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LASER-Based Manufacturing as a Green Manufacturing Process
Published in R. Ganesh Narayanan, Jay S. Gunasekera, Sustainable Material Forming and Joining, 2019
Ashish K. Nath, Sagar Sarkar, Gopinath Muvvala, Debapriya Patra Karmakar, Shitanshu S. Chakraborty, Suvradip Mullick, Yuvraj K. Madhukar
Kujanpää (2014) has reported welding of austenitic steel up to 60 mm thickness by multipass hybrid laser–arc welding, minimizing the solidification cracks by controlling the microstructure by process optimization. High-power diode lasers of improved beam quality being currently developed are also being evaluated in welding of thick metallic sections in comparison to more established CO2, Nd:YAG and fiber lasers (Alcock and Baufeld 2017; Köhler et al. 2005). Alcock and Baufeld (2017) demonstrated autogenous welding of 304L stainless steel plates up to 12 mm thickness with 15 kW CW diode laser which could be focused to ~1.2 mm spot diameter. Their results suggest that for welding of plates in the 10 mm thickness range, the more economic diode laser systems may become a competitor to other systems with high-quality laser beams which may be more expensive in both procurement and operation. Successful welding of many dissimilar materials like CP Ti and steel (Chen et al. 2016; Shanmugarajan and Padmanabham 2012), AZ31B magnesium alloy to 316 stainless steel (Casalino et al. 2017), aluminum to stainless steel with preplaced activating flux (Ezazi et al. 2015; Sun et al. 2015), tantalum to titanium (Grevey et al. 2015), niobium to Ti–6Al–4V, (Torkamany et al. 2016), steel to copper (Kuryntsev et al. 2017).
Modelling of exposure to respirable and inhalable welding fumes at German workplaces
Published in Journal of Occupational and Environmental Hygiene, 2019
Benjamin Kendzia, Dorothea Koppisch, Rainer Van Gelder, Stefan Gabriel, Wolfgang Zschiesche, Thomas Behrens, Thomas Brüning, Beate Pesch
We took advantage of a categorical variable in MEGA, which was used by the metrologists to assign the welding or cutting of metals to commonly used processes. High fume emission processes include FCAW, metal active gas welding (MAG), metal inert gas welding (MIG), shielded metal arc welding (SMAW), and torch cutting. Furthermore, other welding processes include TIG, resistance welding, laser welding, submerged arc welding, plasma welding, autogenous welding, plasma cutting, flame spraying, plasma spraying, and arc spraying. Four consumable categories for dominant welding processes (MAG, MIG, TIG, SMAW) were defined. The three common consumables were mild steel, stainless steel, and aluminium (Al). The fourth category, labeled “other/mixed content” includes miscellaneous consumables or data for which the consumable was not identified. The metal content (%) was documented in MEGA for both the consumable and the base metal. We classified consumable electrodes as stainless steel if the chromium (Cr) or/and nickel (Ni) content exceeded 10%. Otherwise, ferrous consumables were classified as mild steel. The category “high Al” means a content of at least 95%. In the case of processes that did not use consumable electrodes, this classification was applied to the base material.
Mechanical behavior of friction stir butt welded joints under different loading and temperature conditions
Published in Mechanics of Advanced Materials and Structures, 2022
Lucas Pinto, Gonçalo Cipriano, Daniel F. O. Braga, Catarina Vidal, Miguel A. Machado, Arménio Correia, Virgínia Infante
Aluminum and its alloys have seen their application in multiple industries increase over the last years, as a result of the development of a joining process that enables the joining of such metallic alloys with excellent mechanical properties: Friction Stir Welding (FSW). FSW is a solid-state welding process during which melting of the base material does not occur. This allows aluminum alloys that were thought to be not weldable to be welded [1]. As for its working principles, a non-consumable, rotating, hardened steel tool, with a cylindrical shape constituted by a probe and a shoulder, is driven into the intended weld joint location until the probe has completely penetrated the material and the shoulder is in contact with the surface of the workpieces. The rotating speed of the tool generates heat (by interfacial and internal friction dissipation) and plastic strain that promote the weld of the workpieces. As the tool moves along the weld line (welding/travel speed), the material is stirred from the leading edge of the probe into its trailing edge, being thermo-mechanically processed, obtaining the desired weld by stirring/mixing the materials. Additionally, and since it is an autogenous welding process, no filler material is required to achieve the joining of the materials, hence allowing designs composed by lighter structural components. The joints achieved with FSW have excellent structural integrity and reduced weld affected microstructure zone, even enabling dissimilar material joining [2]. These factors combined have made FSW a prime candidate for structural applications in automotive, aeronautical and aerospace applications. As such, FSW has generated significant research and development effort to mature the technology, enable more applications and increase the technical and economic viability of the process. One more recent development is high-speed FSW, enabling high volume EV battery pack production with weld speeds up to 4.5 m/min [3, 4]. One important area of development in the field of FSW has been tools capable of optimizing process heat input, enabling more material combinations, higher performing joints, or higher speed welds. Tools such as Bobbin Tool and Stationary Shoulder Tool, lead to derivatives of FSW, such as Bobbin Tool FSW (BTFSW) and Stationary Shoulder (SSFSW). Sejani et al. [5] reviewed the recent developments in SSFSW and compared resulting joints and process with BTFSW, showing that SSFSW leads to finer more optimized microstructures. Besides tooling, process control has also been a point of focus of recent research, to enable and enhance self-supported FSW, non-weld-thinning FSW and frictional stir-based remanufacturing [6].