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The liner is affixed to the inner side of the ball mill cylinder to protect the cylinder. Through isothermal compression experiments, Arrhenius constitutive models, peak strain models, critical strain models, dynamic recrystallization dynamic models, and grain size models suitable for the forging process of Mn–Cr–Ni–Mo steel used in ball mill liners were established. By utilizing Deform software, a 3D thermo‐force‐structure coupling model for the hot forging process of ball mill liners was constructed, and the volume fraction of dynamic recrystallization and average grain size during forging was predicted. The response surface model was employed to investigate how process parameters interacted with each other and affected microstructure uniformity in ball mill liners. After optimization, the optimal parameters were determined: initial forging temperature at 1200 °C, forging speed at 30 mm s−1, and friction coefficient at 0.3. Subsequently, a hot forging experiment on ball mill liners was conducted using these optimized parameters; samples were analyzed through backscattered electron diffraction device experiments and microscopic tissue observations. Results demonstrated that microstructural changes observed during actual forging processes aligned with numerical simulation results—thus verifying both the accuracy of the Mn–Cr–Ni–Mo steel material model and numerical simulation method. [ABSTRACT FROM AUTHOR]

Structural automotive components are extensively made of aluminum alloy forgings, due to the elevate strength and low weight required. These products are frequently subjected to recrystallization. Recrystallization, often limited to surface or forging portions, is expected to reduce its tensile strength and corrosion resistance, but the literature is scarce on this subject. For a more comprehensive understanding, the present research studied the corrosion behavior of samples collected from EN AW 6082‐T6 forged components, designed to expose both recrystallized and not recrystallized surfaces to the corrosive environment. Several standardized corrosion tests (i.e., PV 1113, ISO 11846, and VW 96380) were applied to assess the most representative with respect to real field exposure. Tensile tests were performed in four different conditions, recrystallized and not recrystallized specimens in an as‐forged state or after corrosion. The recrystallization led to a reduction in tensile properties, but this gap was compensated by a higher corrosion resistance than the not recrystallized samples. Consequently, the mechanical properties became comparable after the corrosion test. [ABSTRACT FROM AUTHOR]

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aluminium finds wide application in mechanical engineering due to its low density and corrosion resistance. In this research, aluminium was subjected to two different metal forming technologies—cold forging (upsetting) and equal channel angular pressing (ECAP)—to obtain improvement in its exploitation properties. Parallel to changing mechanical properties by using these two processes, there was a change in the microstructure of the material. The resulting microstructures were examined using an optical microscope. A different treated aluminium was subjected to erosion wear in various time intervals. Wear testing was conducted for two different impingement angles causing abrasive wear and impact wear. The erosion mechanisms were examined by scanning electron microscopy. These results showed that there is no statistically significant difference in erosion wear for different states at the same impingement angle. However, the difference is noticeable at different wear angles. The significance of the difference in wear of the samples treated with the forging and ECAP techniques was validated by statistical analysis with tests of different sensitivities. The results of the t-test showed that ECAPed samples present a statistically significant difference in the loss of mass due to variations in erosion angle during the 30, 45, and 60 min wearing. A substantial difference in the change in sample mass is also visible for the forged state worn for 60 min. [ABSTRACT FROM AUTHOR]

The traditional method of manufacturing propellant tanks for rockets and spaceships involves significant amounts of forging, and machining, making it expensive and environmentally unfriendly. A novel approach for manufacturing propellant tanks that reduces the need for machining and friction stir welding processes has been presented in this paper. This approach involves manufacturing a tank half starting from a single metal plate, using innovative and advanced metal forming processes such as hot stretch forming, magnetic pulse forming, hub forming, and integrated stiffened cylinder (ISC) flow forming followed by orbital welding of two tank halves. A life cycle assessment (LCA) study was conducted in accordance with ISO 14044:2006 standard using the ReCiPe 2016 Midpoint (H) method to compare the environmental impacts of the traditional and newly developed approaches for manufacturing propellant tanks. The results of the LCA study showed that the new approach based on advanced forming technologies reduced carbon footprint by 40%, cumulative energy demand by 35%, water footprint by 17%, and materials waste by 4% compared to traditional manufacturing. The lower environmental impact of the new approach was attributed to a decrease in friction stir welding requirements due to the implementation of advanced forming techniques that enable integrated tank production. This lowered the overall energy consumption in the novel approach by a factor of 1.5 and in turn resulted in lower environmental impact compared to traditional forging and machining-based method. Furthermore, a futuristic scenario that involves in-house tank production using the novel approach with minimal transportation of inventories was also simulated. Based on the LCA results, it was seen that the newly developed approach for manufacturing propellant tanks was more environmentally friendly than the traditional approach and its environmental footprint could be further reduced by implementing the futuristic scenario with minimal transportation. This novel approach is also expected to reduce the lead time and production cost of manufacturing a propellant tank. Hence, future efforts in cost assessment and further optimization of raw material and energy usage are recommended. [ABSTRACT FROM AUTHOR]

Bangladesh is increasing agricultural mechanization to reduce labor-intensive drudgery and to address labor shortages in farming. Agricultural equipment, such as power tillers and threshers, are used to achieve this goal and require regular replacement of the spare parts that experience significant wear in use. Spare parts are currently imported at twice the cost of domestic ones. This paper supports the development of domestic manufacturing by analyzing the manufacturing processes for two fast-moving spare agricultural parts, tiller blades and threshing teeth, and providing a method to develop more efficient processes. The manufacturing processes, which focused on the design of forging and bending dies, reflect the constraints of the manufacturing equipment and stock materials available in Bangladesh. The die designs and manufacturing processes were verified by FEA simulations and by experimental testing. The experiments and simulations suggest that the spare parts should be made at elevated temperatures and high rates of forming. Recommended die designs and processing conditions and forces required to achieve the final part and that can be implemented in manufacturing facilities in Bangladesh are presented. [ABSTRACT FROM AUTHOR]

The Industrial Metrology Business Unit of Nikon Corporation, on behalf of ScottishPower Renewables and Maritime Archaeology (MA), Southampton, UK, has employed X-ray CT (computed tomography) to visualise the internal structure of an anchor found in the North Sea. The non-destructive method of internal inspection and measurement has helped to determine approximately when it was made. The results indicate that the artefact, initially thought to be potentially Roman, is probably more recent, likely dating to between the late 16th and early 17th centuries CE. This paper presents the discovery, recovery, analysis and interpretation of a significant find from a UK offshore wind farm and underscores the valuable role that non-destructive X-ray CT played in the investigation.

High-strength metastable β-titanium alloys like Ti-5553 (Ti–5Al–5Mo–5V–3Cr) are frequently used in highly loaded aerospace components. Such aerospace parts tend to be expensive to traditionally manufacture due to current industry process limitations such as inflexibility for complex geometries, costs related to tooling for large forgings, extended lead times, poor machinability and high material waste. These challenges are leading to increased interest in exploring alternative manufacturing routes. This work investigates the use of additive manufacturing to deposit cost-effective and machinable Ti-64 (Ti–6Al–4V) alloy onto a forged Ti-5553 alloy substrate. The microstructure evolution, microhardness and tensile properties have been investigated for both the as-deposited as well as for stress relief heat-treated conditions. The results confirmed the formation of coarse columnar β grains with a fine basketweave α structure. The heat affected zones (HAZs) developed in the Ti-5553 substrate material from the cyclic thermal fluxes introduced from the melt-pool were characterized by a gradient microstructure of dissolving constituent phases with nearing proximity to the fusion zone. Tensile testing in the as-deposited condition was characterised with a UTS of 884 MPa and a ductility of 15%. Tensile samples extracted across the substrate-deposit interface all failed in the WAAM Ti-64 material and demonstrated comparatively greater strength but poorer ductility. A band of tensile residual stresses was imparted along the substrate, but was adequately stress relieved after heat-treatment at 600 °C. The heat-treatment led to the formation of more homogeneous α-phase laths throughout the HAZ of the Ti-5553 material and provided overall improvements to the strength and ductility.

Forging is a traditional and important manufacturing technology to produce various high strength products and is widely used in engineering fields such as automotive, aerospace and heavy industry. To produce highly accurate product, underfill that the material is not filled into the cavity should strongly avoided. For material saving and near-net product, flash should be minimized. To make the tool life long, it is preferable to produce product with low forging load. It is also preferable to uniformly deform the billet as much as possible for high strength product. Crack is a crucial defect and should strongly be avoided. Therefore, many requirements are taken into account in order to produce the forged product. To meet the requirements, design optimization in forging coupled with computer aided engineering (CAE) is an effective approach. This paper systematically reviews the related papers from the design optimization point of view. For the billet or die shape optimization, the papers are classified into four approaches. The process parameters optimization such as the billet temperature, the die temperature, the stroke length and the friction coefficient is conducted, and the related papers are also classified into four categories. The design variables and the objective function(s) used in the papers are clarified with the design optimization technique. The multi-stage forging including the hammer forging for producing complex product shape is also briefly reviewed. Finally, major performance indexes and the future outlook are summarized for the further development of design optimization in forging. [ABSTRACT FROM AUTHOR]

Copyright of Steel Pipe is the property of Steel Pipe Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Closed-die forging preforms are usually made by open die forging operations, which are subject to significant variabilities. A sensitivity study covering a wide range of influencing parameters has highlighted the predominant influence of the initial billet geometry. The forging die strokes were also highly influential, while their fidelity is sufficient to use them as control parameters in order to compensate the geometrical dispersions of the billet. Consequently, their optimization was performed by taking a nominal preform geometry as the target. Polynomial surrogate models have been constructed to enable real-time optimization. A specific preform was used as a demonstrator in this study, while the approach was generic. The surrogate models were built using data from finite element simulations, which were first validated with an experimental campaign. On the one hand, this approach introduced agility by allowing changes in the billet geometry, and on the other hand, it allowed individual customization of the specific route to each billet. [ABSTRACT FROM AUTHOR]

The Industrial Metrology Business Unit of Nikon Corporation, on behalf of ScottishPower Renewables and Maritime Archaeology (MA), Southampton, UK, has employed X-ray CT (computed tomography) to visualise the internal structure of an anchor found in the North Sea. The non-destructive method of internal inspection and measurement has helped to determine approximately when it was made. The results indicate that the artefact, initially thought to be potentially Roman, is probably more recent, likely dating to between the late 16th and early 17th centuries CE. This paper presents the discovery, recovery, analysis and interpretation of a significant find from a UK offshore wind farm and underscores the valuable role that non-destructive X-ray CT played in the investigation. [ABSTRACT FROM AUTHOR]

Tube hydroforging with non-circular shaping has been conducted to show the deformation mechanics of an AHSS tube. In this paper, the tube was hydroforged in a multistage FEA simulation to show the effects of axial forging distance on noncircular cross-sections during hydroforging. The tube will be allowed to expand with a ramped internal pressure, then be shaped to a certain expansion ratio by the axial compression in the forging step and finally be shaped into either a square or an equilateral triangle shaped cross-section. It was observed that triangular shaped models have a greater resistance to thickness loss than the square shaped models. The forging die distance for both square and triangular shaping models each influence the maximum amount of shaping die distance for the process. The simulations show that as the forging die distance increases, the lateral radius increases for both the square and triangular shaped models. For the square shaped models, there is an uncorrelated relationship between the vertical and horizontal longitudinal radii but is correlated in the equilateral triangle configurations. The thickness distributions for the triangular shaped configurations show greater stability in the deformed wall portion than the square shaped configurations. All the model setups failed due to wrinkling, except the triangular shaped model with 20 mm of axial displacement, which failed due to bursting. [ABSTRACT FROM AUTHOR]

The quests and advocacies for co-operations, alliances, integration and unity amongst African countries are quite historical, and are ever resonating in discourses on international relations. It is such advocacies that birthed the idea for the formation of the Organization of African Unity (OAU), Economic Community of West African States (ECOWAS), Southern African Development Community (SADC), etc. Unfortunately, not even the rationale for the metamorphosis from OAU to the African Union (AU) has been able to entrench the much desired unity of purpose amongst African states. This paper posits that the conversations on strategies for a closer and sustainable integration in Africa should not only be centred on socio-economic and political paradigms, but should deeply reflect cultural cum educational matrixes. The paper hypothesizes that cultural transmission, which is a fundamental goal of any educational system, has to be emphatically explored in the drive for integration and unity in Africa. It therefore conceptually highlighted the link between culture and education in regional integration, with reminiscences of such linkages in Africa. The paper however observes that, beyond the affirmations and declarations arising from Treaties and Charters by some regional fora in Africa, the varied uses of education for the purposes of cultural transmission, promotion of African history and languages, in addition to the merits of intellectual exchanges, are to be further surveyed as the plausible templates that would encourage integration in Africa. Consequently, the paper suggests that socio-political institutions, governments, sub-regional blocs and other agents of diplomacy and development in Africa should carefully reconsider the multi-dimensional values of education in the realization of the dreams of African nationalists for a well-integrated and united Africa. [ABSTRACT FROM AUTHOR]

Nowadays, cold forging is one of the most commonly utilised methods in industrial manufacturing, and most metal-forming lubricants are not ecologically friendly; in some cases, these chemicals may produce large chemical emissions and pose a risk to the community. Bio-oil lubricants have garnered increasing attention as potential alternatives for mineral oil-based lubricants, since they are critical in resolving existing obstacles. This article intends as a case study and demonstrating the usage of different derivatives of palm oil as a bio-lubricant in the closed forging test (CFT). As an outcome of the friction, wear behaviour and deformation, the closed forging test is important in the knowledge of materials and engineering studies. In this test, aluminium (A1100) was utilised to compare the formation of the workpiece using palm oil based and commercial metal-forming oil as a benchmark lubricant. During the forging process, these components' material flow patterns are analysed at intermediate phases of the die stroke level. Using the experimental data, the finite element approach will be used to predict the workpiece friction, effective stress and metal flow. By developing a Coulomb–Tresca friction model, a cold forging test also was used to do studies on the interaction between the Coulomb friction coefficient (CFC) and Tresca shear friction (TSF). From the results, certain types of palm oil-based lubricants perform better than mineral oil-based lubricants in terms of friction coefficient, with palm stearin having the lowest friction coefficient (m = 0.33/µ = 0.139), followed by palm kernel oil and palm mid olein (m = 0.39/µ = 0.159). The palm oil-based lubricant, on the other hand, has generated poor performance in terms of surface texture and surface roughness (Ra) with a high rate of wear compared to the no sample lubricant and commercial metal-forming oil (m = 0.42/µ = 0.1675). [ABSTRACT FROM AUTHOR]

As a field of forensic science, graphoscopy studies the legalities of writing and develops methods for examining and identifying the person who forged a document or signature. The identification is made on the basis of an expertise carried out by an expert in the field, ordered by the competent bodies.

A technique for simplified simulation of the forging of large ingots using modern machine-learning methods for constructing models that describe stages of thermomechanical processing is described. [ABSTRACT FROM AUTHOR]

This paper presents a method for applying forging to high-density wood. A cylindrical container was formed using a closed die, and the appropriate conditions for temperature and punch length were evaluated. Ulin, which is a high-density wood, and Japanese cedar, which is a low-density wood and widely used in Japan, were used as test materials. The pressing directions were longitudinal and radial based on wood fiber orientation, and the shape and density of the resulting containers were evaluated. In the case of ulin, cracks decreased by increasing the temperature, while temperature had little effect on Japanese cedar. Containers without cracks were successfully formed by using a punch of appropriate length. The density of the containers was uniform in the punch length l = 20 and 40 mm in the L-directional pressing and l = 20 mm in the R-directional pressing when using ulin, with an average density of 1.34 g/cm3. This result indicates the forging ability of ulin is high compared to that of commonly used low-density woods. In summary, this paper investigated the appropriate parameters for forging with ulin. As a result, products of more uniform density than products made by cutting were obtained. [ABSTRACT FROM AUTHOR]

The evolution of eutectic Si morphology and microsegregation during homogenization heat treatment at 753K was examined for Al--Si--Cu--Mg--Ni alloy casting billets. Subsequently, casting billets homogenized at 753K for 0 s, 7.2 ks, and 28.8 ks were forged, and microstructures and mechanical properties at 473 and 573K were investigated for the forgings with different sizes of eutectic Si. Spheroidization of eutectic Si and elimination of microsegregation were achieved during the heating process of homogenization heat treatment. The spheroidized eutectic Si then coarsened with the homogenization heat treatment time. The interparticle spacing of the eutectic Si and constituent particles after the forging process increased with the coarsening of Si particles during homogenization heat treatment. In the tensile test at 473 K, the 0.2% proof stress, ultimate tensile strength (UTS), and elongation of the forgings were almost the same regardless of the homogenization heat treatment time, i.e., the size of eutectic Si. On the other hand, forgings made of a billet with a shorter homogenization heat treatment time showed more pronounced work-hardening behavior and higher 0.2% proof stress and UTS at 573 K. The increase in strength was explained by the enhancement of workhardening associated with the decrease in interparticle spacing, which depends on the Si particle size after homogenization heat treatment. [ABSTRACT FROM AUTHOR]

The evolution of eutectic Si morphology and microsegregation during homogenization heat treatment at 753K was examined for Al-Si-Cu-Mg-Ni alloy casting billets. Subsequently, casting billets homogenized at 753K for 0 s, 7.2 ks, and 28.8 ks were forged, and microstructures and mechanical properties at 473 and 573K were investigated for the forgings with different sizes of eutectic Si. Spheroidization of eutectic Si and elimination of microsegregation were achieved during the heating process of homogenization heat treatment. The spheroidized eutectic Si then coarsened with the homogenization heat treatment time. The interparticle spacing of the eutectic Si and constituent particles after the forging process increased with the coarsening of Si particles during homogenization heat treatment. In the tensile test at 473 K, the 0.2% proof stress, ultimate tensile strength (UTS), and elongation of the forgings were almost the same regardless of the homogenization heat treatment time, i.e., the size of eutectic Si. On the other hand, forgings made of a billet with a shorter homogenization heat treatment time showed more pronounced work-hardening behavior and higher 0.2% proof stress and UTS at 573 K. The increase in strength was explained by the enhancement of workhardening associated with the decrease in interparticle spacing, which depends on the Si particle size after homogenization heat treatment. [ABSTRACT FROM AUTHOR]

The article concerns the use of the results of numerical simulations, primarily for the detection of defects in forged products identified at various stages, along with the analysis of the geometry of forgings and the way in which the material flows in tools. The work presents the results of measurements and analyses using numerical modelling based on computational packages dedicated to forging processes such as: QForm, Forge, etc., which are equipped with special functions that significantly facilitate analyses by both technicians and designers. These functions include: contact of the deformed material with the tool, flow line distribution, "trap" or "fold" functions for detecting forging defects, as well as other technological parameters and physical sizes, which are crucial in the case of a comprehensive analysis of the industrial die forging process. The novelty of the work is the presentation of the possibility of simultaneously combining many different non-destructive techniques and methods, e.g. results of FE simulations with 3D reverse scanning, minimizing interference in the industrial process. The research carried out allows for the thorough and rapid analysis of the correctness of the deformation of the forging material for selected forging processes, along with the presentation of methods for their prevention and solving various technological and engineering problems, which is particularly important in terms of reliability and production efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Litua: Studies & Research / Litua: Studii și Cercetări is the property of Muzeul Judetean Gorj Alexandru Stefulescu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents methods for improving the quality of forgings and workpieces obtained by forging by intensifying shear or alternating strain in the bulk of the deformed metal. To increase the metal processing due to shear or alternating strain during forging, forging strikers are most often used, the feature of which is the geometric configuration that creates additional metal flows. Quite a lot of works from research teams from all over the world have been devoted to the problem of intensive metal processing during forging. In these publications, a number of new unique designs of strikers have been proposed and various route technologies have been considered, which can significantly increase the level of shear or alternating strain compared with the use of traditional forging tool designs.

Aluminium finds wide application in mechanical engineering due to its low density and corrosion resistance. In this research, aluminium was subjected to two different metal forming technologies—cold forging (upsetting) and equal channel angular pressing (ECAP)—to obtain improvement in its exploitation properties. Parallel to changing mechanical properties by using these two processes, there was a change in the microstructure of the material. The resulting microstructures were examined using an optical microscope. A different treated aluminium was subjected to erosion wear in various time intervals. Wear testing was conducted for two different impingement angles causing abrasive wear and impact wear. The erosion mechanisms were examined by scanning electron microscopy. These results showed that there is no statistically significant difference in erosion wear for different states at the same impingement angle. However, the difference is noticeable at different wear angles. The significance of the difference in wear of the samples treated with the forging and ECAP techniques was validated by statistical analysis with tests of different sensitivities. The results of the t-test showed that ECAPed samples present a statistically significant difference in the loss of mass due to variations in erosion angle during the 30, 45, and 60 min wearing. A substantial difference in the change in sample mass is also visible for the forged state worn for 60 min.

The main objective of the present work is to produce AlxCoCrFeNiMo0.5 alloy through a wrought process. AlxCoCrFeNiMo0.5 high-entropy alloys with two different Al contents (x = 0.2 and 0.5) were prepared by vacuum arc melting followed by thermo-mechanical processing. Microstructural evolution was investigated after hot forging and subsequent homogenisation using XRD, SEM, and TEM. The final microstructure corresponding to Al0.2 and Al0.5 are BCT (sigma) in the FCC matrix and BCT (sigma) and ordered BCC together in the FCC matrix respectively. Room-temperature mechanical properties were investigated using uniaxial compression and hardness measurements. There is an apparent increase in strength and a decrease in ductility for the Al0.5 alloy. However, a higher ductility was observed in Al0.2 alloy with a compromised reduction in strength. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine if forged TiAl alloys are worth using for small parts such as jet engine turbine blades. As part of this goal, this study investigated ways to improve the impact resistance of forged TiAl alloys and compared them to cast TiAl alloys. The effects of additive elements and microstructure on the impact resistance of forged ternary TiAl alloys of 43.5 at. % Al were evaluated using the Charpy impact test on specimens heated to 500 °C prior to testing. The impact resistance of the forged alloys improved with the addition of Cr, V, and Mn and deteriorated with the addition of Nb. The impact resistance of the microstructure containing a β-phase, a common microstructure in forged TiAl alloys, was significantly lower. The fully lamellar structure obtained at the expense of forgeability showed much higher impact resistance than this. However, even the best impact resistance of the forged alloys was significantly inferior to that of cast ternary alloys of 46.5 at. % Al prepared with the same additive content. Combined with the high cost and low high-temperature strength of the forged TiAl alloys, it is concluded that it is pointless to use forged TiAl alloys for small parts that can be made via casting. [ABSTRACT FROM AUTHOR]

Work-related illnesses and the resulting employee absences can have a major impact on productivity and competitiveness, especially in small and medium-sized enterprises. Particularly in the forging industry, the manual handling of forged parts leads to high physical stress and thus to frequent illnesses of the musculoskeletal system, especially of the hand-arm system. One possibility to counteract this circumstance is the use of ergonomic forging tongs. In the study presented here, the influence of ergonomic forging tongs on the physical stress of forging employees was investigated by simulation and experiment and compared to conventional forging tongs. Within the simulation and the experimental investigation, forging parts and forging tongs were varied. In the simulation, an ergonomics assessment of the forging situation could be evaluated using the Ergonomic Assessment Worksheet. In the experimental study, gripping force measurements and calorie measurements were used to determine the impact of handling the forging tongs on the forging employees. The results show that the use of the new ergonomically optimized forging tongs can lead to a significant physical relief for the forging employees. The knowledge gained from the ergonomically developed concepts can also be transferred in other industries. [ABSTRACT FROM AUTHOR]

Precise metal parts are manufactured using cold forged screw forming, but this method has drawbacks such as material damage and the possibility of imprecise parts. To ensure the accuracy and quality of parts, it is crucial to analyze and predict the forging force in this process. There are various methods to predict the forging force including laboratory testing, numerical simulation techniques, and simulation techniques. To provide forging information that cannot be measured by forging-forming machines, we simulated the nut-forming process based on actual manufacturing conditions using SolidWorks (v2020) with DEFORM-3D (v6.1). The results showed that the performance of the prediction of forging force specifications by the currently available nut-forming machines was improved by 8−20%. As the product becomes larger, the difference in forging force also increases proportionally. This research result, combined with appropriate experimental analysis, can be used as parameter controls for manufacturers in the future implementation of smart manufacturing. [ABSTRACT FROM AUTHOR]

The results of the study of the influence of multi-axial isothermal forging on the microstructure and martensitic transformation in a Ni58Mn18Ga24 alloy have been presented. Forging is performed in two stages: the first stage is forging at 700°C by four passes with true strain e ≈ 1.64; the second stage is forging at 500°C by one pass with e ≈ 0.24. The forging deformation results in the transformation of the original equiaxed-grain structure. No new grains are formed after the first stage of treatment. New recrystallized grains in a very negligible extent begin to be observed only after the second stage of deformation. Probably, at the first stage, the mechanism of fragmentation of the grain structure is not started due to an insufficient density of defects upon the deformation at 700°C. The characteristic temperatures of martensitic transformation are shifted after forging to the low temperature region. The anharmonic change in the sample length is observed in the region of martensitic transformation for the both treated states. In general, this indicates a low level of defect density and internal stresses in the sample. [ABSTRACT FROM AUTHOR]

This article discusses the results of our research into the effect of elongation on the welding of internal metallurgical discontinuities for two different geometrical shapes of a model feedstock of a selected magnesium alloy. Model discontinuities, specifically those of the metallurgical void type, were placed in various local zones of the modelled feedstock to check the influence of their location on their welding. The numerical modelling was carried out using the Forge®NxT2.1 application based on the finite element method. The results of the numerical tests were verified in laboratory conditions using the Gleeble simulator of metallurgical processes. Based on this research, it was found that the geometric shape of the feedstock material and the location of internal metallurgical discontinuities have a significant impact on the welding of discontinuities. The optimal values of the main process parameters of the elongation operation in flat dies were also determined for use in individual forging stages in order to eliminate internal metallurgical discontinuities. On the basis of the numerical studies carried out and their verification under laboratory conditions, it was concluded that a relative draft equal to 35% should be applied to weld the metallurgical discontinuities, which would result in a favorable hydrostatic pressure distribution within the discontinuities. [ABSTRACT FROM AUTHOR]

This paper focused on determining the increased tendency of cracking after the die forging process of high nickel and chromium steel. The increase in carbon content in austenitic nickel–chromium steel promoted the tendency of valve forgings to forging intergranular crack on the valve head. Attention was paid to issues related to the chemical composition of the material to be considered when hot forming nickel–chromium steel components. Optical and scanning electron microscopies were used to examine the microstructure and fracture features of the samples removed from a fractured valve head. The embrittlement was due to microcavity formation at grain boundaries. Creep theory at grain boundaries was used to explain crack formation. The tensile behavior was interpreted from the evolution of the microstructure during deformation and referred to intermediate brittleness to explain the effect of carbon. It was found that the increased carbon content of the nickel–chromium steel and the strong undercooling observed at the edges of the valve head are factors that promote a reduction in grain boundary cohesion and enhance intermediate temperature embrittlement. Finally, it was found that the formation of a heterogeneous structure manifested by the presence of grain boundary M23C6-type carbides in the austenitic matrix was most likely related to the occurring brittleness. [ABSTRACT FROM AUTHOR]

Background: Metal screws are commonly used for fracture fixations. However, the high modulus of elasticity relative to bones and releasing metallic ions by the metal screw needed a second surgery to remove the implant after the healing period. Furthermore, the removal of metal screws following the healing of the bone is a serious problem that can lead to refracture due to the presence of holes in the screw. Bioresorbable screws can overcome most of the problems associated with metallic screws which motivated research on manufacturing nonmetallic screws. Methods: In this study, three-layer poly L-lactic acid/bioactive glass composite screws were manufactured according to functionally graded material theory, by the forging process. All of the physical and chemical parameters in the manufacturing stages from making composite layers to the forging process were optimized to obtain suitable mechanical properties and durability off the screw in load-bearing positions. Results: The tri-layer composite screw with unidirectional, ±20° angled, and random fibers orientation from core to shell shows a flexural load of 661.5 ± 20.3 (N) with a decrease about 31% after 4-week degradation. Furthermore, its pull-out force was 1.8 ± 0.1 (N) which is considerably more than the degradable polymeric screws. Moreover, the integrity of the composite screws was maintained during the degradation process. Conclusions: By optimizing the manufacturing process and composition of the composite and crystallinity, mechanical properties (flexural, torsion, and pull-out) were improved and making it a perfect candidate for load-bearing applications in orthopedic implants. Improving the fiber/matrix interface through the use of a coupling agent was also considered to preserve the initial mechanical properties. The manufactured screw is sufficiently robust enough to replace metals for orthopedic load-bearing applications. [ABSTRACT FROM AUTHOR]

Forgings are produced in several process steps, the so-called forging sequence. The design of efficient forging sequences is a very complex and iterative development process. In order to automate this process and to reduce the development time, a method is presented here, which automatically generates multi-stage forging sequences for different forging geometries on the basis of the component geometry (STL file). The method was developed for closed die forging. The individual modules of this forging sequence design method (FSD method) as well as the functioning of the algorithm for the generation of the intermediate forms are presented. The method is applied to different forgings with different geometrical characteristics. The generated forging sequences are checked with FE simulations for the quality criteria form filling and freedom from folds. The simulation results show that the developed FSD method provides good approximate solutions for an initial design of forging sequences for closed die forging in a short time. [ABSTRACT FROM AUTHOR]