Este trabalho visou entender e avaliar a resistência mecânica da junção de chapas de aço obtidas pelo processo de União de Chapas por Conformação a Frio (UCCF). Esse processo é conhecido no meio industrial pelo termo em inglês: clinching ou press joining. O formato de união cilíndrico, também conhecido como Round, foi selecionado para unir os corpos de provas. As uniões metálicas ensaiadas foram fabricadas com aço de baixo teor de carbono sem camada superficial de proteção (170MPa de limite de escoamento). O material escolhido é de comum utilização na indústria automotiva. Duas espessuras diferentes foram avaliadas: 0,8mm e 1,2mm. Um completo procedimento foi criado para determinar os parâmetros ideais do processo UCCF baseado nos critérios de falha existentes na literatura e na experiência do fornecedor do equipamento. A união em estudo foi submetida, experimentalmente, a cargas multiaxiais com o auxílio de um dispositivo baseado no ensaio de Arcan para possibilitar uma condição de carga combinada, onde foi possível identificar graficamente o comportamento estrutural do corpo de prova em estados de carregamento que variam de tração (normal à superfície do ponto) até cisalhamento (perpendicular à superfície do ponto). Os valores de resistência mecânica encontrados foram de 1,13kN (mínimo) a 2,55kN (máximo) para as chapas de aço com espessura de 0,8mm e de 1,89kN (mínimo) e 3,18kN (máximo) para as chapas de 1,2mm. Um estudo comparativo com Solda Ponto por Resistência Elétrica (SPRE) foi realizado. A UCCF alcançou resultados de 47,68% dos valores obtidos para a SPRE para chapa com espessura de 0,8mm e 37,78% para chapas de 1,2mm. / The purposes of this work were understand and evaluate cold forming sheet metal joining of steel plates mechanical resistance. This process is well known as clinching or press joining. Round clinching element was selected to be used on all tested specimens due to its industry suitability. The metallic specimens were built on mid carbon steel without zinc coat protection (Yield Stress: 170MPa). This is a common material on automotive industry. Two different thicknesses were evaluated: 0.8mm and 1.2mm. A full procedure to determine ideal clinching parameters was created based on available literature information and clinching supplier know-how. All union technology was experimentally submitted to multiaxial loads using device based on Arcan concept. Joining mechanical behavior curves were plotted from traction (normal to element joint surface) to shear (perpendicular to element joint surface) loads. As a result, 0.8mm thickness steel plates achieved load values from 1.13kN (minimum) to 2.55kN (maximum), 1.2mm thickness steel plates achieved values from 1.89kN (minimum) e 3.18kN (maximum). A comparative study was made with Electric Resistance Spot Weld (ERSP). Clinching joining achieved results as 47.68% and 37.78% of ERSP loads for 0.8mm and 1.2mm thickness steel plates respectively.

The project elaborated in frame of engineering studies branch M-STG proposes a technology of connecting pin – structural steel 11 320 5R. The technological calculations were performed and the production procedure was devised on the basic on the literary study of cold bulk forming with concentration on the extrusion and upsetting. Forming machine was design HATEBUR BKA-3 with a nominal power 1800 kN. The component is made in four forming operations. Extruder will be made from tool steel 19 830, extrusion die from tool steel 19 830 and clamp ring from tool steel 19 740.

In North America, cold-formed square and rectangular hollow sections (collectively referred to as RHS hereinafter) of commonly specified cross-sectional dimensions are produced using either the indirect-forming approach or the direct-forming approach. The indirect-forming approach, as the conventional approach of the two, consists of three steps: (i) roll-forming the coil material progressively into a circular hollow section; (ii) closing the section using electric resistance welding (ERW); and (iii) reshaping the circular section into the final square or rectangular shape. On the other hand, the direct-forming approach, as the new approach of the two, roll-forms the coil material directly into the final square or rectangular shape. RHS with similar cross-sectional dimensions but different production histories (i.e., different cold-forming approaches and post-production treatments) are expected to have significantly different material and residual stress properties. However, RHS design provisions in the existing North American steel design standards (AISC 360-16 and CSA S16-19) are in general developed based on research on indirect-formed RHS and currently do not differentiate RHS cold-formed by different approaches. Based on the research presented in Chapter 1 of this thesis, comparing to indirect-formed RHS, direct-formed RHS in general contain lower levels of residual stresses around cross sections, since the flat faces are not severely cold worked during production. This in turn affects member behaviours under compressive and flexural loadings. The test results presented in Chapters 2 and 4 show that direct-formed RHS have superior stub column and beam behaviours, comparing to their indirect-formed counterparts. In particular, the stub column and beam testing programs, covering a wide range of cross-section dimensions and two strength grades (nominal yield stresses of 350 and 690 MPa), show that the slenderness limits in the existing North American steel design standards are excessively conservative for direct-formed RHS, resulting in unnecessary penalty and member strength underestimation. As a result, the existing design formulae are not suitable for direct-formed RHS. In response to this, subsequent finite element (FE) parametric investigations are performed and presented in Chapters 3 and 5. Modified stub column and beam design recommendations for direct-formed regular- and high-strength RHS are proposed. The effects of post-cold-forming hot-dip galvanizing on material properties, residual stresses, stub column behaviours and beam behaviours of direct-formed regular- and high-strength RHS are also studied in Chapters 1-5 of this thesis. Similar to the application of the heat treatment per ASTM A1085 Supplement S1 or the Class H finish per CSA G40.20/G40.21, post-cold-forming galvanizing improves the stub column (Chapter 2) and beam (Chapter 4) behaviours of direct-formed RHS via effective reduction of residual stresses (Chapter 1). Based on subsequent FE parametric investigations, modified stub column and beam design recommendations catering to galvanized direct-formed RHS are proposed in Chapters 3 and 5. / Graduate

The master’s thesis presents a concept for spring bush manufacturing made of 11 320-5R steel by cold forming. Five steps process of manufacturing is based on the literary studies and technical calculations. The multistage cold forming machine HATEBUR AKP 5-5 was chosen for selected option of forming technology. As raw material was used cylinder shape with diameter of 26 mm and length of 29 mm. The economic results fix the price of one component of 16 CZK for annual dose 250 000 pieces.

Dieser Vortrag beschreibt ein methodisches Vorgehen zur Auslegung von Bauteilen, die von mehreren Eingangsgrößen und mehren Zielgrößen bestimmt sind. Als Praxisbeispiel wird eine dünnwandige Mittnehmerwelle untersucht. Im Automotivbereich besteht auf Grund der Forderungen nach Leichtbau und höherem Leistungsgewicht verstärkt der Wunsch nach einer hohen Auslastung über das ganze Bauteil hinweg. Eine Gewichtsreduktion kann durch Materialeinsparungen an unkritischen Stellen, wie zum Beispiel im Wellenkern einer Zahnwelle, erreicht werden. Die Verwendung von dünnwandigen Rohren als Ausgangsmaterial, aus denen lastangepasste Zahnprofile umformend hergestellt werden, versprechen eine deutliche Steigerung der Drehmomentübertragbarkeit bezogen auf den Materialeinsatz. Dazu wird eine neue Verzahnungsgeometrie entwickelt. Das Profil wird über eine Vielzahl an Parametern definiert, welche die Form und damit die Drehmomentübertragbarkeit beeinflussen. Durch die Verwendung einer bidirektionalen Schnittstelle kann eine Zahn-Geometrie in einem CAD-Programm mit einem FEM-Programm gekoppelt werden. Es zeigt sich, dass sich einige Geometrieparameter bereits durch die Wahl des Ausgangsrohres ergeben oder vorab festgelegt werden können. Mit vorgegebenem Außendurchmesser und Wandstärke des Ausgangsrohres sowie der Zähnezahl verbleiben bei dieser Profilform nur weitere fünf Parameter, welche hinsichtlich der Drehmomentübertragbarkeit zu optimieren sind. Mit Hilfe von numerischen Variantenberechnungen, welche sich nach den Vorgaben eines statistischen Versuchsplanes / Design of Experiments durch Veränderung der Parameter ergeben, kann ein mathematisches Ersatzmodell gebildet werden. Dieses beschreibt die (Wechsel-)Wirkungen der Eingangsgrößen auf die Ausgangsgrößen, wie zum Beispiel der Einfluss des Fußkreisdurchmessers und des Eingriffswinkels auf die dynamische Beanspruchbarkeit. Mit Hilfe von Optimierungsalgorithmen kann ein Optimum der Parameter an Hand des Ersatzmodelles ohne erneute aufwändige FEM-Berechnung gefunden werden.

The purpose of this work is to introduce explicit finite element method (FEM) and to familiarize with commercial software tools witch are capable to perform simulations. The technological conditions and the scope of application of roller burnishing are described in subsequent part. The simulation model of roller burnishing was created. Software ANSYS LS-DYNA was used to make computations. The results of simulation and technical and economical benefits of roller burnishing are presented in the conclusion.