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Reinforcement ratio and bar splice methods have an indubitable effect on the behavior of RC beam-column joints. The present experimental study is focused on evaluating the influence of parameters including reinforcement ratio of beams, method and number of splices on the performance of RC beam-column joints under dynamic loads. To aim this goal, four RC beam-column joints with different numbers of forging (GPW) or mechanical splices (threaded couplers) in the longitudinal bars of beams were tested under cyclic and axial loads applied to beams and columns, respectively. Force-drift hysteresis curves are provided and seismic parameters including displacement ductility, absorbed energy and stiffness are investigated and discussed. More importantly, the results of this study are compared to the results of other specimens available in the literature with similar splice methods but different reinforcement ratio examined under the same loads in order to figure out the effect of reinforcement ratio on the performance of joints with bar splices. Results indicated that the joints incorporating forging method exhibited more appropriate response in comparison to those with threaded couplers by showing more ductility, absorbed energy and stiffness. Moreover, it was observed that reinforcement ratio does not significantly affect stiffness of the specimens with different numbers and types of splices whereas ductility and absorbed energy changes remarkably by changing types and numbers of spliced bars when reinforcement ratio alters.

The outer dimensions and 3D model of ring forgings in industrial production are the important parameters to ensure the quality of the products. In order to realize the measurement of the outer dimensions and 3D model of the ring forgings, a measuring method for the ring forgings combining with a CCD camera and a 2D laser scanner is proposed in this paper. Firstly, the image information of the ring forgings is obtained by the CCD camera. The radiuses of different sections for ring forgings are acquired by pixel calibration and edge detection. Secondly, the point cloud data of different sections are obtained by laser scanner with the movement of the transmission mechanism. Then, the position discrimination method of straight line fitting is used to reduce the error data. And the radius matching method is used in the further processing of the point cloud data based on image detection, and the point cloud data with high accuracy is further extracted. Finally, the 3D point cloud data and 3D model of the ring forgings are obtained by rotating the 2D point cloud data. The outer dimensions of forgings are derived from the 3D model. The experiments were carried out with two different ring forgings. According to the experimental results, the feasibility of the method proposed in this paper is verified.

In this study, residual stresses of cold-forged ball studs were investigated by the contour method with using widely available wire-Electro-Discharging Machine (wire-EDM) and Coordinate Measuring Machine (CMM). After the wire-EDM cutting, one of the steps of the contour method, it was revealed that the surface contour data was affected from the cutting step. Therefore, to increase the accuracy of the measured residual stresses, one of the ball studs were heat-treated to normalize residual stresses due to cold forging. The contour data of the heat-treated sample was subtracted from the as-forged surface contour to eliminate any cutting-induced artefacts. The final residual stress profiles suggested that the subtracting procedure minimized the cutting errors. In addition, a new classification approach for the cutting-induced errors for the contour method was introduced. According to final stress maps obtained by the contour method, it was revealed that high compressive residual stresses were obtained at the socket regions of the ball studs, as expected. Balancing tensile residual stresses were observed at the inner regions.

Compared with the general multi-degree-of-freedom motor, the permanent magnet spherical motor has the advantages of simple structure, convenient control and small size. This paper analyzes the cogging torque of a surface-mounted spherical permanent magnet motor (SSPMM) with an 8-pole, 12-slot three-layer stator. The SSPMM has two kinds direction of cogging torque: rotation direction and deflection direction. In order to weaken the multi-directional cogging torque, a new auxiliary slot shape was proposed. Through theoretical analysis and finite element simulation, the FEA is compared with the analytical results to verify the accuracy of the method. It is verified that the research method can effectively reduce the cogging torque amplitude in two directions.

Artificial intelligence and Internet of Things (IoT) technology, which are the core of the 4th industrial revolution, can resolve many problems that optimization of production times in the manufacturing process and reduction of materials required etc. In order to utilize the 4th industrial revolution technology, real-time monitoring technology of metal parts is essential, so technology for embedding sensors and IC chips into parts is essential. Using metal 3d printing technology, it is possible to embed IC chips into metal parts, which was impossible because of the existing high-temperature metal manufacturing process of casting or forging. Here we introduce a novel new method for sensor embedding into SUS316L by hemisphere design to avoid direct laser exposure onto sensors during selective laser melting process. Thermal and microstructural analysis was carried out to characterize the property of inner hemisphere for safe thermal couple embedding into SUS316L.

The effect of 3 forging routes (Route A - 1~12 passes by plane forging (PF) and reverse-plane forging (R-PF), Route B – 1~6 passes by PF and R-PF, 7~12 passes by diagonal forging (DF) and reversediagonal forging (R-DF), Route C – 1~12 passes by DF and R-DF) on maximum load to produce the workpiece, deformation heterogeneity and hydrostatic pressure distribution in AA1100 was theoretically investigated using finite element analysis (FEA). The maximum load per pass required to complete 1 cycle of the SPD process was different depending on the forging routes. Route A was relatively higher than Route B and C. From the results of effective strain, the deformation heterogeneity was predicted at the center, edge, and corner regions of the AA1100 workpiece produced by Route A and B. However, the distribution of effective strain in Route C was relatively more homogeneous than Route A and B. The average hydrostatic pressure, which is closely related to the suppression of crack formation in the workpiece under multi-axial forging, was predicted to be relatively bigger in Route C than Route A and B.

In the forging industry, rolling is used to produce ring forgings, which are widely used in power and nuclear engineering. According to the technical conditions and established practice, large ring forgings are made using the operations of precipitation, piercing and rolling out with a striker on the mandrel.

Вступ. На ранніх стадіях проєктування суден, їх спуску зі стапеля, постанов- ці в док та в навчальному процесі можуть бути використані наближені методи оцінки загальної та місцевої міцності суден. Запропоновано нову версію удоско- наленого та універсалізованого методу п’яти моментів (М5М). Метою дослі- дження є розробка нової версії М5М для стержневої моделі згинання суднових перекриттів із вирішенням таких завдань: врахування в балочній моделі судно- вих перекриттів нерегулярності розміщення балок головного напряму (БГН) та перехресних балок (ПБ) при їх непризматичності, довільності граничних умов, розподіленні навантаження на розглядувані балки; врахування деформації зсуву в стінках балок перекриття; врахування полосового навантаження від спускових доріжок та докового опорного пристрою (ДОП) під час докування суден. Резуль- тати. Розроблено комп’ютерно орієнтований метод розрахунку згинання судно- вих перекриттів з урахуванням їх особливостей у проєктуванні суден, спуску зі стапелю та докуванні. Висновки. Розроблено алгоритм і розрахункову методику з розгляду задач розрахунку згинання перекриттів у процесі проєктування суден, їх спуску з поздовжнього похилого стапелю та постановки в сухий або плавучий доки. Реалізована удосконалена балочна модель оцінки згинання суднових пере- криттів на основі М5М, який поширений та універсалізований для практичних розрахунків з урахуванням таких факторів: нерегулярність розстановки балок перекриття, довільності їх граничних умов; розподіл навантаження між балка- ми обох напрямів і видів навантаження на перекриття; врахування деформації зсуву в стінках балок; врахування особливостей деформування днищових пере- криттів суден під час їх спуску з похилого поздовжнього стапелю і докування за рахунок розгляду полосового навантаження балок.

6XXX series aluminum alloys are generally excellent alternatives to steels for many forged parts in aerospace and automotive industries. In this study, the forging performance of the 6082 aluminum alloy is investigated in order to replace the existing material for forged steel parts. The effect of artificial aging of the alloy on the microstructure and mechanical properties is studied. Optimum aging conditions are determined. Results reveal that AA6082 could be a good replacement for applications where shock and vibrational loads exist. The rod end automotive part currently manufactured from AISI1045 can be replaced by AA6082 without any design changes. The major drawback is that the cold forging of the aged alloy is poor due to its brittle nature and crack initiations. Therefore, warm or hot forging is recommended to overcome the poor forgeability.

Background: Cold forging operation is done on small as well as large scale in manufacturing industries. These industries are facing problems such as higher rejection rate of the final product, low productivity, the high number of accidents during production, etc. Objective: The purpose of this research work is to develop a Voice-Assisted Forging System (VAFS) with a lower rejection rate, higher productivity, and lower number of accidents during production. Methods: Based on recently published journals and patents, traditional and automatic forging operations, Industry 4.0, and voice assisted systems are reviewed and VAFS is designed and developed. Then, the trial is taken on VAFS to investigate its performance. Finally, limitations and future research of the VAFS are proposed. Results: It is found that after implementation of the VAFS the average rejection count is reduced by 90.3 percentage, the operational productivity is increased by 71.2 percentage, and process accuracy is increased from 92.75 percentage to 99.30 percentage. Also, the number of accidents is reduced to zero. In comparison with the manual forging operation, the VAFS occupies less space, and it is easy to operate. Conclusion: This system will help the workers as well as the owner of industries to create a better man and machine relationship and to have a human-friendly working environment. VAFS reduces exhaustion and hassle of employees, components rejection, and energy consumptions in the production line.

Building on growing interest in the development of the ninth art in Spain, this article returns to a foundational work by creator Pere Joan that encapsulates Barcelona’s role in forging the post-di...

This study reports on the forging simulation of P91 steel at a temperature range of 900–1200°C and a strain rate range of 1–15 s−1 using Deform 3D finite element software. The study investigated th...

The manufacture of tools such as machetes in Banten is still widely practiced, machetes are produced from a conventional forging process using a hammer by a blacksmith. Working as a blacksmith in the Banten area, especially in the village of the new village of lightning, was passed down from generation to generation as a traditional blacksmith, but over time the machetes produced by traditional blacksmiths began to be replaced by modern ones machete. The traditional golok of Kampung Baru Village, Petir, consists of two types, the regular machete and the sulangkar golok. The material commonly used by blacksmiths to make machetes is a vehicle spring sheet that is no longer used, while for making machetes, a blacksmith usually combines other materials during forging. The purpose of this study was to determine the differences in the mechanical and micro properties of the two types of golok, Banten cultural heritage. The research was carried out from the start of the search for the material, the manufacturing and forging processes and carried out testing. The results of the hardness test show that the value of the spring material is 423.1 HBW, SS 400 steel material 134.18 HBW, combination material or Sulangkar 735.15 HBW then the data results from the tensile test on steel material SS 400, Spring, Combination or Sulangkar are 442.52 MPa, 1334,60 MPa, 522.81 MPa. The results of the data from the impact test on Spring material, SS 400 steel, Combination or Sulangkar, namely 162 J, 34 J, 88 J. The results of automatic microscope testing and Scanning Electron Microscope (SEM) show the surface of the spring, SS 400 steel and combination materials.

Concerning the demand for upscaling in severe plastic deformation (SPD) processes, in this research, a novel method is presented, during which a billet with a rectangular cross-section is enforced under a cross-sectional shear strain, and its cross-section is changed to the parallelogram. Then the parallelogram is again enforced under another cross-sectional shear strain, and its shape is changed back to the original rectangular shape. Due to the form of the deformation and the manner in which cross-section changes, the method is entitled “Simple Shear Forging” (SSF). A new apparatus was designed and manufactured to impose plastic strain on the billet in a plane strain condition, while a hydrostatic pressure is applied, and without any change in the cross-sectional area, which ensures the repeatability of the process. In order to study the process parameters, most notably friction and pressure, simulation of the process was carried out using the commercial finite element code ABAQUS/Explicit, and the resultant strain distributions were investigated. The presented method is applied to Al 1050 billets, and the Vickers microhardness test was carried out for different numbers of applied passes. The results indicate that the SSF method is capable of introducing high strain values and grain refinement. Unlike most of the previous methods, it is not necessary to remove and reinsert the billet after each pass, which consequently enhances the productivity of the process significantly.

Combination of transient computational fluid dynamics simulations of a gas-fired heat treatment furnace and experimental validation were carried out to investigate the applicability of equilibrium ...

The multi-directional forging process of aluminium alloy 7075 (AA 7075) is studied using Deform 3D Version 11.0 simulation software. This process results in grain refinement in the bulk material. The 7075 aluminium alloy is used widely in the aerospace and automobile industries. Thermomechanical processing affects the mechanical properties of this alloy. This study focuses on optimising process parameters that affect the multi-directional forging using simulation. In the Taguchi design of experiment, four-factors and five levels are selected. The process input parameters considered are temperature, the strain per pass, the plunger speed, and the friction coefficient (μ). From Taguchi’s orthogonal array, forging simulations are undertaken and analysed. The significance of the process output parameters: material damage, stress and strain are analysed by analysis of variance. The results show that the friction coefficient and strain per pass highly affect the stress/strain distribution. Grey relational analysis is adopted to determine the optimum process parameters. The results show that the optimal combination of parameters is: temperature (200 °C), plunger speed (5 mm/s), friction coefficient (0.6), and strain per pass (0.6). Confirmation of simulation is carried out using the optimum input parameters. From the simulation results, the grey relational grade's optimal parameters have the highest maximum effective strain of 5.57, maximum effective stress of 665 MPa, and maximum damage of 0.416 compared to other simulated results.

Additive manufacturing enables the manufacturing of parts with complex geometries that are not easy to be manufactured by conventional methods such as machining or forging. Despite their numerous advantages, additive manufacturing methods have some drawbacks, such as poor surface quality as a primary concern. Parts with high surface roughness tend to show poor fatigue resistance; thus, they cannot be reliable under dynamic load conditions. Therefore, additively manufactured parts should be subjected to additional surface finish operations to improve surface quality and eliminate the negative effects of surface roughness. In this review, one of the most popular methods among modern surface finish processes, known as laser polishing, has been discussed. Process parameters, changes in processed part morphology, and applications along with the advantages and limitations of the method have also been explained to have a good understanding of the importance of this promising method.

Manufacturing processes such as casting, rolling, forging, extrusion, material removal processes, etc. are some of the common techniques used today in manufacturing industries. However, these proce...

Closed die forging of spur gears is investigated using the slab method and the upper bound technique. The tooth regions are approximated by prismatic rectangular sections. The velocity field comprising three unit deformation regions is used. A constant frictional stress between workpiece and forging die is assumed. The average punch pressure normalized by the flow stress of the gear material is determined theoretically and compared with experimental results. The experimental work is carried out on a commercial pure aluminum (Al 1100) at room temperature. The forging process is carried out using one die geometry without using any additional blocker (preform) dies. The theoretical predictions of forging pressures and deformation configurations agree fairly well with the experimental results.

Cold forging tools fail mainly due to loss of dimensions (as a result of abrasive wear and plastic deformation) and fatigue failure. Since tooling costs represent a considerable share of the total cost in forging processes, improving fatigue life is a crucial aspect in the design of forging tools. The present study aimed to improve the fatigue life of a specific cold forging tool currently employed in the mass production of an automotive part. The stresses in the die were evaluated by means of finite element simulations, which were able to predict both the crack nucleation spot and its propagation direction, as observed in the tools employed in the production line. There is compelling evidence in the literature that fatigue life of a die is influenced by the amount of interference fit (preloading) to which it is subjected. Therefore, a slight alteration in the preloading profile was proposed, and the finite element analysis was repeated. Numerical results predicted a change from 597 MPa to 170 MPa in the highest principal stress. The design modification was then implemented in the production line and the expected mean life increased from 17,563 to 71,323 parts produced per tool. Overall, the procedure herein described may serve as a valuable tool for the design of cold working tools less prone to fatigue failure.

The article describes experiments on the reconstruction of the technology of the one-step process of obtaining iron-carbon alloys in furnaces based on archaeological sources. It contains the description of furnace design, metallurgical process technology and raw materials preparation. The process of refining the iron bloom by forging is described. Scientifically grounded assumptions are made about possible technological methods of obtaining steels in the pre-industrial period on the territory of modern Belarus.

Based on the hot compression experiment of GH4169 superalloy, the constitutive equation and the microstructure evolution model of GH4169 superalloy were established, and they were introduced into the Deform® simulation software to realize the simulation of the microstructure evolution of GH4169 superalloy in closed multidirectional forging, single-sided open multidirectional forging, and bilateral open multidirectional forging. The neural network prediction model of the microstructure of GH4169 superalloy in multidirectional forging was established using MATLAB, and the neural network prediction of microstructure evolution in three kinds of multidirectional forging was determined. Experimental results show that the prediction error of the two methods for the recrystallized grain size doesn't exceed 10%, and the error under high pass is small. For the recrystallization volume fraction, the prediction errors of the two methods are less than 3.5%, and the prediction error of the neural network for higher pass deformation is lower than the finite element simulation. The established neural network model has high prediction accuracy and can be used to predict the microstructure evolution of GH4169 during hot deformation.

The feasibility of using deep learning techniques in industrial cold forging for fault detection was investigated. In this work, vibration data were collected from an industrial setting to detect m...

Objective: The aim of this paper is to understand a production system of a forging and presses structure of a centenary factory in terms of a cultural change on the management approach. Methodology: The study was focused on many aspects such as the pieces production lead time, a time study of the setups, the Overall Equipment Effectiveness determination for the Computer Numeric Control machinery and an analysis of the production cells operational flow. Findings: For the aspects that were analysed during the study, the problems are identified, and the root causes determined. At the end of the assessment stage Lean tools and concepts for fixing the problems were proposed, like new rules for production planning, setups procedures, 5S toll usage and a Lean implementation plan that is adapted to the company. Value Added: The high industrial competitivity has dictated the development for this sector that – allied with the inconstant and unstable economic environment – makes the companies very vulnerable and highly dependent of the global market. This is a concern of special relevance for the Small and Medium Size companies that are increasingly adopting Lean solutions to continuously improve their operational value chain and the management approach, for a more systemic way of thinking. Recommendations: For some of the solutions an impact study with their implementation was made. An analysis of the success factors proposed in the literature that were verified during the assessment stage of the case study was performed as well.

A combination of unsteady 3D CFD simulations and experimental temperature measurements was employed to determine the effect of loading patterns on the temperature distribution within steel forgings inside a gas-fired heat treatment furnace. This was aimed to obtain a more homogenous temperature distribution. Besides, a hybrid methodology using 3D numerical simulations and a high-resolution dilatometer allowed improving residence time of forgings inside the heat treatment furnace. The influence of the loading patterns and skids on temperature distribution and residence time of forgings was examined using thermal analysis four different loading patterns. Comprehensive unsteady thermal analysis of the products heating allowed quantifying the impact of skids usage and their dimensions on the extent of the uniformity of temperature distribution. The results were interpreted in terms of the inter-relationship between the skids usage, their geometry, absorbed radiation, and convective heat fluxes. The analysis showed that temperature non-uniformities of up to 331 K could be produced for non-optimum loading patterns. Using the developed CFD approach, it was possible to reduce the temperature non-uniformity of different sizes of blocks up to 32% via changing the loading pattern inside the furnace. Further, the slab’s residence time was improved by almost 15.5% when employing the proposed hybrid approach. This approach could directly be applied to the optimization of different heat treatment cycles of forged blocks in different grades of steels.

Recognition of malposition and location of high-temperature forgings play a critical role in the realisation of robotised die forging, which is an ongoing trend in intelligent manufacturing. This study is aimed at the robotised die forging of the scraper beam of armoured face conveyor, which is the only transporting equipment used in the coal mine workface. Firstly, a novel process to recognise the malposition and location of high-temperature forgings using two monocular cameras, one placed horizontally and another vertically, is proposed. Secondly, a novel image preprocessing algorithm combining the algorithms of grey linear transformation, exponential transformation, and median filtering is proposed. After processing the high-temperature forging image using the proposed image preprocessing algorithm, the grey difference between the target region and background region of the processed image is highly increased. This is conducive to the subsequent image segmentation and contour extraction processes conducted in the forging region. Thirdly, after the comparison and analysis of the three commonly used image segmentation methods, including edge detection, threshold segmentation, and region growing methods, it is discovered that the region growing method is suitable for image segmentation of high-temperature forgings. Fourthly, a two-way modified and blob analysis based forging location algorithm is proposed to reduce the location error caused by the axial and radial asymmetric flash during the forging process. Finally, the proposed algorithms are validated by experiments and the location recognition error of the proposed location algorithm is only 0.86059 mm. This study provide technical support for the realisation of robotised die forging.

This paper explains the methodology of developing an open die-forging model using Deform-3D software to simulate the hot forging process on Ti-6Al-4V billet used in aerospace applications. Three-di...

This paper reports the influence of thickness and material attenuation on volumetric inspection using conventional and advanced ultrasonic array-based techniques through suitable examples. The sensitivity achieved in conventional phased array ultrasonic testing technique with focusing at specific depth using delay laws and advanced array-based techniques for simultaneous focusing at all depths such as Full Matrix Capture-Total Focusing Method and plane wave imaging-TFM are compared in the present study. Finally, experimental results are discussed for advanced ultrasonic array-based techniques for detection and characterization of a 4 mm through wall dimension vertical planar defect (simulating a lack of side wall fusion in a thick narrow gap weld) in a nickel base alloy forging having fine and coarse grains. The sensitivities and signal-to-noise ratio achieved in the different techniques are discussed in detail.

Due to problems in manufacturing process and forging technology, some of the workpieces production in the workshop have defects, which affects the ornamental value and utility of the workpieces. At present, the detection of workpiece defects is still mainly relying on manual detection, which consumes human resources and has a high detection error rate. To solve the above problems, deep learning is used to improve the detection of workpiece defects and reduce the cost of workpiece production. This article uses Faster R-CNN1 as the basic architecture and integrates Resnet502 as the backbone network. In addition, Deformable Convolutional Networks3 is introduced to extract defect features of different forms, and the multi-scale transformation problem is solved through Feature Pyramid Networks4. Comparing with YOLOv35, Faster R-CNN, Mask R-CNN6 and other models, the results show that the mAP of the object detection model based on Faster R-CNN is 89.21%, the detection effect is the best, and it can meet the actual production needs.

The uses of Artificial Intelligence (AI) and Machine Learning (ML) are topics of presentations at most conferences today across diverse professional disciplines. Why? The following quote says it all

Properties of graphene, such as electrical conduction and rigidity can be tuned by introducing local strain or defects into its lattice. We used optical forging, a direct laser writing method, under an inert gas atmosphere, to produce complex 3D patterns of single layer graphene. We observed bulging of graphene out of the plane due to defect induced lattice expansion. By applying low peak fluences, we obtained a 3D-shaped graphene surface without either ablating it or deforming the underlying Si/SiO2 substrate. We used micromachining theory to estimate the single-pulse modification threshold fluence of graphene, which was 8.3 mJ cm−2, being an order of magnitude lower than the threshold for ablation. The control of exposure parameters allowed the preparation of blisters with various topographies. The optically forged structures were studied with atomic force microscopy and Raman spectroscopy. Optically forged blisters act as building blocks in the formation of more complex structures. We found a simple geometric rule that helps to predict the shape of complex patterns which are created by the overlapping multiple exposures. Optical forging enables writing of extended patterns with diffraction unlimited features, which makes this method promising in the production of nanodevices with locally induced surface modifications. peerReviewed

The aim of this study was to create a new approach for awareness analysis by means of Taguchi Signal-to-Noise Ratio to assess Forging technology performance to effectively improve technology awareness. Also, see the impact of new technology awareness in forging Industry, Micro small and Medium Enterprises (MSMEs). In the present study the Taguchi Signal-to-Noise Ratio approach was applied to process the Ordered Categorical Data, and acquired into account at the same time the effect of mean and variance as well as awareness and no awareness information to suitably pinpoint the enhancement direction of technology attributes. With northern Indian, 86 MSMEs as the research theme, this study deliberated the approach and benefits of using Taguchi Signal-to-Noise Ratio to technology awareness analysis. The less aware forging technology attribute was identified and implemented in the industry to see the impact in the Forging Industry. Results explicitly describes that Forging die lubricants is the less aware technology attribute of new technology. Results indicate the net savings of rupees 522,572 or 7465 US dollars annually after implementing new technology attribute in a case Industry. The paper establishes the practical use of new forging technology awareness presenting how it can bring real developments in saving cost in the forging Industry.

Metallurgists and engineers are focusing on developing of forged turbine blade with different materials during the last three decades. This forging method has been developed to the theme where INCONEL alloy is formed. Blades are playing a vital role on the turbine. These blades can be manmade to exact geometry shape and reliable surface with metallurgical characteristics. This study focuses on a gas turbine blade in 3D design software and finite element analysis with ANSYS software. From the reference, the thermal boundary conditions on the rotor blade are referred. The distribution of temperature across the blade is got. The utmost stress which the blade can endure is found and the distribution of stress across the blade is got consequently. The outcomes got are associated with N-155, Mild Steel and the most appropriate material is conversed.

The O–O bond-forming step in the oxidation of water to dioxygen is the key to how nature converts solar energy into renewable fuel, yet remains not fully understood. A recent report in Nature Chemistry from Casadevall et al. features structural characterization of a catalytically relevant elusive peroxo intermediate.

The trend towards lightweight design leads to an increasing demand for sophisticated part geometries with high functional integration. In order to use the advantages of cold forging regarding the time- and resource-efficient production of high-quality parts, high local stresses causing fatigue failure in geometrically complex tools have to be controlled. The objective of this manuscript is to analyse the use of stress pins for a local influence on the stress state within forging, especially in non-circular symmetrical cold forging dies. For this purpose, a closed-die forging process for elliptical parts is designed and analysed regarding the die stresses. Distinct areas with local compressive and tensile stresses occur in the process. To counteract the tensile stresses critical for fatigue failure, the effect of stress pins pressed into the die creating a local prestress is analysed. Around the pins, compressive radial and tensile tangential stresses occur. While large pin diameters, interferences and close positioning to the tensile area lead to an increasing prestressing effect, too high values of these parameters cause a detrimental superposition of tensile process and pin stresses. If used correctly, there is high potential to improve the stress state and tool life especially for locally stressed complex tools.

The article is devoted to description of changes in traditional metallurgy of Daghestan in connection with the development of Russian industry in the first half of the ХIХ century, the development of new technologies of metal processing in the province (locksmith business, etc.). There is an expansion of directions in the assortment of metal products, which appeared in Daghestan in the second half of the XIX – the beginning of the XX centuries. Many processes are illustrated by examples from the craft history of the famous Harbuk blacksmith center.

The authors of the article justify the expediency of applying resource saving in developing innovative technologies for hot rolling of boning knife blades from steel slabs. Such knives are widely used in meat processing industry. Metal consumption of the process was significantly reduced after changing the existing factory technology of making boning knives. The operation of cutting or grinding was replaced by hot rolling. The specific feature of the technology lies in minimizing the metal loss into shavings during the final processing of the steel slab by means of cutting. Reducing metal loss in making such steel parts and raising metal utilization rate are achieved by maximum possible approximation of forging configuration to the end product contour and preservation of the allowances regulated by the operational chart. The authors suggest optimal combinations of basic parameters of introduction of resource saving technology into production. To adduce an example the authors justify the possibility of shaping and simultaneous hardening of the knife blade during hot rolling between deforming rollers. Energy intensity of the technology suggested is lowered by means of reducing the time for further mechanic processing of the forging by cutting. Practical approbation of the introduced resource saving technology in repair production made it possible to raise the metal utilization rate to 95% and to reduce by 1.2 the production cost of a boning knife as the end product. When manufacturing the parts metal resources are saved due to the fact that irreversible loss of metal in the innovative technology of the boning knives’ production differs a lot from that in the traditional one. Technical and economic calculations adduced in the article show the effectiveness of the research and prove the profit of implementation of the new technology

The process of hot die forging of AK4-1 aluminum alloy billets for the piston of an internal combustion engine (ICE) for an unmanned aerial vehicle (UAV) was simulated using the Deform-3D software package. The object of research was an ICE piston mounted on one of the UAV types of Russian production. Simulation was performed using the following parameters: tooling and billet temperature was 450 °C, ambient temperature was 20 °C, punch speed was 5 mm/s, and Siebel friction index was 0.4. Rigid plastic medium was chosen as a material model. The number of elements (6000) was selected so that at least 3 elements fit in the narrowest section of the part. Thus, as illustrated by the piston die forging, computer simulation in the Deform-3D software makes it possible to develop hot die forging processes for making aluminum alloy billets for UAV ICE pistons. At the same time, computer simulation can be used to evaluate the power parameters of the hot die forging process, study the nature of billet forming in die forging, make necessary adjustments to the virtual process, and develop the design of a die forging tool in order to select the most effective process solutions when designing a real process. The described computer simulation technique can be extended to other aluminum alloy die forgings.

The saw stability in operation defines the ability of the saw blade to resist the forces acting on it in the plane of greatest rigidity. The saw can work reliably only in case of maintaining stable balance, which is achieved through the creation of normalized residual stresses in certain zones of the saw blade by different methods. The stresses balance the forces of external influences. Compressive stresses are created in the central part of the blade to make the circular saw operational. These stresses compensate the forces of centrifugal acceleration, temperature heating of individual zones of the saw blade, external longitudinal and transverse bending forces arising in material processing. In practice, the creation of normalized stresses in the saw disk is traditionally carried out only by local mechanical contact action (forging, rolling) of the saw blade tool on the steel saw blade. It is proposed to form the stressed state of the disk by thermophysical action instead of the traditional mechanical processing of the saw blade. The thermophysical action involves the creation of normalized residual stresses in the saw blade by the concentrated thermal exposure to local differently directed narrow-band zones of straight or deflected shape, mainly radial or along concentric traces, controlling the process in real time. A new approach to the formation of residual stress fields in the saw blade by thermoplastic action enables to radically change the settingup procedure of the circular saw, ensuring its stability in operation.For citation: Melekhov V.I., Solovev I.I., Tyurikova T.V., Ponomareva N.V. Improving the Stability of Wood-Cutting Saws by Thermoplastic Action on the Distribution of Residual Stresses in the Blade. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 6, pp. 172–181. DOI: 10.37482/0536-1036-2020-6-172-181

Beam-column joints affect the performance of structures remarkably, therefore, finding an appropriate method for their construction has always been one of the major concerns of researchers. In the present study, the influence of incorporating mechanical and forging (gas pressure welding) splices in longitudinal reinforcement bars of beams on the cyclic performance of RC beam-column joints is evaluated experimentally. Totally five RC joints with non-spliced, mechanically (threaded couplers) spliced and forging spliced bars were examined under axial and cyclic loads applied to columns and beams, respectively. Crack propagation of specimens are analyzed and load-drift hysteresis curves are provided as test outputs. Moreover, the influence of the splice method and number of spliced bars on joints’ behavior is assessed in terms of seismic parameters including displacement ductility, stiffness and cumulative absorbed energy. Results showed that forging splices can be considered as an efficient and reliable method for bar splicing and mechanical splices might affect joints’ behavior significantly.

This article proposes a novel analytical model which combines subdomain method and magnet equivalent circuit (MEC) method to predict the cogging torque of surface-mounted permanent magnet (SPM) motors with rotor eccentricity and magnet defects in any slot-pole combination cases. Firstly, the general solution of open-circuit magnetic field distribution in a slotless SPM motor with magnet defects is derived. Then, the motor is divided into several subdomains along the air-gap circumferential direction to consider the non-uniform air-gap caused by rotor eccentricity, where the air-gap lengths of each subdomain are considered to be uniform. Finally, the methods of conformal mapping and MEC combined with equivalent current is used to consider the effect of slotting and saturation, which is beneficial to improve the calculation precision. The magnetic field distributions and cogging torque calculated by the proposed model are consistent with the results of finite element analysis (FEA). Compared with the FEA, the proposed model can perform fast calculations of air-gap flux density and cogging torque under rotor eccentricity and magnet defects for SPM motors, which can be utilized for optimizing the motor towards fault tolerance.

In the current research environment, the potential contribution (and guidance) of aspiring undergraduates is often neglected. Here, Ye Tao from the Rowland Institute discusses the opportunities and challenges to foster this next generation of scientists and proposes three guiding principles of successful undergraduate mentorship.