Fast algorithms for material specific process chain design and analysis in metal forming - final report DFG Priority Programme SPP 1204

The book summarises the results of the DFG-funded coordinated priority programme \"Fast Algorithms for Material Specific Process Chain Design and Analysis in Metal Forming\". In the first part it includes articles which provide a general introduction and overview on the field of process modeling in metal forming. The second part collates the reports from all projects included in the priority programme

Forming Process Simulation for Fabrication Optimization in Areva Creusot Forge and Industeel

International audienceThe grain size of the austenitic stainless steel is an important issue for parts such as primary pipes in nuclear power plants and more globally for metal forming. Having tools which can predict at least the final grain size distribution for these materials is strongly required. It is in this frame that ACF worked for several years with other industrial and academic partners such as INDUSTEEL CRMC, Aubert & Duval, Ascometal, CEA Valduc and CEMEF Mines ParisTech on the simulation of the recrystallization (ReX) of 304L austenitic stainless steel. Recent developments allowed simulation in a full-field context of the static recrystallization (SRX) of 304L stainless steel including a crystal plasticity formulation in a finite element (FE) context in order to model precisely the grain deformation anisotropy. This crystal plasticity model includes a decomposition of the dislocation density in SSDs (Statistically Stored Dislocations) and GNDs (Geometrically Necessary Dislocations). Including the GNDs gave better results on the localization of the strain but also allowed to define more relevant nucleation criteria. During and after ReX, the grain growth phenomenon due to capillarity effects is also modelled. To take into account capillarity effects enables to reproduce precisely the final microstructure morphology (shape of the grains, equilibrium angles at multiple junctions...). This full-field approach gives very good results for the modelling of 304L stainless steel SRX. In parallel, at plants, forging and rolling processes need to be simulated in order to optimize fabrication sequences in terms of material distortion capability versus rheological properties of these materials and in terms of grain size with potential impact on ultrasonic inspection performance. In order to verify the process capability, a reduced ¼ scale component of 304L stainless steel primary pipes has been fabricated in a similar forging sequence. Study of the recrystallization aspect at different locations of the component was part of the objectives of the project. The paper gives a view of all combined approaches: theoretical approach by recrystallization modeling as well as simulation of forging and rolling sequences with Forge® software (coupled to a mean-field metallurgical model called Thermide) and fabrication of a reduced scale part with nozzles as a test before the fabrication of the final component

Modelling of forging processes assisted by piezoelectric actuators : principles and experimental validation

This paper presents the modelling of a forging processes assisted by a piezoelectric actuator (PA), which is used to generate specific low frequency vibration waveforms. Experimental results show that such waveforms reduce the necessary forging force during upsetting tests. The main problems which remain are defining the appropriate waveforms, predicting their influence on the process and the actuator and designing the control. Due to the complexity of the interactions between the different components of the system, a complete model of the process is needed. Such a model is developed here using an energetic macroscopic representation to preserve causality throughout the modelling. Simulation results are then compared to representative experimental results

Computer Applications in Metallurgical Research

This paper outlines the current efforts in computer applications in metallurgical research at the Defence Metallurgical Research Laboratory, Hyderabad. Work being done on armour penetration studies, optimization of armour profiles for fighting vehicles, computer control of multifunction 2000 tonne forge press, drawing of processing mechanism maps, process modelling of titanium sponge production and methods of curve fitting to experimental data, is described and briefly discussed

Micro-manufacturing : research, technology outcomes and development issues

Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Aeronautical engineering: A continuing bibliography with indexes (supplement 202)

This bibliography lists 447 reports, articles and other documents introduced into the NASA scientific and technical information system in June 1986

Framework for developing large-scale metal additive manufacturing (MAM) systems and procedures

Additive manufacturing (AM) is regarded as one of the most disruptive technologies of this era. However, the technology is still evolving, even as new applications continue to emerge, thus presenting an opportunity to manage disruptive changes more efficaciously, whilst strategically shaping critical innovation efforts. Accordingly, this study focusses on supplementary manufacturing requirements management (SMRM). Presently, maintenance challenges, such as the reworking of serviceable infrastructures and other similarly demanding industrial endeavours, contribute to higher costs, inefficiencies, and waste, with technical and other limitations, including disparate supply circumstances and demand patterns, further compounding issues. Underpinned by SMRM applications, the grounded theory (GT) method was applied, to construct a framework for developing large-scale metal AM (MAM) systems and procedures. Case data was derived from the development and commissioning of a unique system and its embodied concepts, which were predominantly enabled by commercial off-the-shelf (COTS) solutions, and subsequent testing and validation of the resulting open architecture (OA) bulk AM (BAM) platform. Empirical and numerical investigations were facilitated by an industrial titanium (Ti-6Al-4V) aerospace component, which demonstrated the suitability and effectiveness of the BAM platform for specific SMRM operations. While the physical and mechanical properties of derived BAM materials were characteristic, and within range of referenced ASTM standards, disparities between the predicted and quantified effects of reprocessing operations on the component necessitate further investigation. The main output of this study is a GT framework, which identifies six strategic developmental themes for more adoptable, compliant, functional, operable, systemical, and adaptable MAM solutions. Important priorities for improving interrelated system functions, procedures, and performance were also defined, alongside an original technical perspectives management concept, for navigating complex requirements in an evolving technology landscape, via the documentation, clarification, validation, and prioritisation of key elements that significantly impact planned innovations