Cold spraying has great potential for additive manufacturing, especially of oxidation-sensitive metals, because the material is not melted and significantly higher deposition rates can be achieved than with conventional additive manufacturing processes such as selective laser melting or direct metal deposition. Titanium is regarded as a high-performance engineering material due to its unique combination of properties, including good corrosion resistance, biocompatibility and high strength at comparatively low density. However, due to its high price, it appears reasonable for many applications to use material compounds in which titanium is only used on the surface of the workpiece, while less expensive materials such as aluminum are used for the remaining volume. In the present work, cold sprayed pure titanium coatings were deposited on Al substrates and then formed to defined 3-dimensional final contours by die forging and rotary swaging. Different porosities were selectively set in order to evaluate their influence on the coating adhesion and cohesion in the forming process. Pre-consolidation of the coatings and the use of Al/Ti interlayers proved to be promising strategies.

This study discusses the development of a numerical simulation model to predict press force and final deformation induced by welding-to-forming process chain with experimental validation. The numerical models of welding and forming were developed in sequence by utilizing two specialized virtual manufacturing software family namely Simufact.Welding (SW) and Simufact.Forming (SF). In the non-linear thermomechanical simulation, the GMAW process was firstly executed on a butt joint of mild steel S235 with thickness of 2 mm followed by bending process whereby the plate and dies geometry were modelled based on the actual dimension and the weld bead geometry was modelled by means of simplified shape. The result of transient welding simulation was transferred to forming which considers the final deformation and effective stress. For achieving realistic transient temperature distribution, the heat transfer coefficients during the welding process were calibrated on specific points measured by using thermocouple with data logger. For verification purpose, a series of comprehensive welding experiments was executed using robotic system followed by the metal bending process using hydraulic press machine. It can be observed at the final deformation results that the difference between simulation using SF-SW and experiment showed an acceptable error percentage within the range of 4 to 12% on each measurement point and up to 7% in average. The press force prediction showed an error percentage of up to 10% at lower-to-medium and up to 17% at high stroke section. Hence, by referring to the results, this study can be applied to select a suitable press machine for this specific coupled process based on estimated load range.

Additive manufacturing of components has increased significantly in capacity; additional post-processes are usually required in order to use the components. A milling process is often used to create functional surfaces. The paper shows whether the additive manufacturing process has an influence on the milling process. For this purpose, additive manufacturing processes using powder and laser (SLM), powder and arc (3DPMD), as well as wire and arc (WAAM) of the same material are compared. Based on the microstructure and the different mechanical properties, the component properties are compared with each other and with conventional sheet metal. For this purpose, samples are cut from additively manufactured components and milled under identical conditions. The temperature and the milling forces are measured and evaluated. It is shown that the additive manufacturing process results in significant differences in machinability and that the mechanical properties alone do not provide sufficient information about the machinability.

This fundamental research aims to apply a numerical model of free grain growth theory using a self-developed algorithm. The algorithm will incorporate the free grain growth formula with significant parameters such as activation energy (Qa) and kinetic grain growth constant (K) selected from various sources specifically for austenitic stainless steel SS316L. The initial grain size (D0) parameter was validated experimentally. The predicted and verified final average grain sizes were compared at the heat-affected zone after welding with an acceptable error percentage of up to 6%, according to the findings.

Wire-arc additive manufacturing (WAAM) complex components can be built-up layer by layer from metallic construction materials. In this investigation two different WAAM processes with high built-up rates (CMT and pulsed GMAW) were compared in terms of geometry formation and component properties. The reference is a rectangular thin-walled geometry made of the austenitic stainless steel 316LSi (1.4430). During the welding process, the temperature development in the weld layer was measured. The experimental comparison of CMT (\({\text{R}}_{\text{m}}=630 {\text{MPa}}\)) and pulsed GMAW (\({\text{R}}_{\text{m}}=605 {\text{MPa}}\)) is completed by the determination of the mechanical properties using micro-tensile tests. Furthermore, the additive-manufactured walls were cold rolled with a subsequent heat treatment or hot rolled to provide proof of formability and forming induced property improvement.

Additive Manufacturing is an established process group that includes various technologies. In contrast to subtractive methods, complex components can be produced by applying layers of construction materials. In accordance with the standard VDI Guideline 3405, additive manufacturing technologies can be differentiated into wire- and powder-based technologies. The basis for these experimental investigations is a Wire Arc Additive Manufacturing (WAAM) process with a high build-up rate (Cold Metal Transfer - CMT) to produce a rectangular thin-walled component made of G4Si1 (1.5130). In order to analyze the influence of a subsequent forming process on the microstructural properties and the forming behavior of the components, compression tests were carried out. Therefore, cylindrical specimens were made out of the additively manufactured components by machining. To be able to take a possible anisotropy in the workpiece caused by the multi-layer welding into account, the samples were taken both along and across the welding direction. To evaluate the inhomogeneous component properties, cast specimens with a representative microstructure were produced by inductive melting of the filler material and subsequent a solidification with an appropriate cooling rate. In addition to the cold forming of the additively manufactured components, the investigation also includes hot forming and the influence of a corresponding heat treatment. The experimental examination was completed by the analysis of the microstructure of each material state. The aim of the research work was to prove the homogenization and optimization of the mechanical properties of additive manufactured components due to a subsequent forming process. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the 23rd International Conference on Material Forming.

The increased environmental awareness of politics and society is confronting the automotive and aviation industries with new challenges. This results in an increased need for research into new lightweight construction potentials. One of the most efficient lightweight materials is titanium. In particular, the high strength and corrosion resistance allows a wide range of applications. Nevertheless, titanium has a decisive disadvantage - its high material costs. One way of making the positive properties of titanium economically viable for industry is to combine it with less expensive materials such as steel or aluminum. For the present study, composite bodies of the steel S235 and titanium powder were produced by cold gas spraying.