions: as the investigations carried out show the combined methods of impact upon a surface at parts shaping allow reducing also cutter wear, minimizing collateral processing factors connected with heat generation, with increased friction forces and surface layer deformation of a billet at its processing. The combination of machining with electro-chemical processing allows not only having an influence considerable upon surface quality increase, but decreasing technological residual stresses and also contributing to the restoration of mechanical and physical properties of metal surfaces after electro-erosion processing at the expense of surface micro-layer elimination with the acquired thermal changes of structures.

Точность изготовления деталей из полимерных композиционных материалов

The main conditions of manufacturing support of the quality of polymer composite material components are set out. The life cycle, functional, design and technological tolerances, the surface layer quality and methods for providing preset accuracy are discussed. The classification of manufacturing types is given. The shrinkage effect is considered on an example of polymer composite components produced with different accuracy. The quality characteristics of the surface layers and the quality class values are presented for components based on the thermoplastic and thermosetting matrixes.

Rolled Stock Structure Preparation for Cold Forging of Pearlite Steel Grades

Special requirements are applied to the structural-mechanical characteristics of rod bolt products manufactured by cold die forging of pearlite steel class. A very common and productive method of obtaining finished metal products with high mechanical properties is their landing on cold heading (cold-heading) machines made of rolled metal, which must have a certain quality along the entire length: a sufficient ductility, homogeneous structure and parameters of technological properties, absence of any defects. Hardware plants receive the initial blank for the manufacture of various fasteners in the form of hot-rolled steel, which is not possible to use for the landing of high-strength hardware, due to the poor quality structure and surface layer. Therefore, the calibrated rolled stock is subjected to intermediate heat treatment before driving, which should guarantee the quality of the metal products at transitions of the cold heading. Further, the driven products of strength class 8.8 and up, made of alloy steel grades, must be subjected to hardening with subsequent tempering. However, such thermal operation often leads to decarburization of the surface, cracking and warping of finished products, thus increasing labor intensity, energy consumption and, consequently, the final production cost. The paper proposes an alternative method of the rolled stock structural preparation, which includes isothermal treatment of pearlite steel grades 35X and 38X, which excludes from the technological process the recrystallization annealing and quenching with the release of finished bolt products, and which minimizes any appeared scratches, warping and decarburization on the rolled stock and the rolled product. The structure of rolled stock induced in the drawing die, and the surface hardening by reduction, and thread rolling provide the parameters of mechanical properties of M8 bolts and pins, corresponding to the strength class 9.8.

Formation of surface layer quality under abrasive treatment of polymer-composite materials

Introduction. The study results of the abrasive processing of parts made of polymer-composite materials are presented. The features of processing polymer composites and the technology of preforming through waterjet cutting are described. The stages of preparation of a part made of polymer-composite material for the “glueing” operation are investigated. Materials and Methods. Dependences for determining the surface roughness under waterjet cutting of polymercomposite material are considered. Research is carried out to achieve the required surface roughness under adhesive bonding of workpieces. The dependence is given that describes the roughness that is required for a reliable adhesive bond. Results. The theoretical and experimental studies of the waterjet cutting process are resulted. Their implementation technique, the tool and equipment used are described. The results of theoretical and experimental studies are compared. Their high convergence is established. The results of experimental studies on the preparation of parts made of polymercomposite materials for glueing are shown. The abrasive tools and processing modes are selected. Discussions and Conclusions. The process design procedure of abrasive treatment of workpieces from polymercomposite materials is proposed.

Повышение производительности и качества обработки композиционных материалов на основе выбора и рационального применения абразивного инструмента

On the basis of the preliminary investigations on the orthogonal cutting dynamics there is offered and confirmed experimentally a hypothesis on possibility of composite efficient machining with an abrasive tool during drilling, milling and grinding. There are defined rational designs of abrasive tools and optimum machining modes ensuring the growth of productivity and quality of surface layers in polymeric composite parts.

APPLICATION OF THE CRITERION OF TECHNOLOGICAL DAMAGEABILITY IN MECHANICAL ENGINEERING

Development and implementation in mechanical engineering practice of integrated information systems for control of technological processes of manufacturing products is the main driver of economic growth of developed countries. The priority of modern engineering technology is to provide the specified operational characteristics of products in accordance with the accuracy parameters, set by designer and quality of surface layers in contrast to achieving the minimum technological cost with maximum performance for traditional approaches. Technological providing of the main operational characteristics of the product (bearing strength, wear resistance, fatigue strength, joint strength etc.) require a systematic approach, which consists in the investigation of real physical processes at submicroscopic, microscopic and macroscopic levels of research, and step- by-step tracking required parameters at all stages of the Product Life Cycle from the position of technological inheritability. It is proposed to use the method of LM-hardness to control the quality of the structure of the material from castings in the design of functionally-oriented processes. The magnitude of the technological damage of the product material serves as a criterion for optimization when choosing a variant of surface treatment of the casting. A method for providing experimental studies of castings of aluminium alloys has been developed. On the basis of the carried-out experimental researches the rational route of processing of surfaces of casting is chosen.

Increasing the operational reliability of car variators due to creating regular surface microrelief by laser ablation

The paper analyzes the car variator reliability issue. The variator performance is ensured by the surface layer quality, manufacturing accuracy, and the pulley and steel V-belt surface microrelief. The decisive factor in ensuring the variator reliability is the pulley finishing technique. Creating regular microreliefs on the finished pulley surface by laser ablation has been proposed, which act as micro-channels to improve the drainage of oil from the contact pattern. Creating oil channels on the pulley surface by laser ablation will ensure their arrangement and allow obtaining the desired pattern, direction, depth, and length.

Surface roughness variation in ultrasonic assisted burnishing of high-strength steels

Ultrasonic assisted burnishing process is a newly developed alternative of conventional burnishing process that enhances the surface properties of engineering materials. The process needs careful selection of design parameters to improve the quality of surface layer of workpieces made of high-strength steel that are difficult to deform. The analytical models to predict the surface roughness after the ultrasonic assisted burnishing process for surfaces are developed. Feed, ultrasonic influence power and static static force could be considered as main factors influencing to surface roughness at that feed has the greatest impact among other parameters. The models are verified by experimental studies with various ultrasonic burnishing parameters. Technological parameters of the ultrasonic burnishing are found, which decrease surface roughness from 1-2 μm to 0.05-0.55 μm. It is experimentally proved that feed increase results in surface roughness increase. To low the surface roughness of high-strength steel workpieces it is necessary to increase ultrasonic influence power with simultaneous static force lowering. The analytical models obtained in the present work may be employed in determining the best conditions for ultrasonic assisted burnishing in industrial field.

Transport properties of surface layers from full‐scale reinforced concrete member

AbstractThe durability performance of concrete structure is intimately related to the mass transport properties for the surface layers of concrete members. However, due to several effects, such as segregation, jamming effect and so on, the quality of the surface layer for reinforced member might be obviously different from their core material and material prepared and cured in the laboratory (labcrete). This study aims at understanding the mass transport properties of surface layers from reinforced concrete member, and clarifying the differences among them and those for accompanied labcrete. Specimens prepared from both a full‐scale reinforced beam and labcrete are subjected to experimental investigations on their gas permeability, capillary sorptivity, chloride diffusivity, and chloride migration coefficients. It is found that, for the same specimen, the gas permeability is approximately linear to capillary sorptivity. While the chloride diffusivity is smaller than the rapid migration coefficient. The durability potential of surface layers for the reinforced beam is inferior to that of the inner core material. While the latter is further obviously worse than that of labcrete. In engineering practice, special attention should be paid to ensure the quality of surface layer. When making quantification or prediction for the durability potential of concrete structure, it is more appropriate to use specimens from surface layers of field concrete members rather than those from labcrete.