Livarski vestnik 63/2016 nr. 2

Milan Topić1, Karin Tschiggerl1, Mathias Rauter2, Klaus Doschek2, Hubert Biedermann1, Harald Raupenstrauch2 , ¹Chair of Economic and Business Management,²Chair of Thermal Processing Technology , Montanuniversität Leoben, Austria

FOUNDRY PRODUCTS AND THEIR ADDED VALUE IN THE LIFE CYCLE ASSESSMENTS

Zdenka Zovko Brodarac¹, Josip Kalinić², Vanja Šuica^1*, ¹University of Zagreb, Faculty of Metallurgy, Sisak, Croatia, ^1* student at University of Zagreb, Faculty of Metallurgy, Sisak, Croatia, ² Jajce Alloy Wheels Ltd, Jajce, Bosnia and Herzegovina

SOLIDIFICATION SEQUENCE OF ALSI11 ALLOY

M. Vončina¹, V. Tubin², P. Mrvar¹, J. Medved¹, ¹Faculty for Natural Sciences and Engineering, Department of Materials and Metallurgy, ²Talum, Tovarna aluminija d.d.

BONDING OF AA1170 AND AA6060 ALLOYS

FOUNDRY PRODUCTS AND THEIR ADDED VALUE IN THE LIFE CYCLE ASSESSMENTS

Abstract

Rising energy costs, new environmental regulations and concerns about energy security are causing industries to conduct efforts to reduce energy consumption and increase energy efficiency. The international and the national legislator are developing different legal framework conditions to support the implementation of energy saving strategies. A recent contribution to this issue is the commencement of the European Energy Efficiency Directive, which at Austrian national level finds its application in the form of the energy efficiency law. Particularly the energy-intensive industries (e.g. foundry industry) are faced to reduce their energyconsumption, to increase energy efficiency and improve their environmental performance. In order to fulfill the plans and targets given by the legislator's an integrated approach on energy efficiency measures has to be used with special focus on the technical, economic and ecologic methods and assessments.

For the investigation of the efficiency potential in the foundry industry, the modular- based, multilevel approach was developed. The model/approach was generated through collaboration between the experience and know-how of the Austrian Economic Chamber - Association of Austrian foundry industry and their commercial partners, and science, i.e. the Montanuniversitaet Leoben and the Austrian Foundry Research Institute (ÖGI). The approach enables the derivation of actual energy consumption of processes and corresponding manufactured products, and leads therefore to a better understanding of cost generation. Moreover, the methodology identifies energy efficiency potentials and merges them to a model based approach for the planning, evaluation and optimization of energy consumption in the foundry industry. These measures can show positive effects on the phases of the product lifecycle.

Aside the technical and economic measures, the life cycle assessment (LCA) represents an important part of the model development. LCA provides a method of assessing the environmental impacts of a product material and energy flows across the whole supply chain, from raw material extraction to end of life recycling or disposal. The method is based on ISO Norm 14040ff which describes the principles and framework for life cycle assessment (LCA) including: definition of the goal and scope of the LCA, the life cycle inventory analysis (LCI), the life cycle impact assessment (LCIA) and the life cycle interpretation.

Regarding the aims of the project and research interests the model focuses on three impact indicators relevant for the foundry industry: (1) Global Warming Potential (GWP), (2) Cumulative Energy Demand (CED) and (3) Cumulative Material Demand (CMD). The benefits for the foundry industry from life cycle assessment include the identification of improvement potential of environmental characteristics of products, the purchase of information for strategic planning, priority setting, product and process development, as well as arguments for the marketing of products.

SOLIDIFICATION SEQUENCE OF ALSI11 ALLOY

Abstract

The automotive industry is forced to apply advanced materials and technologies in order to overcome the mutual competition, but also for compliance withenvironmental regulations requiring reduction of emissions, and fuel consumption. One of main component for achieving this goal is weight saving by downsizing of components using advanced materials and production technologies.

The widest production of automotive aluminium component refers to wheels produced by low pressure die casting. Complex geometry of thin wall wheel casting indicates application of AlSi11 alloy (EN AC 44000). An AlSi11 alloy (EN AC 44000) belongs to the group of “eutectic alloys” and is characterized with relatively low melting point and narrow solidification interval which both brought to the uniformly distributed eutectic microstructure indicating superior mechanical and technological properties. This is the reason for this alloy to be widely used for high and low pressure die casting production. Silicon is one of the most important alloying elements which comprehend to good castability of aluminium alloys. Addition of silicon improves resistance to hot cracks and feeding capability. Synergy of influenced alloying and trace elements effect comprehend to different intermetallic phase evolution.

The content of secondary alloying elements (Mg, Cu) and trace elements (Fe, Mn, Cr, Zn) was minor in investigated AlSi11 alloy. Also thin wall casting geometry using low pressure die casting technology ensures rapid cooling with minimal available time for significant number of intermetallic phases development.

Metallographic analysis resulted in following microstructural constituents: primary aluminium α_Al, main eutectic α_Al + β_Si, high temperature iron phase Al₅FeSi, intermetallic phases in form of secondary eutectic Mg₂Si and Al₈FeMg₃Si₆.

Correlation of established microstructural constituents with thermodynamic modelling and differential scanning calorimetry indicates exact solidification sequence for this particular chemical composition.

M. Vončina¹, V. Tubin², P. Mrvar¹, J. Medved¹, ¹Faculty for Natural Sciences and Engineering, Department of Materials and Metallurgy, ²Talum, Tovarna aluminija d.d.

BONDING OF AA1170 AND AA6060 ALLOYS

Abstract

The interaction of the two materials based on aluminium for special conditions, such as elevated temperature and pressure, speeds up the bonding in the solid. Due to the elevated temperature at the interface, the process of diffusion occurs. The so-called "diffusion bonding" is carried out at high temperatures, of about 50-70 % of the melting temperature of the base material. Before bonding the solid surface must be properly cleaned. All the impurities (oxides, dust, moisture ...), which are present on the surface of metals must be removed.

The interaction between two identical (AA1170) and two different (AA1170 and AA6060) materials has been investigated. Tests were carried out by thermomechanical simulator of metallurgical states Gleeble 1500D at different temperatures (400 ̶ 600 °C), forces (40 ̶ 80 kN) and various tool constructions. Compressed samples were examined macroscopically. Furthermore, the microstructure was analyzed by optical microscope and the bond was tested using DSC analysis. The microhardness of the bonds was analysed. The best results show the bond that was compressed with the construction of the tool with negative rib at temperature of 450 °C and force of 35 kN, which was cleaned with cleaning media Nubadur 152 (S).