ABSTRACT The objective of the present work is a basic study of production, modelling and validati... more ABSTRACT The objective of the present work is a basic study of production, modelling and validation of sheet composites of AA6xxx-automotive alloy and IF-steel. In this context the influence of surface preparation, pre-heating temperature of aluminium and steel plate, and thickness reduction on the bond strength of the composites as well as on the formation of intermetallic interface layers is analysed by shear tests and metallographic evaluations of the interface.
In order to understand the tribological processes and interactions in the tool-workpieceinterface... more In order to understand the tribological processes and interactions in the tool-workpieceinterface systematically, basic experiments that allow an independent variation of influencing parameters are necessary. The ring-on-disc test is a popular model experiment that is often used in tribological analyses at low normal contact pressures.
ABSTRACT The objective of the present work is a basic study of production, modelling and validati... more ABSTRACT The objective of the present work is a basic study of production, modelling and validation of sheet composites of AA6xxx-automotive alloy and IF-steel. In this context the influence of surface preparation, pre-heating temperature of aluminium and steel plate, and thickness reduction on the bond strength of the composites as well as on the formation of intermetallic interface layers is analysed by shear tests and metallographic evaluations of the interface.
... Bei Spannungen über 220 kV werden Bündelleiter verwendet, um dem Korona-Effekt zu entgegnen. ... more ... Bei Spannungen über 220 kV werden Bündelleiter verwendet, um dem Korona-Effekt zu entgegnen. ... Supraleitende Kabel sind zurzeit im Netz noch in Erprobung. 6.3 Werkstoffe für Energiespeicherung (Batterien und Akkus) ...
ABSTRACT Es werden die fertigungstechnischen Herausforderungen im Hinblick auf Umweltschonung bei... more ABSTRACT Es werden die fertigungstechnischen Herausforderungen im Hinblick auf Umweltschonung bei verbesserter Crash-Sicherheit sowie aktuelle Lösungen für die umformtechnische Fertigung von leichten Automobilkarosserien im Überblick dargestellt. Ausgehend vom stofflichen Leichtbau durch Verwendung hochfester Stahlfeinbleche oder Leichtmetalllegierungen werden die umformtechnischen Schwierigkeiten aufgezeigt. Hauptaugenmerk wird aber auf jene Fertigungstechnologien gelegt, die eine deutliche Senkung des Fahrzeuggewichts bei gleicher oder erhöhter Steifigkeit bzw. Festigkeit ermöglichen. Neben der Blechverarbeitung werden auch Ansätze für massivumgeformte Bauteile aufgezeigt. Manufacturing challenges with respect to environmental protection and improved crash performance as well as actual solutions for metal forming technologies are compared to produce light-weight vehicle bodies. Forming problems related to materials oriented concepts by using of high strength steel sheets or light metal alloys are shown. Main focus is, however, put on those forming technologies, which lead to significant reductions of car weight at almost the same or even better stiffness and strength behaviour. Beside sheet metal forming also concepts for massive formed components are presented.
This paper presents an experimental investigation of friction in hot forging of AA6082, which is ... more This paper presents an experimental investigation of friction in hot forging of AA6082, which is a standard forging alloy in automotive engineering, mechanical engineering and in naval architecture, by employing a modified ring-on-disc test. The experiments were performed with three different commercial graphite-based lubricants and at various loads, sliding velocities and specimen surface conditions. In addition, some tests were performed without lubrication.
The impact resistance and the fracture behaviour of sheet metals under ballistic impact condition... more The impact resistance and the fracture behaviour of sheet metals under ballistic impact conditions which depend significantly on some material characteristics like cold work hardening and ductility are important for the development of passive protection systems for passenger cars. To establish the impact of a projectile during penetration of a sheet metal, a FEM model was generated using the commercial FEM-code Abaqus/Explicit. The model was evaluated with real shooting experiments, where the impact behaviour of sheets made of different steels was tested at a shooting stand and the penetration was analysed metallographically. The evaluation showed that reasonable results from the simulation can only be achieved using a damage model concept and when the deformation of the bullet is considered in interaction with the deformation of the sheet metal. The variation of sheet thickness in the simulation shows good agreement with empirically developed formulations to predict the penetration power of a full metal jacket in steel sheets. With the evaluated model, parameter studies were performed to investigate the energy loss during the impact of a projectile into steel sheets with different hardening rates. The studies show that FEM simulation can give good basic knowledge about the impact behaviour of a projectile into steel sheets and can help to achieve higher protection in conjunction with weight reduction in protected passenger cars.
A model is presented that describes the development of texture during the production process of b... more A model is presented that describes the development of texture during the production process of bake-hardening steel recrystallized in a batch-annealing furnace. Proper conditions are analyzed to generate a pronounced ␥-fiber texture and a "pancake microstructure" that shows superior deep drawability. The ␥-fiber texture is assumed to be caused by the interaction between tertiary precipitating aluminum nitride particles and the recrystallization process during heating in the furnace. Deep drawability is presented in terms of the logarithmic ␥and ␣-fiber X-ray intensity ratio. The computer simulation of the coupled aluminum nitride precipitation and recrystallization kinetics is based on an iterative procedure. A comparison between simulation results and available experimental data proves the ability of the model to predict the final deep drawability, taking into account the initial aluminum and nitrogen contents, the time/temperature history during slab reheating, hot rolling and coiling, the degree of cold reduction, and the heating rate during batch annealing. assignment, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6376. V. PLETENEV, Postgraduate Student, and N. ZOLOTOREVSKY, Associate aluminum and nitrogen precipitation kinetics throughout the Professor, are with the
Forging Aluminium a b s t r a c t In this paper a number of aluminium forging lubricants were tes... more Forging Aluminium a b s t r a c t In this paper a number of aluminium forging lubricants were tested with respect to their lubricating effect and their applicability in the production of parts with long flow paths. The tests were conducted on a custom built testing machine that simulates the parameters of industrial production. The lubricants were assessed considering the change of the coefficient of friction during the test and the influence on tool and workpiece surface. From the presented analysis, the most appropriate lubricant for the investigated process was found.
Der Eindringwiderstand und das Bruchverhalten von Feinblechen bei Beschuss mit Projektilen sind f... more Der Eindringwiderstand und das Bruchverhalten von Feinblechen bei Beschuss mit Projektilen sind für die Entwicklung passiver Schutzmaßnahmen entscheidend. Die wichtigsten Einflüsse auf das ballistische Verhalten von Legierungen werden übersichtlich und insbesondere hinsichtlich des Gefügeeinflusses näher dargestellt. Das Beschussverhalten von Feinblechen eines weichen Stahles, eines höherfesten Vergütungsstahles, einer Aluminiumlegierung und eines metastabilen austenitischen Stahles wurde mit realen Beschusstests ermittelt und die Eindringwirkung metallografisch analysiert. Vergleichend dazu wurden Kragenziehversuche und numerische Simulationen zur Abschätzung des Ein dringverhaltens unterschiedlicher Werkstoffe durchgeführt.
Die Abbildung einer gewünschten Geometrie mittels Schmieden aus einem zylindrischen Vormaterial i... more Die Abbildung einer gewünschten Geometrie mittels Schmieden aus einem zylindrischen Vormaterial ist meist nicht in einem einzigen Schritt möglich. Für nahezu 90 % der Schmiedestücke müssen vor Erreichen der Endkontur eine oder mehrere Zwischenformen erzeugt werden, um eine Materialverteilung zu erhalten, die ein faltenfreies Bauteil mit optimaler Materialverteilung im letzten Schmiedeschritt gewährleistet. In der vorliegenden Arbeit wird am Beispiel des Schmiedens eines Pleuels eine einfache Vorgehensweise zur Vorformoptimierung beschrieben, die auch für die praktische Anwendung im täglichen Fertigungsbetrieb geeignet ist. Für den untersuchten Pleuel konnte so mit einem Arbeitsaufwand von wenigen Tagen eine Vorform gefunden werden, die im Vergleich zur bisherigen Gestaltung eine Materialeinsparung von 15 % und damit verbunden eine erhebliche Verringerung des Gesenkverschleißes an der Gratbahn ermöglicht.
Schrauben aus hochfesten Stählen und deren wirtschaftliche Fertigung unterliegen hohen Qualitätsa... more Schrauben aus hochfesten Stählen und deren wirtschaftliche Fertigung unterliegen hohen Qualitätsansprüchen und werden ständig weiter verbessert. Für hochfeste Schrauben werden üblicherweise MnB-und 1 %Cr-Stähle im vergüteten Zustand verwendet. Als kostengünstige Alternativen gelten thermomechanisch gewalzte Stähle, Dualphasenstähle und AFP-Stähle, die ohne zusätzliche Wärmebehandlung (Vergütung) hergestellt werden können. Ausgehend von der Beschreibung der metallurgischen und walzbedingten Einflüsse bei der Drahtherstellung und deren Auswirkungen auf die Umformbarkeit bei der Schraubenherstellung werden die alternativen Stahlgüten vergleichend dargestellt. Ergänzend dazu werden die verfahrenstechnischen Optimierungsmöglichkeiten bei der Schraubenfertigung betrachtet, wobei primär der Vorzug, die Eigenspannungsentwicklung und die Wärmebehandlung untersucht werden. Durch FE-Simulationen werden die Fertigungsschritte analysiert und mittels Schädigungsmodellen die Grenzen der Umformbarkeit aufgezeigt.
In der Vergangenheit wurden zahlreiche Fließbedingungen für das Verdichten von pulvermetallurgisc... more In der Vergangenheit wurden zahlreiche Fließbedingungen für das Verdichten von pulvermetallurgischen (PM) Werkstoffen entwickelt. Die meisten dieser Modelle basieren auf einem modifizierten "von Mises"-Ansatz. In der vorliegenden Arbeit werden unterschiedliche Fließbedingungen Shima & Oyane, Kuhn & Downey, Gurson, Gurson-Tvergaard und Doraivelu) in das Finite-Elemente (FE)-Programm Deform3D™ implementiert und untereinander verglichen. Die berechneten Werte werden mit Zylinderstauchversuchen mit unterschiedlicher Spannungstriaxialität verglichen. Durch die Überprüfung der FE-Rechnung anhand der Versuchsdaten wird gezeigt, dass unter den betrachteten Materialgesetzen das Modell nach Gurson-Tvergaard mit dichteabhängigen Parametern die Verdichtung von PM-Materialien am besten beschreibt. Implementation of Yield Functions in the FEM Software DEFORM 3D™ to Simulate the Densification of PM Materials. To determine the initiation of yielding and compaction of metal powder components, various different yield models have been proposed. Most of these models are based on a modified "von Mises" criterion. To obtain sufficient results from the Finite Element (FE) calculation of the compression process of PM parts, advanced material models (Shima & Oyane, Kuhn & Downey, Gurson, Gurson-Tvergaard and Doraivelu) have been implemented into the FE code Deform3D™. The calibration of these models is done by cylindrical compression tests with different stress triaxiality. The results of these tests show that the conformity between the calculated results based on the material model of Gurson-Tvergaard with density dependent parameters show a better fit than the results of the other investigated yield functions.
Lightweight thin walled structures are primarily dimensioned for stiffness of the whole construct... more Lightweight thin walled structures are primarily dimensioned for stiffness of the whole construction and less for material resistance. Usual design concepts for improving the stability behaviour of metal sheets introduce the configuration of fins, stiffeners, beads or embossing patterns. However these methods not only increase the moment of inertia but also the weight of the component. In this paper an alternative method for inserting residual stresses is presented and the influence of the static and dynamic behaviour is shown. Local laser spots and laser lines are introduced in order to achieve proper distributions of residual stresses. The effect on fundamental frequency and buckling resistance was investigated on steel sheets of 280 mm x 280 mm and a thickness of 0.75 mm in a special testing rig. Buckling load and mid-point displacement were measured by a LVDT-system. Correlations between residual stresses, fundamental frequency and buckling resistance could be found. During buckling tests the uniaxial applied load vs. mid-point deflection was measured. In order to illustrate the improvements of the buckling load, fundamental frequency and residual stresses have been analysed. In conclusion, the laser treatment and the insert of residual stress patterns by laser treatment, respectively, is a promising method to increase the static and dynamic behaviour for thin walled metal sheets.
Science and Technology of Welding and Joining, 2002
ABSTRACT The long range diffusion of rapidly diffusing elements in dissimilar welds, which occurs... more ABSTRACT The long range diffusion of rapidly diffusing elements in dissimilar welds, which occurs during heat treatment and in service exposure, initiates heavy microstructural changes on both sides of the weld. Various carbides and nitrides either dissolve or precipitate as a function of the distance from the fusion line. The type and amount of these particles can be predicted by a numerical method for solving problems of simultaneous precipitation and diffusion. Predicted precipitate distributions for a 2·25Cr/9Cr and a 2Cr/0·5CrMoV weld are verified using experimental data obtained with analytical and energy filtering transmission electron microscopy. The phase diagrams for the high chromium side and the low chromium side of the welds are evaluated and compared with the experimentally determined precipitate distribution.
ABSTRACT The objective of the present work is a basic study of production, modelling and validati... more ABSTRACT The objective of the present work is a basic study of production, modelling and validation of sheet composites of AA6xxx-automotive alloy and IF-steel. In this context the influence of surface preparation, pre-heating temperature of aluminium and steel plate, and thickness reduction on the bond strength of the composites as well as on the formation of intermetallic interface layers is analysed by shear tests and metallographic evaluations of the interface.
In order to understand the tribological processes and interactions in the tool-workpieceinterface... more In order to understand the tribological processes and interactions in the tool-workpieceinterface systematically, basic experiments that allow an independent variation of influencing parameters are necessary. The ring-on-disc test is a popular model experiment that is often used in tribological analyses at low normal contact pressures.
ABSTRACT The objective of the present work is a basic study of production, modelling and validati... more ABSTRACT The objective of the present work is a basic study of production, modelling and validation of sheet composites of AA6xxx-automotive alloy and IF-steel. In this context the influence of surface preparation, pre-heating temperature of aluminium and steel plate, and thickness reduction on the bond strength of the composites as well as on the formation of intermetallic interface layers is analysed by shear tests and metallographic evaluations of the interface.
... Bei Spannungen über 220 kV werden Bündelleiter verwendet, um dem Korona-Effekt zu entgegnen. ... more ... Bei Spannungen über 220 kV werden Bündelleiter verwendet, um dem Korona-Effekt zu entgegnen. ... Supraleitende Kabel sind zurzeit im Netz noch in Erprobung. 6.3 Werkstoffe für Energiespeicherung (Batterien und Akkus) ...
ABSTRACT Es werden die fertigungstechnischen Herausforderungen im Hinblick auf Umweltschonung bei... more ABSTRACT Es werden die fertigungstechnischen Herausforderungen im Hinblick auf Umweltschonung bei verbesserter Crash-Sicherheit sowie aktuelle Lösungen für die umformtechnische Fertigung von leichten Automobilkarosserien im Überblick dargestellt. Ausgehend vom stofflichen Leichtbau durch Verwendung hochfester Stahlfeinbleche oder Leichtmetalllegierungen werden die umformtechnischen Schwierigkeiten aufgezeigt. Hauptaugenmerk wird aber auf jene Fertigungstechnologien gelegt, die eine deutliche Senkung des Fahrzeuggewichts bei gleicher oder erhöhter Steifigkeit bzw. Festigkeit ermöglichen. Neben der Blechverarbeitung werden auch Ansätze für massivumgeformte Bauteile aufgezeigt. Manufacturing challenges with respect to environmental protection and improved crash performance as well as actual solutions for metal forming technologies are compared to produce light-weight vehicle bodies. Forming problems related to materials oriented concepts by using of high strength steel sheets or light metal alloys are shown. Main focus is, however, put on those forming technologies, which lead to significant reductions of car weight at almost the same or even better stiffness and strength behaviour. Beside sheet metal forming also concepts for massive formed components are presented.
This paper presents an experimental investigation of friction in hot forging of AA6082, which is ... more This paper presents an experimental investigation of friction in hot forging of AA6082, which is a standard forging alloy in automotive engineering, mechanical engineering and in naval architecture, by employing a modified ring-on-disc test. The experiments were performed with three different commercial graphite-based lubricants and at various loads, sliding velocities and specimen surface conditions. In addition, some tests were performed without lubrication.
The impact resistance and the fracture behaviour of sheet metals under ballistic impact condition... more The impact resistance and the fracture behaviour of sheet metals under ballistic impact conditions which depend significantly on some material characteristics like cold work hardening and ductility are important for the development of passive protection systems for passenger cars. To establish the impact of a projectile during penetration of a sheet metal, a FEM model was generated using the commercial FEM-code Abaqus/Explicit. The model was evaluated with real shooting experiments, where the impact behaviour of sheets made of different steels was tested at a shooting stand and the penetration was analysed metallographically. The evaluation showed that reasonable results from the simulation can only be achieved using a damage model concept and when the deformation of the bullet is considered in interaction with the deformation of the sheet metal. The variation of sheet thickness in the simulation shows good agreement with empirically developed formulations to predict the penetration power of a full metal jacket in steel sheets. With the evaluated model, parameter studies were performed to investigate the energy loss during the impact of a projectile into steel sheets with different hardening rates. The studies show that FEM simulation can give good basic knowledge about the impact behaviour of a projectile into steel sheets and can help to achieve higher protection in conjunction with weight reduction in protected passenger cars.
A model is presented that describes the development of texture during the production process of b... more A model is presented that describes the development of texture during the production process of bake-hardening steel recrystallized in a batch-annealing furnace. Proper conditions are analyzed to generate a pronounced ␥-fiber texture and a "pancake microstructure" that shows superior deep drawability. The ␥-fiber texture is assumed to be caused by the interaction between tertiary precipitating aluminum nitride particles and the recrystallization process during heating in the furnace. Deep drawability is presented in terms of the logarithmic ␥and ␣-fiber X-ray intensity ratio. The computer simulation of the coupled aluminum nitride precipitation and recrystallization kinetics is based on an iterative procedure. A comparison between simulation results and available experimental data proves the ability of the model to predict the final deep drawability, taking into account the initial aluminum and nitrogen contents, the time/temperature history during slab reheating, hot rolling and coiling, the degree of cold reduction, and the heating rate during batch annealing. assignment, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6376. V. PLETENEV, Postgraduate Student, and N. ZOLOTOREVSKY, Associate aluminum and nitrogen precipitation kinetics throughout the Professor, are with the
Forging Aluminium a b s t r a c t In this paper a number of aluminium forging lubricants were tes... more Forging Aluminium a b s t r a c t In this paper a number of aluminium forging lubricants were tested with respect to their lubricating effect and their applicability in the production of parts with long flow paths. The tests were conducted on a custom built testing machine that simulates the parameters of industrial production. The lubricants were assessed considering the change of the coefficient of friction during the test and the influence on tool and workpiece surface. From the presented analysis, the most appropriate lubricant for the investigated process was found.
Der Eindringwiderstand und das Bruchverhalten von Feinblechen bei Beschuss mit Projektilen sind f... more Der Eindringwiderstand und das Bruchverhalten von Feinblechen bei Beschuss mit Projektilen sind für die Entwicklung passiver Schutzmaßnahmen entscheidend. Die wichtigsten Einflüsse auf das ballistische Verhalten von Legierungen werden übersichtlich und insbesondere hinsichtlich des Gefügeeinflusses näher dargestellt. Das Beschussverhalten von Feinblechen eines weichen Stahles, eines höherfesten Vergütungsstahles, einer Aluminiumlegierung und eines metastabilen austenitischen Stahles wurde mit realen Beschusstests ermittelt und die Eindringwirkung metallografisch analysiert. Vergleichend dazu wurden Kragenziehversuche und numerische Simulationen zur Abschätzung des Ein dringverhaltens unterschiedlicher Werkstoffe durchgeführt.
Die Abbildung einer gewünschten Geometrie mittels Schmieden aus einem zylindrischen Vormaterial i... more Die Abbildung einer gewünschten Geometrie mittels Schmieden aus einem zylindrischen Vormaterial ist meist nicht in einem einzigen Schritt möglich. Für nahezu 90 % der Schmiedestücke müssen vor Erreichen der Endkontur eine oder mehrere Zwischenformen erzeugt werden, um eine Materialverteilung zu erhalten, die ein faltenfreies Bauteil mit optimaler Materialverteilung im letzten Schmiedeschritt gewährleistet. In der vorliegenden Arbeit wird am Beispiel des Schmiedens eines Pleuels eine einfache Vorgehensweise zur Vorformoptimierung beschrieben, die auch für die praktische Anwendung im täglichen Fertigungsbetrieb geeignet ist. Für den untersuchten Pleuel konnte so mit einem Arbeitsaufwand von wenigen Tagen eine Vorform gefunden werden, die im Vergleich zur bisherigen Gestaltung eine Materialeinsparung von 15 % und damit verbunden eine erhebliche Verringerung des Gesenkverschleißes an der Gratbahn ermöglicht.
Schrauben aus hochfesten Stählen und deren wirtschaftliche Fertigung unterliegen hohen Qualitätsa... more Schrauben aus hochfesten Stählen und deren wirtschaftliche Fertigung unterliegen hohen Qualitätsansprüchen und werden ständig weiter verbessert. Für hochfeste Schrauben werden üblicherweise MnB-und 1 %Cr-Stähle im vergüteten Zustand verwendet. Als kostengünstige Alternativen gelten thermomechanisch gewalzte Stähle, Dualphasenstähle und AFP-Stähle, die ohne zusätzliche Wärmebehandlung (Vergütung) hergestellt werden können. Ausgehend von der Beschreibung der metallurgischen und walzbedingten Einflüsse bei der Drahtherstellung und deren Auswirkungen auf die Umformbarkeit bei der Schraubenherstellung werden die alternativen Stahlgüten vergleichend dargestellt. Ergänzend dazu werden die verfahrenstechnischen Optimierungsmöglichkeiten bei der Schraubenfertigung betrachtet, wobei primär der Vorzug, die Eigenspannungsentwicklung und die Wärmebehandlung untersucht werden. Durch FE-Simulationen werden die Fertigungsschritte analysiert und mittels Schädigungsmodellen die Grenzen der Umformbarkeit aufgezeigt.
In der Vergangenheit wurden zahlreiche Fließbedingungen für das Verdichten von pulvermetallurgisc... more In der Vergangenheit wurden zahlreiche Fließbedingungen für das Verdichten von pulvermetallurgischen (PM) Werkstoffen entwickelt. Die meisten dieser Modelle basieren auf einem modifizierten "von Mises"-Ansatz. In der vorliegenden Arbeit werden unterschiedliche Fließbedingungen Shima & Oyane, Kuhn & Downey, Gurson, Gurson-Tvergaard und Doraivelu) in das Finite-Elemente (FE)-Programm Deform3D™ implementiert und untereinander verglichen. Die berechneten Werte werden mit Zylinderstauchversuchen mit unterschiedlicher Spannungstriaxialität verglichen. Durch die Überprüfung der FE-Rechnung anhand der Versuchsdaten wird gezeigt, dass unter den betrachteten Materialgesetzen das Modell nach Gurson-Tvergaard mit dichteabhängigen Parametern die Verdichtung von PM-Materialien am besten beschreibt. Implementation of Yield Functions in the FEM Software DEFORM 3D™ to Simulate the Densification of PM Materials. To determine the initiation of yielding and compaction of metal powder components, various different yield models have been proposed. Most of these models are based on a modified "von Mises" criterion. To obtain sufficient results from the Finite Element (FE) calculation of the compression process of PM parts, advanced material models (Shima & Oyane, Kuhn & Downey, Gurson, Gurson-Tvergaard and Doraivelu) have been implemented into the FE code Deform3D™. The calibration of these models is done by cylindrical compression tests with different stress triaxiality. The results of these tests show that the conformity between the calculated results based on the material model of Gurson-Tvergaard with density dependent parameters show a better fit than the results of the other investigated yield functions.
Lightweight thin walled structures are primarily dimensioned for stiffness of the whole construct... more Lightweight thin walled structures are primarily dimensioned for stiffness of the whole construction and less for material resistance. Usual design concepts for improving the stability behaviour of metal sheets introduce the configuration of fins, stiffeners, beads or embossing patterns. However these methods not only increase the moment of inertia but also the weight of the component. In this paper an alternative method for inserting residual stresses is presented and the influence of the static and dynamic behaviour is shown. Local laser spots and laser lines are introduced in order to achieve proper distributions of residual stresses. The effect on fundamental frequency and buckling resistance was investigated on steel sheets of 280 mm x 280 mm and a thickness of 0.75 mm in a special testing rig. Buckling load and mid-point displacement were measured by a LVDT-system. Correlations between residual stresses, fundamental frequency and buckling resistance could be found. During buckling tests the uniaxial applied load vs. mid-point deflection was measured. In order to illustrate the improvements of the buckling load, fundamental frequency and residual stresses have been analysed. In conclusion, the laser treatment and the insert of residual stress patterns by laser treatment, respectively, is a promising method to increase the static and dynamic behaviour for thin walled metal sheets.
Science and Technology of Welding and Joining, 2002
ABSTRACT The long range diffusion of rapidly diffusing elements in dissimilar welds, which occurs... more ABSTRACT The long range diffusion of rapidly diffusing elements in dissimilar welds, which occurs during heat treatment and in service exposure, initiates heavy microstructural changes on both sides of the weld. Various carbides and nitrides either dissolve or precipitate as a function of the distance from the fusion line. The type and amount of these particles can be predicted by a numerical method for solving problems of simultaneous precipitation and diffusion. Predicted precipitate distributions for a 2·25Cr/9Cr and a 2Cr/0·5CrMoV weld are verified using experimental data obtained with analytical and energy filtering transmission electron microscopy. The phase diagrams for the high chromium side and the low chromium side of the welds are evaluated and compared with the experimentally determined precipitate distribution.
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Papers by B. Buchmayr