scholarly journals On the Elastoplastic Behavior of Friction Stir Welded Tailored Blanks for Single Point Incremental Forming

2021 ◽  
Author(s):  
Fausto Tucci ◽  
António Andrade-Campos ◽  
Sandrine Thuillier ◽  
Pierpaolo Carlone

The current market requirements are increasingly pushing the industry towards the manufacturing of highly customized products. Tailored blanks are a class of sheet metals characterized by the local variation of properties, attributable to the presence of different materials, different thickness distribution, and thermal treatments. In the manufacturing of tailored welded blanks, welding and forming processes cover a central role. In this framework, friction stir welding demonstrated to be a suitable candidate technology for the production by joining of tailored blanks. Indeed, sheet metals welded by this solid-state welding process typically exhibit high formability when compared to the conventional welding methods. Due to the improved formability, a good deal of attention has been recently given toward the single point incremental forming (SPIF) process and its integration with FSW. Remarkable efforts have been dedicated to the numerical modeling of the SPIF of metallic alloy sheets jointed by FSW. The main criticisms in these models are related to the definition of the mechanical properties of the materials, which are affected by the structural alteration induced by the FSW. The present work aims to model the local alterations in the mechanical properties and to analyze how these local characteristics affect the formability of the blanks. With this purpose, a 20 mm wide sample collected from a FS welded blank of aluminum alloy AA6082 has been modeled using the mechanical properties variation achieved in a previous work. The influence of this local variation in properties has been assessed using a Finite Element Model Updating strategy.

Author(s):  
Shalin Marathe ◽  
Harit Raval

Abstract The automobile, transportation and shipbuilding industries are aiming at fuel efficient products. In order to enhance the fuel efficiency, the overall weight of the product should be brought down. This requirement has increased the use of material like aluminium and its alloys. But, it is difficult to weld aluminium using conventional welding processes. This problem can be solved by inventions like friction stir welding (FSW) process. During fabrication of product, FSW joints are subjected to many different processes and forming is one of them. During conventional forming, the formability of the welded blanks is found to be lower than the formability of the parent blank involved in it. One of the major reasons for reduction in formability is the global deformation provided on the blank during forming process. In order to improve the formability of homogeneous blanks, Single Point Incremental Forming (SPIF) is found to be giving excellent results. So, in this work formability of the welded blanks is investigated during the SPIF process. Friction Stir Welding is used to fabricate the welded blanks using AA 6061 T6 as base material. Welded blanks are formed in to truncated cone through SPIF process. CNC milling machine is used as SPIF machine tool to perform the experimental work. In order to avoid direct contact between weld seam and forming tool, a dummy sheet was used between them. As responses forming limit curve (FLC), surface roughness, and thinning are investigated. It was found that use of dummy sheet leads to improve the surface finish of the formed blank. The formability of the blank was found less in comparison to the parent metal involved in it. Uneven distribution of mechanical properties in the welded blanks leads to decrease the formability of the welded blanks.


Author(s):  
Mohammad Ali Davarpanah ◽  
Shalu Bansal ◽  
Rajiv Malhotra

Incremental forming is an emerging technique for reducing the cost of tooling, increasing the flexibility and reducing the thermal energy usage in forming of thermoplastic polymer surfaces. This paper examines the effect of Single Point Incremental Forming (SPIF) on the mechanical properties of a semi-crystalline Polyamide (Nylon 66) material. The effects of incremental depth and tool rotation speed on these properties, and on the sheet temperature during forming are quantified. Differential Scanning Calorimetry and X-ray Diffraction are performed to understand changes in crystallinity and chain orientation of the polymer due to SPIF. It is found that the formed material has a substantial higher toughness and ductility, but reduced yield stress and Young’s modulus, as compared to the formed material. Stress relaxation tests show similar relaxation behavior for the formed and unformed polymer. The effect of SPIF on the chain orientation and its link to the mechanical properties are discussed.


Author(s):  
Matteo Benedetti ◽  
Vigilio Fontanari ◽  
Bernardo Monelli ◽  
Marco Tassan

In this article, the single-point incremental forming of sheet metals made of micro-alloyed steel and Al alloy is investigated by combining the results of numerical simulation and experimental characterization, performed during the process, as well as on the final product. A finite element model was developed to perform the process simulation, based on an explicit dynamic time integration scheme. The finite element outcomes were validated by comparison with experimental results. In particular, forming forces during the process, as well as the final shape and strain distribution on the finished component, were measured. The obtained results showed the capability of the finite element modelling to predict the material deformation process. This can be considered as a starting point for the reliable definition of the single-point incremental forming process parameters, thus avoiding expensive trial-and-error approaches, based on extensive experimental campaigns, with beneficial effects on production time.


2014 ◽  
Vol 611-612 ◽  
pp. 1079-1087 ◽  
Author(s):  
Mikel Ortiz ◽  
Mariluz Penalva ◽  
Mildred J. Puerto ◽  
Petr Homola ◽  
Václav Kafka

The lightweight metal alloy Ti-6Al-4V is widely used in the aeronautical industry due to its excellent mechanical properties. However, it is known the difficulty to deform Ti-6Al-4V sheets at room temperature because of its microstructure conditions. The present work focuses on the evaluation of formability of Ti-6Al-4V sheets using hot single point incremental forming (SPIF) process which it seems appropriate to produce small batches of parts due to its flexibility as it allows a significant reduction of costs and lead times. In order to characterize the SPIF of Ti-6Al-4V under hot forming conditions, a set of forming trials evaluation tests was carried out. The obtained results have allowed identifying the key process features and have demonstrated the potential of the proposed approach to hot form of small amounts of Ti-6Al-4V parts.


Author(s):  
Senthil Kumar Velukkudi Santhanam ◽  
Vigneshwaran Ganesan ◽  
Subramanian Pillappan Shanmuganatan

In the recent manufacturing trend and, in particular, in sheet metal forming, the requirement of customized production is still growing. Incremental forming is a special technique requiring no high capacity presses or set of dies, thus meeting the increasing demand for low volume production and rapid prototyping. The complex three dimensional parts of sheet metals are formed by the computer numerical control (CNC) movement of a simple generative hemispherical tool. In this paper, the single point incremental forming process is performed on friction stir processed AA 6063-O alloy. The process parameters for the experiment are taken based on L9 Orthogonal array. In this paper the maximum wall angle or the formability is investigated on a formed pyramid frusta. It is inferred that Friction stir process has improved the ductility of the aluminium alloy thus contributing to enhanced formability.


2017 ◽  
Vol 890 ◽  
pp. 362-366 ◽  
Author(s):  
Amar Al-Obaidi ◽  
Verena Kräusel ◽  
Dirk Landgrebe

The strategy in manufacturing hardened parts used in car bodies is to tailor the mechanical properties. This is done by combining together a high-strength region and a high-toughness region to ensure the crash performance required. Other successive secondary operations such as trimming, joining and welding can be improved as a result of the tailoring process. In this work, the mechanical properties of 22MnB5 alloy sheet material produced by single-point incremental forming have been tailored. For this purpose, the sheets were locally heated by induction during the forming process and subsequently cooled. The sheet temperature was controlled by the CNC milling machine feed rate and induction power. As a result, the produced tailored parts consist of three different regions: ductile, transition and hardened regions. The Vickers hardness values were 583 HV1 and 175 HV1 for the hardened and ductile regions, respectively. The proposed application allows forming and quenching at the same time without transfer and to reduce the process time.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 198
Author(s):  
Valentin Oleksik ◽  
Dan Dobrota ◽  
Sever-Gabriel Racz ◽  
Gabriela Petruta Rusu ◽  
Mihai Octavian Popp ◽  
...  

The present paper aims to study the behaviour of Metal Active Gas (MAG) tailor welded blanks during the single point incremental forming process (SPIF) from an experimental point of view. The single point incremental forming process was chosen for manufacturing truncated cone and truncated pyramid shaped parts. The same material (S355) and the same thickness (0.9 mm) were selected for the joining of blank sheets because the main goal of the paper was to study the influence of the MAG welding process throughout the SPIF process. A Kuka robot, equipped with a force transducer and an optical measurement system were used for manufacturing and evaluating the parts by SPIF. The selected output data were major and minor strain, thickness reduction, forces and springback at the SPIF process. Another line test was performed to evaluate the formability in SPIF. The main conclusion of the paper is that during the SPIF process, fractures occur in one side welded blanks even at moderate wall angles, while in the case of double side welded blanks there is a decrease of formability but parts can still be produced at moderate angles (55 degrees) without any problems.


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