| 1. |
- Bjurenstedt, Anton, et al.
(författare)
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Assessment of Quality when Delivering Molten Aluminium Alloys Instead of Ingots
- 2013
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Ingår i: Materials Science Forum. - : Trans Tech Publications. - 0255-5476 .- 1662-9752. - 9783037857663 ; 765, s. 266-270
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Tidskriftsartikel (refereegranskat)abstract
- Recycled aluminium alloys manufactured at Stena Aluminium, in Älmhult, Sweden, are delivered in special designed transport containers, called thermoses. Thermoses are best described as an insulating layer protected by a steel cover with a heat loss of about 5 degrees/h. Three thermoses are transported by a truck, giving the possibility for a total capacity of about 24 tonnes delivered aluminium just-in-time to the foundry. By delivering a full load of liquid aluminium, about 2 tonnes of carbon dioxide emissions are saved, compared with delivering ingots. The aim of the paper is to assess the quality benefits, in terms of inclusions sedimentation and mechanical properties, assured by delivering aluminiummelts instead of ingots. The results indicate that materials produced by just-in-time melt delivery have slightly improved quality compared to ingots. The trends are explained in terms of quality, density and bifilm indexes, based on microstructural observations as well as tensile test data analysis.
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| 2. |
- Bogdanoff, Toni, et al.
(författare)
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On the Effectiveness of Rotary Degassing of Recycled Al-Si Alloy Melts : The Effect on Melt Quality and Energy Consumption for Melt Preparation
- 2023
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 15:6
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Tidskriftsartikel (refereegranskat)abstract
- The effectiveness of rotary degassing on the defect formation and mechanical properties of the final casting of aluminium alloy EN AC 46000 was investigated, along with its impact on the energy consumption in the casting furnace. In the melt preparation prior to casting, the molten metal is usually transported from the melting furnace to the casting furnace with rotary degassing as a cleaning procedure. Under the conditions of this specific study, negligible degradation was observed in the mechanical properties of the final cast component in an aluminium EN AC 46000 alloy after removing the rotary degassing step in the process. Furthermore, removing the rotary degassing step led to a reduced temperature drop in the melt, thus minimizing the need for reheating (energy consumption) by up to 75% in the casting furnace. The reduced energy consumption was up to 124,000 kWh in yearly production in a 1500 kg casting furnace. The environmental impact showed a similar to 1500 kg reduction in CO2 for one 1500 kg electrical casting furnace in a year.
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| 3. |
- Boikov, Iouri, 1949, et al.
(författare)
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Variations in the electrical resistivity of La0.67Ca0.33MnO3 films and induced interconversions of ferromagnetic and nonferromagnetic inclusions in their bulk
- 2011
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Ingår i: Physics of the Solid State. - 1063-7834 .- 1090-6460. ; 53:10, s. 2168-2173
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Tidskriftsartikel (refereegranskat)abstract
- A significant (similar to 1.8%) positive unit between the parameters of the crystal lattice is the reason of tetragonal distortion (a (aSyen)/a (aEuro-) a parts per thousand 1.04) and reduction in the volume of the unit cell of La(0.67)Ca(0.33)MnO(3) films (15 nm) quasicoherently grown on the (001) surface of a LaAlO(3) substrate. The films consist of single-crystal blocks with the lateral size of 30-50 nm. The atomically smooth LaAlO(3)-La(0.67)Ca(0.33)MnO(3) interphase boundary has no misfit dislocations. At T = 4.2 K, the transformation of nonferromagnetic phase inclusions into ferromagnetic ones in a constant magnetic field H is accompanied by a stable reduction in the electrical resistivity rho of manganite films with time, so that the curve rho(t) is well approximated by the relationship rho(t) similar to rho(1)(t - t (0))(1/2), (where t (0) is the time for establishment of the specified value (mu(0) H = 5 T) of the magnetic field and rho(1) is a coefficient independent of H). The magnetocrystalline anisotropy due to the elastic deformation of films by the substrate and stratification of electronic phases are the reasons of the distinct hysteresis in the dependences rho(mu(0) H, T 0 -> -5 T -> 0 -> 5 T. At T = 50 K and mu(0) H = 0.4 T, the magnetoresistance MR = 100% [rho(mu(0) H) - rho(mu(0) H = 0)]/rho(mu(0) H = 0) of LCMO films attains 150%.
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| 4. |
- Gunnarsson, Robert, 1972, et al.
(författare)
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Fabrication and characterisation of La0.67Sr0.33MnO3 submicron grain boundary junctions
- 2004
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Ingår i: Annalen der Physik (Leipzig). ; 13:1-2, s. 101-102
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Konferensbidrag (refereegranskat)abstract
- We have successfully fabricated LSMO grain boundary bicrystaljunctions with widths down to 200 nm. The grain boundaries aresymmetric with misorientation angles of 24degrees or 36.8degrees, and the microbridges are positioned across thosewith a precision better than 0.5 micro-meter. Grain boundary magnetoresistance is observed in the wider junctions but not in the most narrow junction.
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| 5. |
- Holmgren, Magnus, 1983-, et al.
(författare)
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Purification of hydrogen in aluminium recycling
- 2014
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Ingår i: Proceeding book of the 14th international foundrymen conference. - Sisak, Croatia : University of Zagreb Faculty of Metallurgy. - 9789537082178 ; , s. 17:1-17:8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Second to steel, aluminium is the most widely used metal and its applications are manifold. It is available in all forms; such is wire, bars, extrusions, power, forging and casting. One of the major characteristics of aluminium is that it is very well suited for recycling. Recycled aluminium is known as secondary aluminium, but maintains the same physical properties as primary aluminium. The Company XY is a cast house in the Nordic countries supplying aluminium cast products. Customers today are placing greater demands on the products strength and quality. An important quality parameter of aluminium is its purity from contaminants, where hydrogen is one of the major issues with impact on the strength of the final product. The hydrogen content has been measured by Density Index for two different types of alloys (EN AB-43400 and EN AB-46000), at specific locations, at different stages in the process and with different degassing methods. Density Index is a measure for measuring and comparing the samples with respect to the internal porosity. As the air contains moisture, along with the melt temperature, the solubility of hydrogen in the melt is affected. The project work has focused on reducing the hydrogen content and to improve the strength of the final product.
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