Quality Of Surface Layer Research Articles

ANALYSIS OF SURFACE LAYERS OF HOT – FORGING DIES OF SKD61 STEEL FABRICATED BY DIE – SINKING ELECTRICAL DISCHARGE MACHINING USING COPPER AND TITANIUM ELECTRODES

Electrical discharge machining (EDM) is a popular unconventional method for manufacturing tools, molds, and dies. Currently, the surface layer of the hot die after EDM needed to be polished to remove the layer of » 50 mm. This is accepted according to practical experience and the lack of scientific basis because of limited research on the surface layer quality of the products after EDM and the study is focused on the evaluation of the product quality in the final processing. This study is aimed at the investigation of performance and structure of the surface layer in hot-forging die following die-sinking EDM. The machining conditions included the use of copper (Cu) and titanium (Ti) as electrode materials. A cross-sectional micrographic and hardness analysis was performed, as well as surface roughness measurements, in order to study the thermally affected zones of the hot-forging die surface layer of the SKD61 steel after EDM using oil as the dielectric fluid. The results showed that the performance of the die was reduced due to changes in the hardness and the chemical composition of the workpiece surface. The surface quality of hot-forging die after EDM with Ti or Cu electrode are similar. In this case, EDM using Ti electrode to improve the quality of hot die surface layer was unreasonable.

The Effect of Parameters Burnishing Rolling – Pressuring Process in Aspect to Technological Quality Surface Layer of 316L Stainless Steel

The Effect of Parameters Burnishing Rolling – Pressuring Process in Aspect to Technological Quality Surface Layer of 316L Stainless Steel

THE INFLUENCE OF SURFACE LAYER QUALITY ON THE PERFORMANCE CHARACTERISTICS OF MACHINE PARTS UNDER MACHINING

The paper highlights the classification of the quality parameters of the surface layer and their influence on the performance characteristics of machine parts, such as wear resistance, long-term and endurance strength, as well as the influence of quality parameters of the surface layer on the performance characteristics subject to the operating conditions (various temperatures and loads). The paper expounds the impact of machining conditions on the formation of surface layer quality indices and provides calculated dependences for the determination of surface layer quality parameters.

Analysis of Metal Flow Behavior and Residual Stress Formation of Complex Functional Profiles under High‐Speed Cold Roll‐Beating

To obtain a good surface layer performance of the complex functional profile during the high‐speed cold roll‐beating forming process, this paper analyzed the metal plastic flow and residual stress‐formed mechanism by using a theoretical model of the metal flow and residual stress generation. By using simulation software, the cold roll‐beating forming process of a spline shaft was simulated and analyzed. The metal flow and residual stress formation law in the motion were researched. In a practical experiment, the changes in the grains in the spline tooth profile section and the residual stress distribution on the tooth profile were studied. A microcorrespondence relationship was established between the metal plastic flow and the residual stress generation. The conclusions indicate that the rate at which the metal flow decreases changes gradually at different metal layers. The residual stress value is directly related to the plastic flow difference. As the roll‐beating speed increases, the uneven degree of plastic deformation at the workpiece surface increases, and the residual stress in the tooth profile is generally greater. At the same roll‐beating speed, the rate change trend of the metal flow decreases gradually from the surface to the inner layer and from the dedendum to the addendum. The residual stress distribution on the surface of the tooth profile decreases from the dedendum to the addendum. These findings provide a basis and guidance for the controlled use of residual stress, obtaining better surface layer quality in the high‐speed cold roll‐beating process of the complex functional profile.

The technology of combined processing of extruded materials

The paper considers the peculiarities of combined processing of parts, made from extruded metal blanks with anisotropic electrotechnical properties. It involves the application of an electric field and seeks to achieve the required profile accuracy in any processing direction with precision within the specified tolerance for finishing operations. The study describes the specific nature of the development of current leads and the ways of achieving the required accuracy when combining electro-erosion and electrochemical components of the process in real time, taking account of the position of the pressing force vector relative to the direction of current flow in the zone of combined processing. This gives the opportunity to ensure the process stability and accuracy of processing advanced materials with a wide range of current conductivity variation in components, used when extruding blanks for precision parts. The study employs the methodology of calculating and assigning technological modes of combined processing, formed on the basis of the energetic approach and using the principle of similarity in technological systems. It also involves the adapted process management which allowed for elimination of unstable impacts affecting the accuracy of shape formation and surface layer quality, and expands the area of using combined processing for manufacturing extruded parts with anisotropic properties of components. The article presents the feasibility study of the ways of extending the work results to various types of products, particularly, to processing of welded and soldered joints of metallic materials and coated details where the replacement of traditional processing methods with combined ones significantly increases the opportunities for obtaining high-precision parts with required performance characteristics.

Analysis of possibilities of high-speed prototyping technology in hot section manufacturing

The article is devoted to the exercising of a trial technological process for the manufacture of gas turbine engine (GTE) hot sections by the example of a solid-cast nozzle block. To do this, the authors made up a plan of the experiment associated with the search for optimal conditions and parameters of a technological process of the sector master mold layer-by-layer synthesis from a photopolymeric material. The paper tracks the interconnection between the parameters of a 3D printing system Objet Eden 350 and the materials in the growing process by the PolyJet technology and mechanical properties of a master mold in the context of their influence on the surface layer quality and geometric accuracy of the final GTE parts’ casting. Based upon the analysis of the obtained research results and taking into account technical requirements, the authors managed to grow a nozzle block sector master mold, get wax models and conduct an experimental casting of a solid cast nozzle block wheel.

Evaluation of conventional standards of nickel electroplating process for surface finish layer of AISI 316L stainless steel using copper rod bars as cathode

Nickel electroplating process at UD Barito Electroplating is a modern methodology installed in an open complex environment and at controlled temperature with trust consideration of specimen composition. The evaluation of process at UD Barito has been undertaken by considering Stainless steel AISI 316L as specimen through a conventional nickel electroplating process. This paper presents the proper scientifically tool to be used at UD Barito in order to meet the time required and the surface layer quality of the electroplated product. The use of ultrasonic to replace air compressor assembly does not cause any harm to the surface finish smoothness and the quality of plated specimen given that the process is conventional. Concerning the process of 10 min compared up to 15 min of the process at UD Barito; showed the facility of ultrasonic assisted the electroplating process. This process is also a useful method in maintenance activities for surface cleaning and for product surface-layer quality enhancement through the coating process. From the data analyzed, the specimen has a hydrogen embrittlement rate range between 20 to 65% of Rockwell scale HRC52.

Mathematical modeling of vibroburnishing of the hole of cylinder

The authors obtained dependencies of the surface layer properties after machinig cylinder holes by vibroburnishing. The properties of the surface layer are changed from a variety of vibroburnishing factors. Surface layer quality graphics of the machining parameters are obtained by mathematical modeling using formulas derived empirically. During the processing of experimental data, the authors of the articles identified optimal processing regimes in which parameters of the quality of the surface layer of the billet can be specified. Thus, vibroburnishing is better to make machining on the mode: m = 16,5 mm, i = 1,7 mm, α = 7,5 °, Ay = 160 J, ƒ = 20 Hz. It was found that the greater vibroburnishing tightness is, the greater the value of size of the cold-hardening layer is. Rougher surface will always have bigger tightness of burnishing, i.e. the purer surface is, the lower the value of tightness of a vibroburnishing must be. However, in the process of a vibrational burnishing of holes there is a so-called critical point, roughness of a surface decreases and the surface layer of metal is strengthened before reaching this point, and after reaching it there is a phenomenon of a re-cold-hardening and quality of a surface decreases.

Качество поверхностного слоя лопаток компрессоров из титана при многокоординатном глубинном шлифовании

The investigation results of technological conditions impact at multiaxes deep grinding upon quality of titanium alloy blade surface layer in the compressors of gas turbine engines (GTE) are presented. The grinding mode impact upon a surface and a value of residual stresses in a surface layer of blades is defined and also conditions for defect occurrence as burns on blade surfaces under machining are detected.

Obróbka elektrochemiczna – stan badań i kierunki rozwoju

Electrochemical machining process (ECM) can be applied for efficient shaping advanced materials conducting electrical current, which are difficult or impossible for machining using conventional methods. In electrochemical machining, the workpiece is an anode and material is removed as a result of electrochemical reactions “atom by atom” without mechanical forces. This mechanism of material removal make it possible to obtain high quality of machined surface layer with uniform properties. The very important advantage of ECM process is also the fact that there is not a tool wear (working electrode – cathode), because the equivalent reaction to anodic dissolution is hydrogen generation on cathode surface and hydrogen can be easily removed from, the inter-electrode gap by electrolyte flow. Because of this advantages, the ECM process is widely applied in space, aircraft, car and electromechanical industry and research stimulating ECM development are carried out.

Новые технологии повышения качества поверхностного слоя при резании волокнистых полимерных композиционных материалов

Новые технологии повышения качества поверхностного слоя при резании волокнистых полимерных композиционных материалов

Method for Determining Fatigue Limit Taking Into Account the Effect of a Surface Layer

A method is proposed for determining the fatigue limit of metallic material components based on measuring hardness, production residual stresses, surface roughness, and some other parameters. A dependence is given for fatigue limit on surface layer quality parameters. Application of the method is demonstrated on the example of steels 30KhGSNA, U8, titanium alloy VT3-1, and aluminum alloy D16 after different treatment.

Influence of Chemical Composition of Tough-to-Machine Materials on Grinding Technologies

The main purpose of processing of tough-to-machine materials is improving of cutting process of steels with different physicochemical properties and alloying by means of various chemical elements in combination with heat treatment. Producing of high quality surface layers depends on properties of material used to make details, that is why reasons of tough machining were identified: influence of chemical composition and resulting structure. The studies of grinding of tough-to-machine materials were undertaken by means of grinding wheels made from synthetic diamonds as they are most resistant and highly-productive. Based on the studies recommendations for using of characteristics of grinding wheels and tough-to machine steel grades.

Расчётное определение степени влияния покрытий режущего инструмента на параметры качества поверхностного слоя обрабатываемых деталей

The impact of cutter wear-resistant coatings upon cutting process parameters and characteristics of surface layer quality in the parts worked: residual stresses, a degree and a depth of work hardening of a surface layer, surface roughness is investigated.

The influence of burnishing parameters on the hardness and roughness on the surface layer stainless steel

Purpose: The aim of the study was description to the influence of technological parameters of burnishing process on the degree of relative strain hardening and surface roughness reduction ratio. Design/methodology/approach: Burnishing process carried out for stainless steels X2CrNiMo17-12-2. After the experimental research, it was determined that there was an increase in hardness and a decrease in roughness. The hardness was measured with the use of Vickers hardness tester. Observation of the microstructure of stainless steel samples was carried out using scanning electron microscopy and optical microscopy. The parameters of surface roughness measurements were performed to the principles contained in ISO standards. Findings: In the production and regeneration of metal products used in machine elements is important to technological quality surface layer. In surface engineering one of the ecological and economic treatments used for endurance and technological properties is burnishing. This is a surface forming a local plastic deformation based on the overall impression given by smooth and hard tool. Practical implications: The burnishing due the technological and economic aspect in the production and regeneration of machine parts in exchange for the abrasive processing can be used. In production engineering or technology of repair cylindrical outer surfaces (e.g. plugs propulsion shaft centrifugal pumps seawater) are finishing. You can therefore propose burnishing in exchange for abrasive machining. Originality/value: Important question to determine in the article of the research was to received appropriate technological quality. After the tests, it was found that the technological parameters are influenced by the hardness and the roughness of the outer cylindrical surfaces and the material ratio curve a convex shaped, which, taking into account the load capacity of the surface will be directly affected by its resistance to wear and corrosion of the surface layer.

Influence of the microstructure of Al–Si alloy on the surface-layer quality in microarc oxidation

The properties of the hardened surface layers formed by microarc oxidation on Al–Si alloy billet are investigated. The microhardness, thickness, and porosity of the surfaces formed depend on the alloy structure.

Analysis of Surface Layer Defects on Carburized Steel Component after Alkaline Blackening

Alkaline blackening is one of the most popular surface treatment technology of components with the requirement for higher surface corrosion resistance, increased hardness, and the decorative appearance.This contribution deals with the appearance of surface defects on carburized steel components after the process of alkaline blackening, which appeared to be red shiny stains on an otherwise black matte surface of the component. The occurrence of defects on surface was observed several days after the alkaline blackening process. By means of metallographic methods, direct connection between surface defects and the microstructure of the material was found.Contribution further deals with the influence of microstructure and technological parameters on the quality of the final surface layer of the components.

Relationship between Oxidation of Metal Surface Layer and Air Quality in Wuhan

In order to find out the relationship between the oxidation of surface layer and air quality, the correlation analysis method and elemental analysis is used in this paper. Based on the analysis of the database of RAPIDC Corrosion Project, dose-response functions for the tested metals were derived through non-linear regression method. The established dose-response functions for carbon steel and zinc are applicable to use in Wuhan and the results show that the proposed method can thus improve overall system performance substantially.

Relationship between Oxidation of Metal Surface Layer and Air Quality in Wuhan

Relationship between Oxidation of Metal Surface Layer and Air Quality in Wuhan

ОСОБЕННОСТИ ПОВЕДЕНИЯ СМАЗОЧНО-ОХЛАЖДАЮЩЕЙ ЖИДКОСТИ (СОЖ) В ЗОНЕ КОНТАКТА ИНСТРУМЕНТА С ЗАГОТОВКОЙ

The relevance of the issue selected for the study is proved by the fact that, when producing optical parts, the treatment using loose abrasive is replaced with the processes based on the application of fixed abrasive. However, the increase in efficiency causes the issues of the surface layer quality assurance. It is caused by the fact that the intensification of the stock removal process is inextricably connected with the heat output increase in the contact area of a tool with a workpiece. The paper presents the methodology of the study and the obtained observation results of fracturing behavior of lubricating-cooling fluid in the contact area of a tool and a workpiece. The temperatures in the area of treatment of optical materials determine considerably the quality of treated surface. During these processes, the lubricating-cooling fluid plays one of the key roles. It is impossible to develop the exact thermophysical model of the process of treatment without the true recording of lubricating-cooling fluid and its behavior. For the direct vision of the lubricating-cooling fluid behavior in the contact area of a tool with the treated surface, the author developed the method based on the strobing freeze application. A pulsed lamp is installed in such a way that the total internal reflection from the prism working surface would take place. In case, some body contacts with this surface, the total internal reflection gets broken and the dark spot with the actual contact geometrics can be observed. Using the device, it is possible to observe the treatment area. Carried out study allows concluding that the lubricating-cooling fluid is constantly present in the treatment area. All areas of the direct contact of a tool and a workpiece are surrounded with it. When using water-based lubricating-cooling fluid, there are no areas free of it at the applied velocity of cutting out of certain contact areas.