Search results for "Metallurgy"
showing 10 items of 1419 documents
Self-piercing riveting for aluminium alloys-composites hybrid joints
2008
In the paper, the growing interest on hybrid joints developed between composite panels and aluminium alloys blanks is focused. The self-piercing riveting operation is considered and its feasibility for the proposed joints verified. The most relevant process parameters were investigated in order to determine a suitable process window and, what is more, the mechanical performances of the developed joints were investigated in order to determine process parameters aimed to maximise them. Finally, the failure mechanics of the obtained joints were considered in order to highlight the mechanisms which occur and determine the lost of the load carrying capability of the joints. The developed experim…
Friction stir welding of tailored joints for industrial applications
2009
Friction stir welding (FSW) is an energy efficient and environmentally "friendly" (no fumes, noise, or sparks) welding process, during which the workpieces are welded together in a solid-state joining process at a temperature below the melting point of the workpiece material under a combination of extruding and forging. Since its invention in 1991 by TWI, such process has been reaching a continuously increasing popularity among aerospace, automotive and shipbuilding industries due its capability to weld unweldable or difficult-to-weld light alloys in different joint morphologies. In this paper a wide experimental campaign is carried out in order to obtain T and lap joints characterized by d…
On the FSW of AA2024-T4 and AA7075-T6 T-joints: an industrial case study
2009
In this paper, the authors present the results of a wide experimental campaign on aeronautical T-shaped parts of industrial interest characterized by dissimilar materials for the skin and stringer. The friction stir welding process engineering was developed with the aim to determine the specific process parameters determining the soundness on the obtained T-parts both from the metallurgical and mechanical point of view. Furthermore, the performance of the obtained T-joints was investigated.
Optimizing the H3PO4 leaching conditions of post-precipitated sewage sludge using response surface methodology
2018
The leaching procedure of post-precipitated aluminium phosphate sludge with dilute phosphoric acid was developed. The leaching offers a route to recover both critical phosphorous from sewage sludge and the metal used in precipitation. Using phosphoric acid as leaching solution makes it possible to continue the recovery process without the need to remove chloride or sulfate anions. The optimization of the leaching was based on experimental three-level-four-variable central composite face-centered design. The four variables included were acid concentration, volume of acid, temperature and time of leaching. The leaching was conducted for dewatered and water-containing sludge (total solid conte…
Stabilisation of MSWI bottom ash with sulphide-rich anaerobic effluent.
2007
Effluent of an anaerobic sulphate-reducing wastewater treatment process was used to stabilise bottom ash. The effect of stabilisation on the concentration and binding of Ca, P, S, Cu, Pb, Zn, As, Cr, and Mo were studied by comparing results of sequential extraction from fresh and stabilised bottom ash. The stabilisation treatment improved the retention of Ca, Cu, Pb, S, and Zn in bottom ash compared to a treatment with ion-exchanged water. In addition to retention, Cu, S, and Zn were accumulated from the anaerobic effluent in the bottom ash. Concentrations of As, Cr, and Mo remained on the same level, whereas leaching of P increased compared to control treatment with ion-exchanged water. Im…
Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants
2012
During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χ(fd)), and temperature dependence of magnetic susceptibility. Mineralogical and geochemical analyses included scanning electron microscopy with energy dispersive spectroscopy, microprobe analysis and X-ray diffraction. The TMPs in fly ash from hard coal combustio…
The miniaturised emission chamber system and home-made passive flux sampler studies of monoaromatic hydrocarbons emissions from selected commercially…
2017
Abstract The estimation of the emission rate of organic compounds released from various types of indoor materials can be performed using stationary environmental test chambers (ETC) classified as ex-situ methods or small-scale portable analytical devices based on the use of passive technique at the stage of analytes sampling from the gaseous phase (in-situ methods). The paper presents results of emissions of selected organic compounds from the monoaromatic hydrocarbons group (benzene, toluene, ethylbenzene, p,m-xylene and styrene) emitted from the surfaces of various types of commercially-available floor coverings and the underlay made of polyurethane foam which might be installed indoors u…
Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L.) Wood
2015
Linear friction welding of wood is a bonding process applied to wood and during which a stiff bond line is formed by the softening and rehardening of wood components to form a composite material composed mainly of wood fibres embedded in a modified lignin matrix. Unfortunately, the bonds tend to spontaneously delaminate or lose their strength when exposed to moist conditions. Some approaches were previously applied to overcome this problem, but so far a suitable solution has not been found. This paper presents results of applying post-welding thermal modification to reduce the moisture sensitivity of welded wood. The experiments included welding of birch wood, thermal modification under sup…
Analysis of the chemical and microstructural modifications effects on the hydro-mechanical behaviour of a lime-treated clay
2019
The paper presents the results of a characterization of kinetic characteristics of pozzolanic reaction with the aim to investigate the time-dependent modification of clay properties as a consequence of mixing with lime. Results of chemical analyses are in agreement with the increase of mechanical properties and with the observed microstructure modifications up to one year of curing time. The rate of development of pozzolanic reactions seems to be almost constant while the time required for their completion is dependent on the lime content. Pozzolanic products are responsible for the time reduction of swelling strain upon saturation as well as for the increases of yielding stress, stiffness …
Mechanical properties and microstructural study of homogeneous and heterogeneous laser welds in α, β,and α + β titanium alloys
2018
International audience; Heterogeneous welding has been investigated for three different couples of titanium alloys: α/α + β, α/β,andα + β/β. Plates of 100 × 60 mm and 1.6 or 1.8 mm thick were welded with a Yb:YAG laser. Tensile tests show that the resistance of the heterogeneous welded specimens was generally controlled by those of the weakest material except for the α + β/β where the ultimate tensile strength was approximately equal to the average value of both materials. In every case, the elongation of the welded sample was found to be smaller than that of the base metals. The rupture generally took place outside the weld metal and was found to be most of the time located in the alloy ha…