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Artykuły w czasopismach na temat "Hot metal forming"
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Liu, Cai-yi, Yan Peng, Ling Kong, Lu-han Hao i Ren Zhai. "Hot forming with a nonuniform temperature field using die partition cooling". Metallurgical Research & Technology 116, nr 6 (2019): 613. http://dx.doi.org/10.1051/metal/2019044.
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High strength steel hot forming technology plays an important role in achieving lightweight vehicles, improving the safety of vehicles. The tensile strength of the blank formed by traditional hot forming process is as high as 1500–2000 MPa, the strength of the formed blank is high, but the elongation is usually low and comprehensive mechanical property is not high. In this article, the process control of material gradient properties hot forming technology is summarized through the analysis of strengthening mechanism of gradient distribution hot forming technology. Based on the traditional hot forming technology, a new hot forming technology based on partition cooling to achieve material property gradient distribution is proposed. By changing the cooling rate of blank in different zones is different, and the gradient distribution of material properties is finally obtained. The DEFORM is used to analyze the hot forming process of the blank under the nonuniform temperature field of the partition cooling. A set of partition cooling hot forming die was designed independently to verify the experimental results. The evolution mechanism of microstructure and its effect on material properties during hot forming under nonuniform temperature field with partition cooling were revealed.
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Beynon, J. H. "Tribology of hot metal forming". Tribology International 31, nr 1-3 (styczeń 1998): 73–77. http://dx.doi.org/10.1016/s0301-679x(98)00009-7.
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Ma, Ning, Ping Hu i Zong Hua Zhang. "Research on a New Type of Metal Composite Material in Hot Forming and its Application". Advanced Materials Research 156-157 (październik 2010): 582–91. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.582.
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A new type of metal composite material can be manufactured by controlling heating temperature and designing the layout of cooling pipes in hot forming process of ultra high strength steel. The yield strength of this type of metal material varies from 380 MPa to 1000 MPa continuously, and its strength limitation varies from 480 MPa to 1600 MPa continuously. In this new hot forming technology, boron steel named as 22MnB5 is stamped by one-step process of hot forming to obtain the metal composite material and manufacture the part consisting of the metal composite at the same time. The hot forming technology of U-shaped part consisting of the metal composite material is provided. Then the microstructure of the U-shaped metal composite material is analyzed and the tensile test is also implemented. The experimental results show the material properties have the characteristics of continuous distribution along the main direction of energy absorption during crash process, which indicates the feasibility of hot forming technology of the metal composite material. The top-hat thin-wall structure consisting of U-shaped metal composite material is employed to analyze the crashworthiness of the new type of metal composite material. By distributing the single phase material of U-shaped composite part properly, the energy absorption ability is increased by 58.7% and the crash force is decreased by 23.4%, which indicate the new type of metal composite material has the comprehensive performance of every single phase material. So the metal composite is a good alternative material in application of crash resistance.
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Bambach, Markus, Irina Sizova i Aliakbar Emdadi. "Towards Damage Controlled Hot Forming". Applied Mechanics and Materials 885 (listopad 2018): 56–63. http://dx.doi.org/10.4028/www.scientific.net/amm.885.56.
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Metal forming processes may induce internal damage in the form of voids in the workpiece under unfavorable deformation conditions. Controlling the amount of damage induced by metal forming operations may increase service performance of the produced parts. Damage is crucial in high-performance components of limited workability such as jet engine turbine blades. Recent developments have introduced forged titanium aluminides into commercial jet engines. Titanium aluminides are lightweight intermetallic compounds with excellent creep properties but very limited ductility. Their low workability requires isothermal forging at slow strain rates, which is typically kept constant in the process. This work explores the possibility of increasing the ram speed during the process so that the process time is reduced while the amount of damage introduced into the workpiece is controlled. The results show that a 25% reduction in process time seems viable without increase in damage by solving an optimal control problem, in which the ram speed profile is determined off-line by minimization.
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Geindreau, Christian, Didier Bouvard i Pierre Doremus. "Constitutive behaviour of metal powder during hot forming." European Journal of Mechanics - A/Solids 18, nr 4 (lipiec 1999): 597–615. http://dx.doi.org/10.1016/s0997-7538(99)00101-1.
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Yu, Hai Yan, Li Bao, You Zhi Deng i Wei Cao. "Forming Response of Ultra High Strength Steel Sheet to Stamping Speed during Hot Forming". Advanced Materials Research 160-162 (listopad 2010): 123–29. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.123.
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Stamping speed is an important parameter in sheet metal forming especially in hot forming. In this study, hot forming of a U-shaped part made of ultra high strength boron steel (22MnB5) sheet is simulated with solid elements. The mechanical properties of 22MnB5 steel sheet and the key process parameters are introduced in detail. Emphasis is laid on the forming response of the boron steel sheet to stamping speeds of 3.25m/s, 0.325m/s and 0.0325m/s. The mechanism of stamping speed acting on hot formability and temperature field of the stamped part is analyzed. It is demonstrated that stamping speed affects both formability and the heat transferred from blank to tools and to environment during hot forming. And the coupling effect of material properties, the heat produced during plastic deformation and heat boundary condition decides the formability and temperature field. An appropriate stamping speed is more important for hot forming than that for common cold forming.
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Xu, Yong, Xiu-Wen Lv, Yun Wang, Shi-Hong Zhang, Wen-Long Xie, Liang-Liang Xia i Shuai-Feng Chen. "Effect of Hot Metal Gas Forming Process on Formability and Microstructure of 6063 Aluminum Alloy Double Wave Tube". Materials 16, nr 3 (29.01.2023): 1152. http://dx.doi.org/10.3390/ma16031152.
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The hot metal gas forming process can significantly improve the formability of a tube and is suitable for the manufacturing of parts with complex shapes. In this paper, a double wave tube component is studied. The effects of different temperatures (400 °C, 425 °C, 450 °C and 475 °C) and different pressures (1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa and 3 MPa) on the formability of 6063 aluminum alloy tubes were studied. The influence of hot metal gas forming process parameters on the microstructure was analyzed. The optimal hot metal gas forming process parameters of 6063 aluminum alloy tubes were explored. The results show that the expansion rate increases with the increase in pressure. The pressure affects the deformation of the tube, which in turn has an effect on the dynamic softening of the material. The expansion rate of parts also increases with the increase in forming temperature. The increased deformation temperature is beneficial to the dynamic recrystallization of 6063, resulting in softening of the material and enhanced deformation uniformity between grains, so that the formability of the material is improved. The optimum hot metal gas forming process parameters of 6063 aluminum alloy tubes are the temperature of 475 °C and the pressure of 2.5 MPa; the maximum expansion ratio is 41.6%.
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Rana, Radhakanta, Theo Kop, Peter Beentjes i Ellen van der Aa. "Low Temperature Hot Press Forming of a Zinc Coated Third Generation Advanced High Strength Steel". Materials Science Forum 1105 (29.11.2023): 225–30. http://dx.doi.org/10.4028/p-udks6s.
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A 7 wt.% Mn steel was designed and was cast and processed to 1.5 mm sheets. The sheets were continuous annealed and coated with a Zn alloy by hot dip galvanizing before subjecting them to hot press forming cycles. The final microstructure was characterized by ultrafine ferrite grains and a high fraction of retained austenite. Excellent combinations of in-service strength-ductility-bendability were achieved for hot forming in the temperature range of 530-675 °C. The use of the low temperature hot forming minimized the liquid metal embrittlement induced cracking with Zn coating during hot forming and spot welding. Various application properties such as oxidation resistance, corrosion resistance, and springback were found at optimum levels for hot forming at 675 °C.
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Sana, Guillaume, Alain Petiot i Arnaud Giraudet. "Hot Forming and Superplastic Forming: Presses Evolution and New Applications in the Aerospace Industry". Materials Science Forum 838-839 (styczeń 2016): 563–67. http://dx.doi.org/10.4028/www.scientific.net/msf.838-839.563.
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ACB (France) and its sister company Cyril Bath (USA) have a long experience in the fields of hydraulic presses and metal forming for the aerospace industry. This experience is particularly focused on the manufacturing of structural and engines parts. The purpose of this presentation is to show how the combination of both activities in the fields of Hot Forming/Sizing and Superplastic Forming results in continual progress and how recent evolution open new fields of applications. First, both processes will be shortly introduced. The advantages of Hot Forming, Superplastic forming and Diffusion Bonding technologies will be demonstrated regarding current customer’s requirements. To conclude an overview of on-going research programs will be made to present strong advantages of dual presses combining Hot Forming and Superplastic processes.
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Müller, Roland, i André Mosel. "Characterisation of Tool Coatings for Press Hardening". Advanced Materials Research 966-967 (czerwiec 2014): 259–69. http://dx.doi.org/10.4028/www.scientific.net/amr.966-967.259.
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Hot sheet metal forming is gaining in importance in many fields, because of its capability to produce more complex components than possible with cold forming. Hot forming is also used to influence the final material properties with the hot forming of manganese-boron steels being a good example. One of the major challenges in hot forming is the tribological conditions between the tool and sheet material at the required high temperatures. This article will discuss the influence of different tool material coatings, ranging from PVD to mechanically bonded ceramic coatings, on the tribological conditions during forming. It will also shed light on how these coatings influence the heat transfer between the component ́s material and the tool material.
Rozprawy doktorskie na temat "Hot metal forming"
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Odenberger, Eva-Lis. "Concepts for hot sheet metal forming of titanium alloys /". Luleå : Department of Applied Physics and Mechanical Engineering, Division of Solid Mechanics, Luleå University of Technology, 2009. http://www.avhandlingar.se/avhandling/167c433b06/.
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Trull, Mikhail. "Modelling of oxide failure in hot metal forming operations". Thesis, University of Sheffield, 2003. http://etheses.whiterose.ac.uk/10262/.
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Oxide scale can affect many aspects of hot metal forming operations, such as heat transfer, friction and the final surface finish of the rolled product. Surface oxide scale is always present on the steel slab and sometimes on cold rolls. Therefore, the study of the thermo-mechanical behaviour of oxide scale, particularly under conditions as close as possible to the steel manufacturing process is very important. In order to undertake a detailed study of oxide scale behaviour, several hightemperature testing techniques were applied. First, high-temperature tensile tests were carried out to investigate the brittle fracture and cracking of the surface oxide scales. Second, high-temperature compression tests were developed and the results obtained revealed many different failure mechanisms that are present in the compressed oxide scale. Finally, a tensile-compressive test was developed and performed under thermal conditions which were as close as possible to hot rolling. The best results in the understanding of oxide scale failure were achieved by closely linked combination of laboratory testing and measurements coupled with detailed finite element analysis. A close microstructural examination of the morphology of oxides was carried out after each experiment and finite element modelling was performed. The three-dimensional finite element simulations helped to improve the interpretation of the thermo-mechanical testing and to obtain more accurate heat transfer and stress-strain relationships. In this work the following thermo-mechanical failure modes of the oxide scales were observed and investigated: brittle fracture (through-thickness cracking, blister failure), indications of plastic behaviour (arrested cracks, unbroken top layers of the oxide scale) and a sticking effect (equivalent to the mill pick-up).
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Schonauer, M. "Unified numerical analysis of cold and hot metal forming processes". Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638778.
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A decoupled thermo-mechanical model which includes elastic behaviour is cast into a finite element formulation, which is numerically unified for simulation of both cold and hot metal forming processes. Computational attention has been focused on the mechanical aspects, where the elasto-plastic constitutive law is utilized for cold (practically rate-independent) regimes, while metalurgically sound high temperature interpolation function are employed in the computational framework of Perzyna type elasto-viscoplasticity for hot (rate-dependent) processes. Introduction of a logarithmic strain based finite strain model within the context of a geometrically nonlinear assumed strain method characterizes the numerical treatment of incompressibility at large elastic-inelastic deformations. The plastic theory of quasi-static friction with a non-associated slip rule is employed for general interface frictional contact condition. The contact constraints are imposed pointwise at the specimen (slave) boundary nodes. The assumption of rigid tools is made and nonlinear tool (master) segment geometry describing the contact kinematics is introduced. Consistent linearization in all aspects of algorithmic development provides robust and quadratically convergent solutions. After the capabilities of the model in representing physically realistic behaviours are rigorously tested in plane strain localization and axisymmetric necking benchmark tests, several numerical examples are presented, where simulations of both cold and hot metal forming processes including spike forming, industrial forging, flat rolling, tube expansion and thin sheet forming are performed. The robust and consistent numerical treatment of the thermo-mechanical theoretical formulations ensures generality and future upgradability of the model.
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Michieletto, Francesco. "Innovative forming processes of aluminium alloys sheets and tubes at elevated temperature". Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424956.
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In the last two decades the international community has been looking for solutions to preserve the environment, and in particular the atmosphere, from the CO2 emissions through the car exhausts, considered one of the main responsible of the greenhouse effect and, therefore, of the Earth temperature increase. Rules and limits were fixed in the 1997 with the Kyoto Protocol that entered in force in 2005, by which the international community signed the legal responsibility for producing vehicles with CO2 emission limited to 95g/km to be reached in 2020. The production of cars using lightweight materials can represent an optimal solution because the lower weight means lower energy consumption. Therefore, the automotive companies are now investigating the feasibility of producing parts made of lightweight materials to replace conventional steels for the car chassis and body-in-white components, but without decreasing the passenger safety.
High resistance steels and aluminium alloys have demonstrated to be the best solution thanks to their low density, high corrosion resistance and excellent stiffness-to-weight ratio. In case of use of aluminium alloy sheets and tubes, it is possible to reduce the car weight of about 15–20 % with also a consequent weight reduction of all the connected vehicle parts and therefore a substantial reduction of the pollutant exhausts.
The main limit of light alloys is the poor formability and the high springback exhibited during room temperature deformation. Temperature assisted processes have proven to increase material formability: Superplastic and Quick Plastic Forming, already used for shaping aluminium sheets, have shown a relevant increase in the material formability allowing to form very complex parts but are extremely expensive due to the very long process times, therefore not applicable for mass production. On the other hand, cold and warm hydroforming processes, nowadays at the state-of-the-art for shaping hollow components, exhibit very high initial investment cost due to the high pressure of the fluid used as deformable mean and to the high tons presses needed for keeping the dies closed during the process. Moreover, a strict forming temperature limit is fixed by the fluid boil and burst temperatures, which may limit the material formability.
In this research work, innovative forming processes were investigated to prove the feasibility of shaping aluminium sheets and tubes at high temperature, exceeding the limits of the already available process technologies. In particular, the Hot Stamping (HS) technology was applied to form 5xxx and 6xxx series aluminium alloys proving the capability of stamping an automotive component on a hot stamping industrial plant, and thus validating the laboratory tests results. An experimental apparatus able to work with the innovative technology of the Hot Metal Gas Forming (HMGF) process was designed and developed to form aluminium alloy tubes. In doing so, resistance heating was used as heating system and cold air in pressure was used to bulge-up the tubes during the process. The formability of different 6xxx series aluminium alloys tubes was investigated by means of free bulging tests and, afterwards, shaping component inside a die, evaluating the influence of the most important process parameters. Finally, in collaboration with an industrial company, the shaping of an aesthetic component with also the evaluation of the surface appearance was carried out demonstrating the applicability of the new process to form an industrial part.Negli ultimi decenni, la comunità internazionale è alla continua ricerca di provvedimenti per salvaguardare l’atmosfera e l’ambiente terrestre. In campo automobilistico e dei trasporti la produzione di biossido di carbonio dai gas di scarico delle autovetture, meglio conosciuto come CO2, è ritenuto tra i maggiori responsabili del rafforzamento dell’effetto serra e dunque dell’innalzamento del clima terrestre. Per porre un concreto rimedio e regolamentare l’efficienza sul consumo medio di un autoveicolo, con il protocollo di Kyoto stipulato nel 1997 ed entrato in vigore nel 2005, la comunità internazionale si è impegnata legalmente alla produzioni di veicoli in grado di rispettare il limite di emissione di 95 g di CO2 per kilometro entro l’anno 2020. L’alleggerimento complessivo di un automobile è sicuramente tra le soluzioni più immediate per la riduzione delle particelle inquinanti, in quanto veicoli più leggeri richiedono minore forza motrice e di conseguenza minore consumo di energia. Per questo motivo le compagnie automobilistiche negli ultimi anni sono alla ricerca di materiali innovativi per sostituire l’acciaio che comunemente è impiegato per la realizzazione di telai e parti di carrozzeria, senza pregiudicare la sicurezza dei passeggeri. Gli acciai alto resistenziali ma soprattutto le leghe leggere, hanno dimostrato essere delle ottime alternative grazie alle loro proprietà di bassa densità, resistenza alla corrosione, ed ottimo rapporto rigidezza-peso. Con l’utilizzo di parti stampate ma anche di elementi tubolari in lega di alluminio il peso medio della sola scocca di una vettura può essere ridotto del 15 – 20 %, portando ad un conseguente ridimensionamento di tutte gli organi connessi ed ad una sostanziale riduzione delle emissioni dannose. La principale limitazione nella lavorazione delle leghe di alluminio è la loro scarsa attitudine a subire deformazione plastica a temperatura ambiente collegata oltretutto ad un elevato ritorno elastico. Per far fronte a questa problematica, numerosi processi innovativi utilizzanti alta temperatura sono stati o sono tuttora in fase di studio con l’obiettivo principale di incrementare la formabilità del materiale. I confermati processi di deformazione di lamiera di alluminio quali Superplastic Forming e Quick Plastic Forming, hanno dimostrato sicuramente un vantaggio in termini di formabilità riuscendo oltretutto a generare parti complesse, ma sono d’altro canto estremamente costosi e soggetti a tempi molto lunghi di processo, per cui non applicabili per produzioni in larga scala. L’idroformatura a freddo e a tiepido, invece, che rappresenta l’attuale tecnologia all’avanguardia per la sagomatura di parti cave, oltre a necessitare di elevati costi iniziali connessi alle elevate pressioni del fluido necessarie per la deformazione e alle presse ad alto tonnellaggio richieste per la chiusura degli stampi durante l’iniezione del liquido stesso, presenta severi limiti nella temperatura massima di processo. Infatti le emulsioni acqua olio generalmente impiegate come mezzo deformante risultano infiammabili al di sopra del campo tiepido per l’alluminio, limitando dunque il range termico utilizzabile per il processo e di conseguenza la formabilità del materiale. In questo lavoro di ricerca sono stati studiati processi innovativi per la produzione di componenti di alluminio in lamiera e tubolari che superassero i limiti di processo delle attuali tecnologie produttive. In particolare la tecnologia dello stampaggio a caldo (Hot Stamping), oggigiorno applicata agli acciai alto resistenziali, è stata applicata con successo su lamiere di alluminio serie 5xxx e 6xxx, e validata con test industriali eseguiti su una vera linea di stampaggio producendo un componente automobilistico. Inoltre è stato realizzato e sviluppato un prototipo in grado di operare con la tecnologia innovativa del Hot Metal Gas Forming, che utilizza gas in pressione invece di fluidi per deformare componenti tubolari al alta temperatura. Prove di formabilità su tubi di alluminio serie 6xxx, ma anche la realizzazione di componenti in stampo, hanno permesso inoltre lo studio di numerosi aspetti critici per il processo. In fine, la sagomatura di un componente industriale in collaborazione con una azienda, curando oltretutto la qualità estetica del formato, ha permesso di verificare l’applicabilità e l’efficacia di questo processo anche a livello industriale.
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Billur, Eren. "Fundamentals and Applications of Hot Stamping Technology for Producing Crash-Relevant Automotive Parts". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366243664.
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Abachi, Siamak. "Wear Analysis Of Hot Forging Dies". Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605706/index.pdf.
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WEAR ANALYSIS OF HOT FORGING DIES
ABACHI, Siamak
M. S., Department of Mechanical Engineering
Supervisor: Prof. Dr. Metin AKKÖK Co-Supervisor: Prof. Dr. Mustafa lhan GÖ
KLER December 2004, 94 pages The service lives of dies in forging processes are to a large extent limited by wear, fatigue fracture and plastic deformation, etc. In hot forging processes, wear is the predominant factor in the operating lives of dies. In this study, the wear analysis of a closed die at the final stage of a hot forging process has been realized. The preform geometry of the part to be forged was measured by Coordinate Measuring Machine (CMM), and the CAD model of the die and the worn die were provided by the particular forging company. The hot forging operation was carried out at a workpiece temperature of 1100°
C and die temperature of 300°
C for a batch of 678 on a 1600-ton mechanical press. The die and the workpiece materials were AISI L6 tool steel and DIN 1.4021, respectively. The simulation of forging process for the die and the workpiece was carried out by Finite Volume Method using MSC.SuperForge. The flow of the material in the die, die filling, contact pressure distribution, sliding velocities and temperature distribution of the die have been investigated. In a single stroke, the depth of wear was evaluated using Archard&rsquo
s wear equation with a constant wear coefficient of 1¥
10-12 Pa-1 as an initial value. The depth of wear on the die surface in every step has been evaluated using the Finite Volume simulation results and then the total depth of wear was determined. To be able to compare the wear analysis results with the experimental worn die, the surface measurement of the worn die has been done on CMM. By comparing the numerical results of the die wear analysis with the worn die measurement, the dimensional wear coefficient has been evaluated for different points of the die surface and finally a value of dimensional wear coefficient is suggested. As a result, the wear coefficient was evaluated as 6.5¥
10-13 Pa-1 and considered as a good approximation to obtain the wear depth and the die life in hot forging processes under similar conditions.
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Haliscelik, Murat. "Elastic-plastic Finite Element Analysis Of Semi-hot Forging Dies". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610542/index.pdf.
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Semi-hot or warm forging is an economical alternative to the conventional forging processes by combining advantages of hot and cold forging processes.
In this study, a new forging process sequence and design of the preform die for a part which has been produced by hot forging are proposed to be produced by semi-hot forging. Thermo-mechanical finite element analyses are performed over the stages of forging process. The billet and the dies are modeled as elastic-plastic bodies. Effects of preform die geometry on the die stresses and the forging load are investigated using finite element method. Comparison of the results obtained by using two different commercial finite element analysis programs is done for semi-hot and hot forging temperature ranges. The forging temperatures are determined for the particular part and the experiments are conducted by using the 1000 ton forging press. The parts are produced without any defects and material wastage in the form of flash is reduced. The numerical results are also compared with the experimental results and a good agreement is achieved.
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Pallikonda, Mahesh Kumar Pallikonda. "FORMING A METAL MATRIX NANOCOMPOSITE (MMNC) WITH FULLY DISPERSED AND DEAGGLOMERATED MULTIWALLED CARBON NANOTUBES (MWCNTs)". Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1503937490966191.
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Turetta, Alberto. "Investigation on thermal, mechanical and microstructural properties of quenchenable high strenght steels in hot stamping operations". Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425096.
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Sheet metal working operations at elevated temperature have gained in the last years even more importance due to the possibility of producing parts characterized by high strength-to-mass ratio. In particular, the hot stamping of ultra high strength quenchenable steels is nowadays widely used in the automotive industry to produce body-in-white structural components with enhanced crash resistance and geometrical accuracy. The optimization of the process, where deformation takes place simultaneously with cooling, and of the final component performances requires the utilization of FE-based codes where the forming and quenching phases have to be represented by fully thermo-mechanical-metallurgical models. The accurate calibration of such models, in terms of material behaviour, tribology, heat transfer, phase transformation kinetics and formability, is therefore a strong requirement to gain reliable results from the numerical simulations and offer noticeable time and cost savings to product and process engineers.
The main target of this PhD thesis is the development of an innovative approach based on the design of integrated experimental procedures and modelling tools in order to accurately investigate and describe both the mechanical and microstructural material properties and the interface phenomena due to the thermal and mechanical events that occur during the industrial press hardening process.
To this aim, a new testing apparatus was developed to evaluate the influence of temperature and strain rate on the sheet metal elasto-plastic properties and to study the influence of applied stress and strain of the material phase transformation kinetics. Furthermore, an innovative experimental setup, based on the Nakazima concept, was designed and developed to evaluate sheet formability at elevated temperature by controlling the thermo-mechanical parameters of the test and reproducing the conditions that govern the microstructural evolution during press hardening. This equipment was utilized both to determine isothermal forming limit curves at high temperature and to perform a physical simulation of hot forming operations. Finally, a thermo-mechanical-metallurgical model was implemented in a commercial FE-code and accurately calibrated to perform fully coupled numerical simulations of the reference process.
The material investigated in this work is the Al-Si pre-coated quenchenable steel 22MnB5, well known with the commercial name of USIBOR 1500P’®, and the developed approach proves to be suitable to proper evaluate high strength steels behaviour in terms of mechanical, thermal and microstructural properties, and to precisely calibrate coupled numerical models when they are applied to this innovative manufacturing technology.
The work presented in this thesis has been carried out at DIMEG labs, University of Padova, Italy, from January 2005 to December 2007 under the supervision of Prof. Paolo F. Bariani.
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Soranansri, Panuwat. "Tribological behavior in hot forming of aluminum alloy : tribological performance of commercial PVD coatings and mechanisms of aluminum transfer". Electronic Thesis or Diss., Valenciennes, Université Polytechnique Hauts-de-France, 2025. https://ged.uphf.fr/nuxeo/site/esupversions/59dae705-f61e-4502-b722-6abf28311853.
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Les objectifs de cette thèse de doctorat étaient de caractériser l’efficacité des revêtements de surface développé pour lutter contre les problèmes de transfert de matière rencontrés lors de la mise en forme de l’aluminium à chaud, et d'étudier ces mécanismes de transfert. Le matériau utilisé était un alliage d'aluminium AA 6082-T6, largement employé dans la fabrication de composants automobiles.Le test de Compression-Translation à chaud (WHUST) a été retenu comme tribomètre principal pour cette étude. Afin de contrôler précisément les températures des essais, un dispositif miniaturisé du WHUST a été conçu afin être intégré dans la chambre chauffante de la plateforme Bruker UMT TriboLab. Les tests préliminaires avec ce nouvel appareil ont montré un empilement significatif de matière devant le contacteur. De nouvelles équations analytiques ont donc été développées pour identifier le coefficient de frottement de Coulomb (COF) et le facteur de frottement (loi de Tresca) en tenant compte de cet empilement de matière.Le WHUST a ensuite été utilisé pour évaluer les performances tribologiques de trois revêtements PVD commerciaux : un AlCrN, un TiAlN et un Arc-DLC. Les expériences ont été menées sans lubrifiant, à des températures variant de 300 °C à 500 °C, sous des pressions de contact comprises entre 40 et 100 MPa, avec une vitesse de glissement égale à 0,5 mm/s. Les résultats ont montré que le revêtement Arc-DLC était plus efficace que les revêtements AlCrN et TiAlN pour atténuer les problèmes de transfert d’aluminium. En particulier, le revêtement Arc-DLC provoquait moins d'adhésion et moins de transfert d'aluminium, notamment lors du début du glissement. Ces résultats ont été confirmés par des essais sous des pressions de contact plus élevées, réalisés à l’aide l’essai de forgeage en T à chaud (HVGCT).Dans la deuxième partie de cette thèse, le revêtement Arc-DLC a été sélectionné pour étudier en détail les mécanismes de transfert d’aluminium sur les outils de mise en forme. Des essais ont été réalisés avec une courte distance de glissement (2 mm) pour examiner les premières étapes du transfert d’aluminium, tandis que des tests avec une distance de glissement de 38 mm ont permis d’étudier l’évolution du transfert. Les expériences ont été conduites aux mêmes températures d’essai (300-500°C), avec deux vitesses de glissement différentes, 0,5 mm/s et 5,0 mm/s, et toujours sans lubrifiant. Les topographies de surface et les images SEM prises le long de la piste de frottement ont montré que le transfert d'aluminium se produit en deux étapes principales : une phase initiale principalement due au labourage mécanique, suivie d'une phase de croissance dominée, en fonction des températures et des vitesses de glissement, par du labourage mécanique ou par de l'adhésion.Dans la dernière partie de cette thèse, l'apprentissage automatique (ML) a été utilisé pour étudier les mécanismes de transfert d’aluminium. Les topographies de surface et les images SEM prises le long de la piste de frottement ont été analysées. Elles ont été classifiées à l’aide de cinq algorithmes d’apprentissage automatique simples et d'une architecture de réseau neuronal convolutif (CNN) personnalisée. Il a été démontré que le ML appliqué aux données topographiques et le CNN appliqué aux images SEM permettaient tous deux d’identifier les modes d’usure avec précisionThe aims of this PhD thesis were to find effective surface coatings to prevent the material transfer issue and to study the mechanisms of material transfer in the hot forming of aluminum alloy. The workpiece material was AA 6082-T6 aluminum alloy, which is widely used to produce automotive components.The warm and hot upsetting sliding test (WHUST) was selected as the main tribometer in this study. To control the testing temperatures precisely, a scaled-down apparatus of the WHUST was designed to integrate into the heating chamber of the Bruker UMT TriboLab platform. The preliminary experiments of the new apparatus found that the pile-up material significantly occurred in front of the contactor due to the high friction at the interface and the deformation characteristic of the aluminum alloy at high temperatures. From this point, the pile-up material was considered as a new parameter in analytical equations used to identify the Coulomb coefficient of friction (COF) and the shear friction factor.The new apparatus of the WHUST was then used to evaluate the tribological performance of three commercial PVD coatings: AlCrN, TiAlN, and Arc-DLC. The experiments were performed at temperatures between 300˚C and 500˚C, at 0.5 mm/s of sliding speed under non-lubrication contact conditions. Those conditions led to the mean contact pressure between 40 MPa and 100 MPa. The results showed that the Arc-DLC coating had better efficiency in alleviating the aluminum transfer issue than the AlCrN and TiAlN coatings. The Arc-DLC coating caused less adhesive to the aluminum alloy and less transferred aluminum, especially in the initial period. Moreover, these findings were consolidated under higher contact pressure by using the hot V-groove compression test (HVGCT).Following that, the Arc-DLC coating was selected to study the mechanisms of aluminum transfer on the forming tool in detail. The WHUST was performed with the specific short sliding distance (2 mm) to investigate the initial stage of aluminum transfer, while the full sliding distance (38 mm) was used to examine the evolution of aluminum transfer. The experiments were conducted at the same testing temperatures with two different sliding speeds, 0.5 mm/s and 5.0 mm/s, under non-lubrication contact conditions. It was found that the aluminum transfer in the initial stage was mainly caused by mechanical plowing. Then, during the grow-up stage, the aluminum transfer was dominated by mechanical plowing and/or adhesive bonding, depending on the testing temperatures and the sliding velocities. Additionally, the different transfer mechanisms caused dissimilar COFs, surface characteristics along the friction track of the specimen, as well as transferred aluminum.In the last part of this PhD thesis, Machine Learning (ML) was involved to study the mechanisms of aluminum transfer. The previous part found that the wear characteristics along the friction track could be a significant indicator to differentiate the transfer mechanisms. Thus, the surface topographies and the SEM images along the friction track were used to classify by five simple ML algorithms and a custom Convolutional Neural Network (CNN) architecture, respectively. It was proved that the ML with topographic data and the CNN with SEM image data had the potential to identify the wear mode accurately
Książki na temat "Hot metal forming"
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Hu, Ping, Ning Ma, Li-zhong Liu i Yi-guo Zhu. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming. London: Springer London, 2013. http://dx.doi.org/10.1007/978-1-4471-4099-3.
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Zhu, Jie. Study on microstructural evolution of stainless steel 316 and 304 during hot metal forming processes. Birmingham: University of Birmingham, 2002.
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Hu, Ping. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming: Analysis, Simulation and Engineering Applications. London: Springer London, 2013.
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Fedorenko, Mihail, Yuliya Bondarenko, Tamara Sanina, Tat'yana Duyun i Vladimir Duganov. Shaping processes and tools. ru: INFRA-M Academic Publishing LLC., 2024. http://dx.doi.org/10.12737/1214787.
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The issues of hot processing of materials are considered: foundry, metal forming, welding; forming tools; material processing by cutting, as well as plastic deformation methods and using electrophysical and electrochemical processing methods. Sections and topics accompany a large number of calculations that can be used both in practical classes and when performing independent work. Meets the requirements of the federal state educational standards of higher education of the latest generation. The textbook is intended for students studying the discipline "Processes of shaping and instrumentation". It can be used by students of various specialties of full-time and part-time education in the disciplines of "Shaping processes and operations", "Cutting tools".
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CHS2 Proceedings - Hot Sheet Metal Forming of High-Performance Steel. Association for Iron & Steel Technology, 2024.
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CHS2 2024 Proceedings - Hot Sheet Metal Forming of High-Performance Steel (digital). Association for Iron & Steel Technology, 2024.
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Ma, Ning, Ping Hu, Li-zhong Liu i Yi-guo Zhu. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming: Analysis, Simulation and Engineering Applications. Springer London, Limited, 2012.
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Ma, Ning, Ping Hu, Li-zhong Liu i Yi-guo Zhu. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming: Analysis, Simulation and Engineering Applications. Springer, 2014.
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Campbell, F. C., red. Metals Fabrication. ASM International, 2013. http://dx.doi.org/10.31399/asm.tb.mfub.9781627083089.
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Metals Fabrication: Understanding the Basics describes the practices, processes, and procedures used throughout industry to produce metal products and goods. It begins with a review of primary mill processes and the basic steps for making iron, steel, aluminum, and titanium. It then covers nearly every subsequent fabrication process, starting with casting followed by forging, forming, machining, heat treating, finishing, and coating as well as powder-metal part production. The book provides a thorough review of each process, discussing typical implementations, material requirements, design considerations, and common imperfections and defects. It also explains how heat, force, and power generated by production equipment alter the metallurgical and mechanical properties of work in process, bringing practical perspective to many fundamental concepts including solidification, deformation, residual stress, fracture mechanics, wear, and phase transformations. For information on the print version, ISBN 978-1-62708-018-7, follow this link.
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Fuertes, Jairo N., red. Working Alliance Skills for Mental Health Professionals. Oxford University Press, 2019. http://dx.doi.org/10.1093/med-psych/9780190868529.001.0001.
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The impetus for this book comes from years of teaching and supervising graduate-level students and my being asked by thoughtful students some variation of the following question: “How do I go about establishing the working alliance?” In this volume, the authors focus on the working alliance, specifically Bordin’s conceptualization of the working alliance, which emphasizes therapist–client agreement on the goals and tasks of treatment, and the existence of a trust and bond that is made between the therapist and client. A perusal of the literature on the working alliance reveals that hundreds of studies have been conducted on the topic. Given the popularity of Bordin’s working alliance and the considerable research that has been conducted about it, it is surprising to find that there is little published work about the skills that are used in sessions to establish and sustain it. To address this gap in the literature, the authors provide examples of in-session therapist interventions and behaviors that can guide the reader toward forming stronger alliances in therapy and, hopefully, better processes and outcomes in treatment.
Części książek na temat "Hot metal forming"
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Bertrand-Corsini, C., C. David, A. Bern, P. Montmitonnet, J. L. Chenot, P. Buessler i F. Fau. "A Three Dimensional Thermomechanical Analysis of Steady Flows in Hot Forming Processes. Application to Hot Flat Rolling and Hot Shape Rolling". W Modelling of Metal Forming Processes, 271–79. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1411-7_30.
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Hayashi, Kanji, Hideyuki Nikaido i Hideaki Furumoto. "Endless Hot Strip Rolling". W 60 Excellent Inventions in Metal Forming, 233–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-46312-3_36.
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Singh, Amarjeet Kumar, i K. Narasimhan. "Artificial Neural Network (ANN) Based Formability Prediction Model for 22MnB5 Steel under Hot Stamping Conditions". W Metal Forming Processes, 1–9. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003226703-1.
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Pietrzyk, M., i J. G. Lenard. "Thermal-Mechanical Modelling for Hot Rolling: Experimental Substantiation". W Modelling of Metal Forming Processes, 281–88. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1411-7_31.
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Beynon, J. H., A. R. S. Ponter i C. M. Sellars. "Metallographic Verification of Computer Modelling of Hot Rolling". W Modelling of Metal Forming Processes, 321–28. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1411-7_36.
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Hrycaj, P., D. Lochegnies, J. Oudin, J. C. Gelin i Y. Ravalard. "Finite Element Analysis of Two-Roll Hot Piercing". W Modelling of Metal Forming Processes, 329–36. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1411-7_37.
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Cescutti, J. P., E. Wey i J. L. Chenot. "Finite Element Calculation of Hot Forging with Continuous Remeshing". W Modelling of Metal Forming Processes, 207–16. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1411-7_23.
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Omori, Shunji, Hiroyuki Hino, Kanji Hayashi i Hideaki Furumoto. "Pair Cross Type Rolling Mill for Hot Rolling". W 60 Excellent Inventions in Metal Forming, 225–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-46312-3_35.
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Ikeda, Nobuhiro. "Non-graphite Water Soluble Lubricant for Hot Forging". W 60 Excellent Inventions in Metal Forming, 267–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-46312-3_41.
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Huskic, Adis, Mohammad Kazhai i Bernd-Arno Behrens. "Process-Integrated Heat Treatment of Hot Forged Components". W 60 Excellent Inventions in Metal Forming, 421–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-46312-3_65.
Pełny tekst źródłaStreszczenia konferencji na temat "Hot metal forming"
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Charles, J., D. Jobard, F. Dupoiron i D. Catelin. "Clad Plates an Economical Solution for Severe Corrosive Environments". W CORROSION 1988, 1–16. NACE International, 1988. https://doi.org/10.5006/c1988-88009.
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Abstract Cladding offers the strength and economy of one metal and the corrosion resistance of another. The paper present the cladding processes and the new developments in clad products. Austenoferritic stainless steels, superaustenitic stainless steels, alloy 825, alloy 625 and Hastelloy alloy C22 clad products are investigated. Metallurgical and corrosion resistance properties are presented. It is shown that clad metal and solid plates present similar corrosion resistance properties. Well defined hot forming heattreatment doesn't affect the properties of the material. Finally it is confirmed that cladding is a cost saving technology particulary for the high alloyed clad metals.
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URSINUS, Jonathan, Martin BONHAGE, Christoph BÜDENBENDER, Florian NÜRNBERGER, Eugen DEMLER i BerndArno BEHRENS. "Hot Forming of Cast Steel Cylinders". W METAL 2019. TANGER Ltd., 2019. http://dx.doi.org/10.37904/metal.2019.820.
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MAENO, Tomoyoshi. "Hot local compression and die quench ausforming of quenchable steel sheet". W Metal Forming 2024, 32–40. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-4.
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Abstract. Characteristics of hot local compression were investigated to apply hot stamping to a plate forging process. A heated quenchable steel sheet was locally compressed in a thickness direction and held with a punch at the bottom dead centre for die quenching. The effect of a forming temperature on reduction ratio and hardness was examined. Holding at the bottom dead centre improved the compression ratio due to plastic deformation during martensite transformation. Additionally, the quenched hardness of the locally compressed portion increased due to ausformig.
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ZHANG, Ruiqiang. "Experimental formability evaluation for aluminium alloy sheets under hot stamping conditions". W Metal Forming 2024, 90–99. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-10.
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Abstract. The process of Hot Form and Quench for aluminium alloys, known as HFQ®, has been developed and applied to manufacture lightweight, high-strength engineering panel components in the automotive industry. However, formability evaluation for the alloys under hot stamping conditions is challenging. In this study, a recently developed biaxial testing method has been applied to aluminium alloy AA6082 for formability evaluation at temperatures ranging from 440–510 °C and at a strain rate of 0.1 s-1. This method involves heating cruciform specimens via the resistance heating system in the Gleeble, and deforming them until fracture via a customised biaxial tensile rig which transfers a uniaxial force into biaxial forces. The location for welding thermocouples on cruciform specimen surface for temperature feedback control in the Gleeble is investigated. Furthermore, temperature nonuniformity within the gauge area of cruciform specimens is quantified, and biaxial tensile tests on the specimens are carried out under different conditions. Both the limit strains at the onset of necking and at fracture are determined, and their dependency on the deformation conditions is analysed. It is found that the biaxial testing method is applicable to AA6082 for formability evaluation under hot stamping conditions. In addition, the limit major strains vary with the strain state, but exhibit a minor dependency on the temperature in the range investigated.
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KADEN, Christoph. "Microstructure and hot deformation behavior of twin roll cast ZAX210 magnesium wire". W Metal Forming 2024, 2–10. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-1.
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Abstract. The hot deformation behavior of a Mg-2Zn-1Al-0.3Ca (ZAX210) wire, manufactured by twin roll casting was investigated by hot compression tests conducted at different temperatures (250 – 400°C) and strain rates (0.01 - 10 s-1). The analyses of the microstructure and the texture are determined by an optical microscope and scanning electron microscope. A processing map is developed to identify optimal process parameters. The twin roll cast state shows the presence of {101 ̅2} extension twins, {101 ̅1} compression twins, double twins, and a weak prismatic texture. Furthermore, regions with small recrystallized grains as well as a small segregation line extend across the center of the wire. The heat treatment at 420°C for 2 h results in a grain structure, consisting of equiaxed grains with an average grain size of approximately 32 µm in the center and 17 µm at the edges of the wire. The heat treatment further reduces the segregation and weakens the texture by spreading the basal plane along the transverse direction. In contrast to the initial state, only {101 ̅2} extension twins can be observed. The experimental results of the compression tests show that the flow stress increases with higher strain rates and decreasing temperatures. The course of the flow curves indicate that dynamic recrystallization occurs during hot deformation. The activation energy for plastic deformation of the twin roll cast and heat-treated wire is calculated to 150 kJ/mol. The process map identifies optimal process parameters, while deviations from these parameters result in crack formation, primarily at grain boundaries.
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LI, Shuo. "Eccentricity-resistant process design and finite element analysis of deep hole cylindrical parts". W Metal Forming 2024, 589–96. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-63.
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Abstract: In this paper, finite element analysis software was used to simulate and compare the deep-hole cylindrical parts formed by single process hot extrusion and double-process hot extrusion under the condition of uneven initial circumferential temperature of billet. The results show that the deformation resistance of the material is affected by the uneven temperature, and the strength of the single process hot extrusion parts is weakened because of the long punch length, which is easy to cause the eccentricity problem of the deep-hole cylindrical parts, and the wall thickness difference of the deep-hole cylindrical parts reaches 1.23 mm. The double-process hot extrusion can greatly reduce the influence of eccentricity on the deep hole cylindrical parts, make the wall thickness distribution more uniform, and the wall thickness difference is 0.38 mm. At the same time, the double-process hot extrusion reduces the forming force by 900 T and improves the feasibility of the process.
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CAI, Zhongman. "Development of unified constitutive model for hot deformation behavior of TC4 with and without diffusion bonding". W Metal Forming 2024, 548–57. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-59.
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Abstract. The hot deformation behavior of TC4 with and without diffusion bonding (DB) is studied. Firstly, the hot tensile testes of TC4 specimens with and without DB were carried out at temperature of 750℃ and strain rate of 0.1 ~ 0.0001 s-1. It was found that the peak stress and fracture strain of DB specimens are lower than those of base metal (BM) specimens. The quasi-cleavage fracture appeared in the DB specimens at 750℃, and the mechanism could be explained as straight grain boundary formed by incomplete recrystallization and insufficient grain boundary migration energy and the joints weak left over from the DB process causing rapid voids nucleation at the DB interface. The shorter distance of voids coalescence within the interface leads to quasi-cleavage fracture. In addition, a unified constitutive model based on internal variables was developed by introducing the weld-dependent fracture coefficients and damage tolerance coefficient. The model can accurately predict the hot deformation behavior of TC4 with and without diffusion bonding, describing the influence behavior of DB area on hot deformation, as well as the evolutions of internal variables, including dislocation density, reserve fraction, dynamic recrystallization (DRX) fraction and damage. It provides a theoretical basis for further accurate simulation of the hot forming of titanium alloy with diffusion bonding.
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CHANG, Shupeng. "Achievement of martensite strengthening in titanium alloy thin-walled components via non-equilibrium hot stamping". W Metal Forming 2024, 744–51. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-79.
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Abstract. The hot stamping using cold die technology demonstrates great advantages in improving the forming efficiency of titanium alloy thin-walled components. Martensite has been widely employed to strengthen steels, yet few applications were reported in titanium alloys. The main reason is that the martensite microstructure embrittles titanium alloys easily. In this paper, the non-equilibrium hot stamping technology is proposed for titanium alloys to solve the strength-ductility trade-off caused by martensite microstructure. Rapid heating is used to control phase transformation and grain growth during the short-time heating and obtain non-equilibrium microstructure. Non-equilibrium hot stamping experiments of the Ti-6Al-4V alloy were carried out to validate the feasibility. Results show that the rapid heating in the single β-phase region could avoid overgrowth of β grains and lead to the formation of fully fine martensite after water quenching. An Ω-shaped component with fully martensite microstructure were successfully formed by non-equilibrium hot stamping technology. The formed component has a maximum tensile strength of 1153.9 MPa, with a total elongation of 8.0% at room temperature, and the tensile strength is 13.0% higher than that of the as-received sheet.
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CHEN, Jiafeng. "Study of die punching process for hot stamped high strength steel and its performance evaluation". W Metal Forming 2024, 752–57. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-80.
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Abstract. Using the hot stamping process to produce ultra-high strength steel parts has been regarded as a good option for lightweight of automotive parts. Hot stamped workpieces usually require post-stamping processes like hole machining before they can be utilized. Considering industrial production, die punching process is more attractive than other hole machining methods such as laser cutting due to its high efficiency and low cost. In this study, the die punching process for hot stamped steel Usibor 1500P was investigated, and the performance of the punched parts was also explored. Firstly, the influence of process parameters including punching velocity, die clearance, punch corner radius, punch diameter, etc. was studied through a specifically designed trimming tool. Corner radius at the punch edge significantly improves the sheared edge quality, and tapered punch and conical punch evidently reduce and raise blanking force respectively. Secondly, several finite element fracture models for die punching process of Usibor 1500P were constructed and validated, where the Oyane and MMC damage models are considered suitable for punching simulation. Thirdly, the service performances of hot stamped ultra-high strength steel after die punching were evaluated through some typical experiments, including tensile tests, bending tests, and hydrogen embrittlement tests.
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BUCCONI, Marco. "Environmental impact assessment and comparative analysis of hot stamping and cold stamping processes: A cradle-to-gate lifecycle assessment study". W Metal Forming 2024, 261–70. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903254-29.
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Abstract. This manuscript presents the results of a cradle-to-gate lifecycle assessment (LCA) conducted on a component manufactured through two distinct process routes: Hot stamping of AA6082-T6 and cold stamping of AA5251-H22. The primary objective of this study is to provide a detailed understanding of the environmental impact associated with these processes and to conduct a comparative analysis of their environmental profiles. A comprehensive process map was developed for each manufacturing route, delineating all inputs and outputs at each step. Forming trials were executed during the LCA, capturing equipment energy consumption. When immediate data was unavailable from trials, the LCA model was supplemented with information from the Ecoinvent 3.6 database. The analysis demonstrates that the adoption of advanced near-net-shape manufacturing, specifically hot stamping, can significantly diminish the environmental impact compared to traditional cold stamping processes. Despite the additional energy requirements for heating in hot stamping, the overall environmental savings, supported by uncertainty analysis, are considerable. In the case of the examined demonstrator part, hot stamping showcased a noteworthy 35% reduction in CO2 equivalent emissions, equivalent to 6 kg CO2e per part. This reduction is primarily attributed to two key factors: the decreased material thickness achievable in hot stamping while preserving equivalent mechanical characteristics in the final part and the recycling of any material waste after forming. The results underscore the environmental advantages of embracing advanced manufacturing techniques, contributing valuable insights for environmentally conscious decision-making in the manufacturing industry.
Raporty organizacyjne na temat "Hot metal forming"
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Desbarats, A. J., i J. B. Percival. Hydrogeochemistry of mine tailings from a carbonatite-hosted Nb-REE deposit, Oka, Quebec, Canada. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331256.
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Environmental impacts associated with the mining of carbonatite deposits are an emerging concern due to the demand for critical metals. This study investigates the chemistry of tailings seepage at the former Saint Lawrence Columbium mine near Oka, Québec, Canada, which produced pyrochlore concentrate and ferroniobium from a carbonatite-hosted Nb-REE deposit. Its objectives are to characterize the mineralogy of the tailings and their pore water and effluent chemistries. Geochemical mass balance modeling, constrained by aqueous speciation modeling and mineralogy, is then used to identify reactions controlling the chemical evolution of pore water along its flow path through the tailings impoundment. The tailings are composed mainly of REE-enriched calcite (82 wt. %), biotite (12 wt. %) and fluorapatite (4 wt. %). Minor minerals include chlorite, pyrite, sphalerite, molybdenite and unrecovered pyrochlore. Secondary minerals include gypsum, barite and strontianite. Within the unsaturated zone, pore water chemistry is controlled by sulfide oxidation and calcite dissolution with acid neutralization. With increasing depth below the water table, pore water composition reflects gypsum dissolution followed by sulfate reduction and FeS precipitation driven by the oxidation of organic carbon in the tailings. Concomitantly, incongruent dissolution of biotite and chlorite releases K, Mg, Fe, Mn, Ba and F, forming kaolinite and Ca-smectite. Cation exchange reactions further remove Ca from solution, increasing concentrations of Na and K. Fluoride concentrations reach 23 mg/L and 8 mg/L in tailings pore water and effluent, respectively. At a pH of 8.3, Mo is highly mobile and reaches an average concentration of 83 µg/L in tailings effluent. Although U also forms mobile complexes, concentrations do not exceed 16 µg/L due to the low solubility of its pyrochlore host. Adsorption and the low solubility of pyrochlore limit concentrations of Nb to less than 49 µg/L. Cerium, from calcite dissolution, is strongly adsorbed although it reaches concentrations (unfiltered) in excess of 1 mg/L and 100 µg/L in pore water and effluent, respectively. Mine tailings from carbonatite deposits are enriched in a variety of incompatible elements with mineral hosts of varying reactivity. Some of these elements, such as F and Mo, may represent contaminants of concern because of their mobility in alkaline tailings waters.