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is carried out on a LASCO HOU-160 forging hammer with a power of 16 kJ, in two operations, on the blocking impression and then on the finishing impression. In order to assess the influence of the nitriding process on the durability of tools, operational tests are carried out for three sets of tools after thermochemical treatment under real industrial conditions and then confronted with the results for standard tools (without a nitrided layer). The comprehensive studies carried out, including macroscopic analyses combined with scanning, numerical modeling, and microstructural tests for both standard tools and after nitriding, show a decrease in the durability of forging tools as a result of the use of nitriding in relation to the previous technology. It should also be considered that the process was carried out on hammers, for very thin forgings. Then, there are very high dynamic loads, which can lead to cracking of hard nitriding layers.
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.
production of ceramic roof tiles. The tests included the determination of resistance to abrasive wear in ball-on-disc tests, hardness measurements, and microstructure analysis, including the assessment of changes occurring in the subsurface area, as well as impact tests (at a working temperature for the tools of 50°C). The comprehensive test results showed that the best effects of increasing the resistance to abrasive wear can be obtained through a heat treatment that consists of hardening at 1020°C and then tempering at 200°C for about 2 hours. The next stage of research will be to compare the results obtained with another popular material for tools for the production of roof tiles - Hardox steel, which is characterized by high resistance to abrasive wear.
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the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108° and 113°) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.
thickness, chemical composition and properties. When pulled through the drawing die the zinc coating heats up (as a result of friction between the material and the tool) and its dynamic plastic deformation. It resulted in the fracture and partial crushing of the hard-intermetallic phases. It has been proven that as the wire passes through successive drawing dies, the coating is thinned and diffusion as well as phase remodelling of individual structural components occurs; in the place of phase ζ, the intermetallic phase δ1 develops, increasing its share in the diffusion layer. The crystals of intermetallic phases located on the border of the diffusion and outer layers break up and remain dispersed in the zinc. An analysis of the microhardness of the coating has proven that the level of the increase in the microhardness of the zinc coating is contingent on percentage of iron in particular layers of coating.
size and the forging material recrystallization was elaborated with the use of the calculation packet Qform 7. In the first place, an in-depth analysis of the currently realized forging technology was made, with a special consideration of the temperature changes in the tools as well as in the formed forging. Next, numerical modelling of the process was carried out, as a result of which the following were obtained: correct filling of the tool impressions by the deformed material, the temperature distributions for the forging and the tools, the plastic deformation distributions (considering the thermally activated phenomena), the changes in the grain size and the forging force courses. The results obtained from FEM enable a thorough analysis of the forging process, including: the effect of the deformation time and temperature on the grain size in the forging material, which was confirmed by the microstructure examination results.
performed to increase the production efficiency without lowering the quality and mechanical parameters of the produced forgings and with preserved durability of the forging instrumentation. The conducted investigations included numerous aspects of the whole process line, with a special consideration of the adjustment of the currently realized technology to the working conditions of the robots in reference to the ejector system ensuring proper collection and relocation of the forgings by the manipulator grippers in the consecutive operations. The conduct also included the selection and localization of the robots and the grippers solutions, as well as the changes in the tool construction aiming at adjusting it to the gripper pins as well as collecting the hot charge material from the heater. Implementing robotization into one of the most difficult production processes aimed at replacing the role of a human by transferring the competences from the operator of the die forging process onto a supervising person, where all the activities are realized automatically, thus eliminating the effect of the human factor on the quality of the manufactured product. Additionally, the robotization of the forging process brought a lot of tangible benefits, such as stability and repeatability of the process (reduction of reject rate), as well as increased efficiency and quality of the forgings.
process and then improve the currently implemented forging technology by using finite element (FE) simulation. QuantorForm (the developer of the QForm program) has developed a thermomechanical numerical model for the production of forked forging. The software Computer-Aided Three-Dimensional Interactive Application (CATIA) was used to develop and build Computer-Aided Design (CAD) models of forging tools. As a result of the numerical simulations, the plastic deformations and temperature distributions for the forgings and tools were obtained, and the force courses during the forging process were analyzed. The obtained results enabled a thorough analysis of the forging process, including identification of potential forging defects (laps) as well as those tool areas that are the most loaded and exposed to damage. On this basis, changes were implemented in the production process, which allowed for the improvement of the currently implemented technology and obtaining the corrected forgings.
800 forgings. To perform an in-depth analysis of the effect of the nitrided layer thickness (0.1 mm and 0.2 mm) and the tool material (W360 and QRO90) on the possibilities of increasing the die durability, complex studies were carried out, which included: a macroscopic analysis combined with 3D scanning, microstructural examinations using a scanning microscope and a metallographic microscope, as well as hardness measurements. A minimum of three tools were tested for different variants, and for each of them, one representative die was selected for detailed examinations. The research showed the presence of abrasive wear, thermo-mechanical fatigue and traces of adhesive wear as well as plastic deformation on the surface of the working impressions. Also observed was the effect of the extruded material sticking to the tools (high friction and the presence of intermetallic phases in the extruded material) and the forging being blocked in the smallest section of the die, which is a critical factor causing a production shutdown and the necessity of tool replacement. The highest mean durability equalling 2600 forgings was obtained for the dies with a lower carbon content and a higher content of vanadium and the nitrided layer thickness at the level of 0.2 mm. The lowest mean durability (after one forging item) was recorded for the dies made of steel with a higher carbon content and a higher chromium content, forming less stable compound carbides and the thickness layer at the level of 0.1 mm.
wszystkim na określenie parametrów/ wielkości, które trudno wyznaczyć bezpośrednio w procesie lub w sposób doświadczalny, a dla których wyznaczone i następnie wprowadzone w modelowaniu ich zmiany mogą wpłynąć na poprawę aktualnie realizowanej technologii.
opracowano przy użyciu oprogramowania Qform 7. W wyniku przeprowadzonego modelowania uzyskano, m.in.: rozkłady temperatur dla odkuwki i narzędzi oraz odkształceń plastycznych (uwzględniających zjawiska aktywowane cieplnie), zmiany wielkości ziarna oraz przebiegów sił kucia. Otrzymane wyniki pozwalają na pełną analizę procesu kucia, w tym: wpływu czasu i temperatury odkształcania na wielkość ziarna w materiale odkuwki.
developed using Qform 7 software. As a result of the modeling, among others: temperature distributions for forging and tools as well as plastic deformations (taking into account thermally activated phenomena), grain size changes and waveforms forging forces have been determined. The obtained results allow for a full analysis of the forging process, including: the influence of time and temperature of deformation on the grain size in the forging material.
długiego trzonka, a następnie kucia wykańczającego głowy zaworu. Głównym problemem w tym procesie jest stosunkowo niska trwałość narzędzi; w pierwszej operacji wyciskania obserwowane jest przedwczesne zużycie matrycy, a w drugiej operacji niska trwałość stempla, co związane jest z intensywnym zużyciem ściernym oraz adhezją materiału odkuwki do narzędzi. Modelowanie numeryczne przeprowadzono przy użyciu pakietu obliczeniowego Forge 2.0, w celu analizy wpływu zmian warunków temperaturowych oraz tarcia. Szczegółowej analizie poddano drugą operację kształtowania – kucie na gorąco głowy zaworu, gdyż w przemysłowym procesie, ze względu na niewystarczającą kontrolę kluczowych parametrów technologicznych, mogą wystąpić niewielkie zmiany warunków tribologicznych, co wpływa na poprawność całego procesu. Przeprowadzona wielowariantowa analiza procesu kucia z wykorzystaniem modelowania numerycznego do-starczyła wielu cennych informacji dotyczących zmian kluczowych parametrów trudnych do uzyskania podczas analizy procesu przemysłowego oraz ich wzajemnego wpływu na siebie, takich jak: rozkłady pól temperatury, nacisków oraz parametrów określających zużycie, a także przebiegów sił kucia. Na tej podstawie możliwe jest wprowadzenie bez większych obaw istotnych zmian w procesie przemysłowym, w celu uzyskania jego stabilności i powtarzalności oraz zwiększeniu trwałości oprzyrządowania kuźniczego.
followed by finishing forging of the valve head. The main problem in this process is a relatively low tool durability; in the first extrusion operation, we observe premature wear of the die, whereas in the second operation, a low durability of the punch can be noticed, which is connected with the intense abrasive wear as well as adhesion of the material of the forging to the tools. The numerical modelling was carried out with the use of the Forge 2.0 calculation packet in order to analyze the effect of the temperature conditions and friction. A detailed analysis was performed on the second forming operation – hot forging of a head valve, as, in the industrial process, due to insufficient control of the key technological parameters, slight changes of the tribological conditions might occur, which affect the properness of the whole process. The multi-variant analysis of the forging process with the use of numerical modeling provided a lot of valuable information regarding changes in key parameters difficult to obtain during the analysis of the industrial process and their mutual influence on each other, such as: distribution of tem-perature fields, pressures and parameters determining wear, as well as forging force courses. On this basis, it is possible to introduce without major worry significant changes in the in-dustrial process in order to obtain its stability and repeatability, and increase the durability of forging equipment.
wytwarzania odkuwki. Termomechaniczny model kucia odkuwki z odkształcalnymi narzędziami opracowano przy użyciu oprogramowania Forge NX 2.0. Do zbudowania modeli narzędzi kuźniczych wykorzystano program Catia. W wyniku przeprowadzonego modelowania uzyskano, m.in.: rozkłady temperatur dla odkuwki i narzędzi oraz odkształceń plastycznych (uwzględniających zjawiska aktywowane cieplnie), a także zmiany wielkości ziarna oraz przebiegi sił kucia. Otrzymane wyniki pozwalają na pełną analizę procesu kucia, w tym: wpływu czasu i temperatury odkształcania na wielkość ziarna w materiale odkuwki, co w przyszłości może pozwolić na wykorzystanie ciepła kucia do planowanej obróbki cieplnej i uzyskania określonej mikrostruktury.
thermomechanical model of forging process with deformable tools was developed using the Forge NX 2.0 software. Catia program was used to build models of forging tools. As a result of the modeling obtained, inter alia: temperature distributions and plastic deformations for the forging (taking into account thermally activated phenomena), as well as grain size changes and forging forces. The obtained results allow for a full analysis of the forging process, including: identification of potential forging defects (overlaps) and the influence of time and temperature of deformation on the grain size in the forging material, which in the future may allow using the forging heat for the planned heat treatment and obtaining a specific microstructure.
their operation on the dimensional accuracy of the forgings. The performed analysis included the 4 variants which are that have the most common place in the industrial process that is, for a combination of new and partly worn out die inserts (used during hot forging) and new and partly used cutting tools used for cold trimming. The first stage involved modelling of a hot die forging process. Next, the obtained results were implemented into second modelling stage, which involved a simulation of a cold trimming process of a flash, with the use of the normalized Cockcroft-Latham fracture criterion, with the consideration of eliminating the removed elements, for which the cracking value has been exceeded. The obtained results was verified by means of a case study under industrial conditions for the least favourable operating conditions of both types of tools and their impact on the dimension-shape precision of the forgings. These results allowed for a more complete analysis of the trimming process for a variety of operating conditions and the confirmation of the correctness of carried out numerical modelling, and thus the possibility of its use in combination with scanning technique to computer-aided manufacturing processes. The proposed solution allows the selection of optimum conditions for implementation of the processes of forging and trimming because of their use to provide the required net shape forgings.
wzajemnego wpływu ich eksploatacji na dokładność wymiarową odkuwek. Przeprowadzona analiza obejmowała 4 warianty najczęściej występujące w procesie przemysłowym, czyli dla kombinacji nowych i częściowo wyeksploatowanych wkładek matrycowych (stosowanych podczas kucia na gorąco) oraz nowych i częściowo zużytych narzędzi okrojczych wykorzystywanych do okrawania na zimno. W pierwszym etapie zamodelowano proces kucia matrycowego na gorąco. Następnie uzyskane wyniki zaimplementowano do drugiego etapu modelowania, w którym zasymulowano proces okrawania na zimno wypływki przy zastosowaniu znormalizowanego kryterium pękania Cockcrofta-Lathama z uwzględnieniem eliminacji elementów, dla których została przekroczona wartość pękania. Uzyskane wyniki zostały zweryfikowane za pomocą studium przypadku w warunkach przemysłowych dla najmniej korzystnych warunków eksploatacji obu rodzajów narzędzi oraz ich wpływu na dokładność wymiarowo-kształtową odkuwki. Uzyskane wyniki pozwoliły na pełniejszą analizę procesu okrawania dla różnych warunków eksploatacyjnych oraz potwierdzenie poprawności przeprowadzonego modelowania numerycznego, a tym samym możliwości jego wykorzystania do komputerowego wspomagania procesów wytwarzania. Zaproponowane rozwiązanie pozwala na wybór optymalnych warunków realizacji procesów kucia i okrawania ze względu na ich eksploatację w celu zapewnienia wymaganej dokładności wymiarowo-kształtowej odkuwek.
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