This rapport discusses a Bachelor's thesis conducted at Gestamp Hardtech in Luleå, a company that invented the press hardening technique and still today is one of the leading companies utilising this type of process. A method used in the manufacture of ultra-high strength steel components. The main use of press hardening is when forming sheet metal for the automotive industry, because of the very high resistance to deformation and in turn low weight parts made from this process can offer. The number of of body parts for cars made with this process is high but yet rising as the method is being advanced, the technique is highly advanced and requires both knowledge and process control to manage. The creation of soft zones is a big part of hot stamping. A soft zone is a part of a material with lower strength and hardness, which is achieved by lowering the cooling rate at a specific area of the piece, resulting in a product that is both hardened and soften. For this project, only the soft zones were focused on and not the relation between hardened zones, this was for the interest in having the same mechanical properties over the whole metal sheet used. The questions that this project will try to answer is the possibilities of introducing new materials that can be used in hot stamping with combination of building in soft zones in them. It will also deep dive in to each of the materials materials mechanical properties achieved when process and give data that in the future can be used to build other projects on. While the project is built on the standard used today on softer materials process parameters, a recipe more based on production experience and default setting in the manufacturing line, it will answer if these settings might still hold true for these materials and if not what kind of parameters are more preferred. The reason why this project is of interest is because the automotive industry today has a great desire in lowering weight of the vehicle without reducing the quality. This project is a big step in the direction of finding a material that can provide the same mechanical properties while reducing the volume of the material. Soft zone plane sheets were made by direct hot stamping in the research line in Luleå. The main parameters changed in the different trials were: material, die temperature and cooling time.

In recent years, there has been an increase in the use of press hardened steel (PHS) in the body-in-white of automobiles, namely in parts such as side impact beams, roof rails, engine firewalls, and the floor area. As these parts are expected to possess corrosion resistance, Al-Si coatings are utilized on them. The implementation of Zn coatings is limited, despite possessing improved corrosion resistance attributed to cathodic corrosion protection, due to the detrimental effects of liquid metal embrittlement (LME) and microcracking. LME can be mitigated if stamping occurs at a temperature lower than the Fe-Zn peritectic temperature of 782 °C, as this ensures that the conditions of LME are not met and the cathodically-protective Γ-Fe3Zn10 phase is formed. The objective of this work was to determine a process window for stamping at lower temperatures for a GA80-coated prototype steel (steel K) with the composition of 0.19C-1.92Mn-0.20Si-0.003B-0.03Ti (wt.%). The target mechanical properties in this process window were UTS ≥ 1400 MPa, and YS ≥ 1000 MPa. To achieve robust cathodic corrosion protection, more than 15 vol% of Γ-Fe3Zn10 in the coating was desired. Furthermore, it was aimed to determine the robustness of this process and the industrial feasibility of it through pilot-scale trials for the GA80-coated prototype steel. To this end, a bare prototype steel (steel I) with the composition of 0.20C-1.96Mn-0.25Si-0.003B-0.01Ti was compared to GA-coated steel K. It was found that stamping a direct hot press forming (DHPF) temperature of 650 °C produced similar mechanical properties such as tensile strengths and ductilities. Microstructural analysis of laboratory-scale DHPF for steel K showed that both the coating and the substrate microstructures were not a strong function of the DHPF temperatures of 550 – 700 °C. The substrate predominantly consisted of martensite with small amounts of ferrite and the coating consisted of α-Fe(Zn) and ≥ 15 vol.% Γ-Fe3Zn10. Based on the fraction of Γ-Fe3Zn10 and the coating thickness, robust cathodic corrosion protection is expected from GA80-coated steel K. Furthermore, no evidence of LME or severe microcracking was observed in the microstructure for DHPF temperatures of 550–700 °C for steel K and ductile fracture was observed in tensile coupons. Tensile testing for laboratory-scale DHPF for steel K showed that the mechanical properties such as YS, UE and PUE were not significantly affected by DHPF temperatures of 550-700 °C. Moreover, the targets of UTS ≥ 1400 MPa, and YS ≥ 1000 MPa were met for all DHPF temperatures of 550 – 700 °C. Through pilot-scale tensile testing of steel K, it was determined that the targets for tensile strengths (UTS and YS), were achieved across various conditions involving austenitization at 890 °C for 60 – 240 s and DHPF temperatures ranging from 550 – 700 °C. These findings strongly suggest that industrial feasibility is attainable for DHPF of GA-coated steel K at lower temperatures, enabling the attainment of desirable mechanical properties and robust corrosion protection. Thus, it can be concluded that the process window yielding desirable properties for steel K was determined to be austenitization at 890 °C for 60 – 240 s and DHPF temperatures between 550 – 700 °C. / Thesis / Master of Applied Science (MASc) / The forming process of the steels used in the automotive industry is not suitable for zinc coatings because it requires pressing at high temperatures to ensure obtaining strong steels. Thus, zinc coatings cannot be utilized despite the desirable cathodic corrosion protection properties they can provide. This study aimed to determine a suitable process window for a zinc-coated prototype steel that would have both high strength and desirable corrosion protection. The zinc-coated prototype steel was pressed at lower temperatures. It was observed that the target mechanical properties were met for all the temperatures tested. Moreover, robust cathodic corrosion protection is expected for all the temperatures. Furthermore, pilot-scale tests yielded comparable results to those obtained in the laboratory, indicating that this process can be successfully applied in the industry as it possesses a sufficiently large process window.

No description available.

No description available.

No description available.

Never before has the car industry been as challenging, interesting, and demanding as it is today. New and advanced techniques are being continuously introduced, which has led to increasing competition in an almost ever-expanding car market. As the pace and complexity heightens in the car market, manufacturing processes must advance at an equal speed. An important manufacturing process within the automotive industry, and the focus of this thesis, is sheet metal forming (SMF). Sheet metal forming is used to create door panels, structural beams, and trunk lids, among other parts, by forming sheets of metal in press lines with stamping dies. The SMF process has been simulated for the past couple of decades with finite element (FE) simulations, whereby one can predict factors such as shape, strains, thickness, springback, risk of failure, and wrinkles. A factor that most SMF simulations do not currently include is the die and press elasticity. This factor is handled manually during the die tryout phase, which is often long and expensive. The importance of accurately representing press and die elasticity in SMF simulations is the focus of this research project. The research objective is to achieve virtual tryout and improved production support through SMF simulations that consider elastic die and press deformations. Loading a die with production forces and including the deformations in SMF simulations achieves a reliable result. It is impossible to achieve accurate simulation results without including the die deformations. This thesis also describes numerical methods for optimizing and compensating tool surfaces against press and die deformations. In order for these compensations to be valid, it is imperative to accurately represent dies and presses. A method of measuring and inverse modeling the elasticity of a press table has been developed and is based on digital image correlation (DIC) measurements and structural optimization with FE software. Optimization, structural analysis, and SMF simulations together with experimental measurements have immense potential to improve simulation results and significantly reduce the lead time of stamping dies. Last but not least, improved production support and die design are other areas that can benefit from these tools. / Aldrig tidigare har bilindustrin varit så utmanande, intressant och spännande som idag. Ny och avancerad teknik introduceras i en allt snabbare takt vilket leder till ständigt ökande konkurrens på en, nästan ständigt, ökande bilmarknad. Den ständigt ökande komplexiteten ställer även krav på tillverkningsprocesserna. En viktig process, som denna licentiatuppsats fokuserar på, är pressning av plåt. Tillverkningstekniken används för att forma plåtar till dörrpaneler, strukturbalkar, motorhuvar, etc. Plåtar formas med hjälp av pressverktyg monterade i plåtformningspressar. Plåtformningsprocessen simuleras sedan ett par decennium tillbaka med Finita Element (FE) simuleringar. Man kan på så sätt prediktera form, töjningar, tjocklek, återfjädring, rynkor, risk för försträckning och sprickor m.m. En faktor som för tillfället inte inkluderas i näst intill alla plåtformningssimuleringar är elastiska press- och verktygsdeformationer. Detta hanteras istället manuellt under, den oftast långa och dyra, inprovningsfasen. Detta projekt har visat på vikten av att representera press och verktygsdeformationer i plåtformningssimuleringar. Detta demonstreras genom en analys av ett verkligt pressverktyg som belastas med produktionskrafter. Det är inte möjligt att uppnå bra simuleringsresultat utan att inkludera verktygsdeformationer i simuleringsmodellen. Uppsatsen beskriver även numeriska metoder för att optimera och kompensera verktygsytor mot press och verktygsdeformationer. För att dessa kompenseringar ska stämma är det viktigt att man representerar både verktyg och press på ett korrekt sätt. Förslag på en metod för att mäta och inversmodellera pressdeformationer har utvecklats, metoden är baserad på mätningar med DIC-systemet ARAMIS och optimering i FE-mjukvaror. Optimering, strukturanalys, och plåtformningsanalys tillsammans med experimentella mätningar har en stor potential att förbättra plåtformningssimuleringar samt reducera ledtiden för pressverktyg. Sist men inte minst, andra positiva effekter är en enklare och smidigare konstruktionsprocess och förbättrad produktionssupport.

Diploma thesis introduces the design of a functional part of a wine opener, focusing on simplicity and effectivity of the manufacturing process with the use of progressive stamping tool. The part will be made by technology of progressive cutting and bending. For the production of the specified part stainless steel coil marked as 17 241.4 will be used This material is suitable for the use in commercial gastronomy thanks to its qualities. Also in this thesis there are technical calculations, suggestios for of optimal tools, economic calculations, and technical-economic evaluation of the production of the specified part.

Объектом исследования является технологический процесс штамповки детали болт по ГОСТ 7798-70 на предприятии ООО «Арморика». Выполнено исследование влияния температуры нагрева заготовок на технологические факторы штамповки поковок фланца на пресс КГШП, а именно усилие штамповки, анализ напряженно – деформированного состояния штамповки поковки фланца, оценка проработки структуры металла. Выполнена разработка технологического процесса штамповки болта, расчет усилия пресса, компьютерное моделирование процесса горячей объемной штамповки болта с заданной в технологическом процессе температурой, технологичного, анализ влияния нагрева заготовок на технологические факторы, литературный обзор. / The object of the study is the technological process of stamping the bolt part according to GOST 7798-70 at the Armorica LLC enterprise. The study of the effect of the heating temperature of the workpieces on the technological factors of stamping flange forgings on the KGSHP press, namely the punching force, analysis of the stress–strain state of stamping flange forgings, evaluation of the study of the metal structure. The development of the technological process of bolt stamping, calculation of the press force, computer modeling of the process of hot volumetric stamping of a bolt with a temperature set in the technological process, technological, analysis of the effect of heating workpieces on technological factors, a literary review.

Eine effiziente und effektive Technologieentwicklung und –optimierungen im Bereich der Umform- und Fertigungstechnik erfolgt heutzutage fast ausschließlich rechnergestützt auf Basis der Finiten Elemente Methode (FEM) oder der Finiten Differenzen Methode (FDM). Die aktuellen Umformsimulationssysteme sind in der Lage die notwendige Energie der Anlagen, den prozessbedingten Stofffluss des Umformgutes inkl. der resultierenden Temperaturen und die Spannungen des Halbzeuges bzw. Bauteiles als auch der Werkzeuge vorauszuberechnen. Allerdingssind bereits dafür die sehr sensitiven Materialdaten, wie z. B. temperatur- und umformgeschwindigkeitsabhängige Fließkurven, Wärmeleitfähigkeit usw., notwendig. Momentane Forschungsaktivitäten beschäftigen sich damit, den nächsten Schritt der FE-Simulation zu bewältigen, in dem die Gefügeentwicklung und die daraus resultierenden mechanischen Eigenschaften (Zugfestigkeit, Bruchdehnung etc.) numerisch ermittelt werden können. Auch dafür müssen sehr aufwendige und materialspezifische Materialdaten generiert und modelliert und abschließend in Simulationssysteme über Schnittstellen implementiert werden. Die Vorhersage zu Verschleiß und Versagen von Werkzeugen wird in Zukunft immer mehr in das Interesse von Anwendern von FE-Software rücken, um die kompletten Einflussgrößen der Prozesse abzubilden. Dieser Beitrag soll am Beispiel einer aushärtbaren Aluminiumlegierung (EN AW 6.xxx) verdeutlichen, wie unterschiedlich das Materialverhalten in Abhängigkeit des Ausgangszustandes (stranggepresst, stranggegossen) und der Erwärmungsmodi (konvektiv, induktiv) sein kann und wie sich diese Variationen für ein und denselben Werkstoff auf die Berechnungsgenauigkeit ausgewählter Warmmassivumformprozesse (Reckwalzen, Gesenkschmieden) auswirkt.

Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples meet the 2015 target of the U.S. Department of Energy, surface coating is required. 5- ZrN and CrN coated BPPs exhibited higher corrosion resistance meeting DOE target while TiN coated samples had the lowest corrosion resistance. Higher coating thicknesses improved the corrosion resistance of the BPPs. 6- Process sequence between coating and manufacturing is not significant for hydroforming case (ZrN and CrN) and stamping case (CrN) in terms of the corrosion resistance. In other words, coating the BPP`s substrate material before manufacturing process does not always decrease the corrosion resistance of the BPPs.