Livarski vestnik 54 / 2007 Nr. 4
Ingo Siller, H. Schweiger, D. Caliskanoglu:
Trends in Vacuum-Arc-Remelted Tool Steel Design for Die Casting Applications
Davor Špoljarič, B. Holleis, Bernard Grobelnik:
Application of Oxygen for Recycling of Metals
Petrič Mitja, Mrvar Primož, Medved Jožef:
Modification of AlSi10Mg Alloys and the in Situ Control of Nucleation Potential as a Function of Cooling Rate
Ingo Siller, H. Schweiger, D. Caliskanoglu
for Die Casting Applications
For economic reasons casting dies are subjected to continuously increasing loading conditions during die casting processes. Therefore the time of either change or repair of the die is determined by a catastrophic failure of the die or the high costs of machining the cast parts. In addition to those mentioned above, the main causes of failure in die casting tools are thermal fatigue cracks, stress cracks, damage due to erosion and chemical attacks. Hot work tool steel grades which have a homogeneous microstructure, a high cleanliness and consequently excellent mechanical properties are in great demand for complex load situations and also to increase the die life time. These characteristics can be achieved using a vacuum-arc-remelting process, which results in a remarkable increase in the toughness of the tool steel material and further an improvement of die life. In this paper we will compare the thermomechanical and thermophysical material properties of an electro-slag remelted hot work tool steel material (DIN 1.2343) with the new vacuum-arc remelted grade. The effects of the different manufacturing routes on the die life are summarised in examples from die casting industry.
Key words: Hot Work Tool Steel, Vacuum Arc Remelting, Toughness, Cleanliness, Homogeneity
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Davor Špoljarič, B. Holleis, Bernard Grobelnik
The combustion systems used in the secondary production of metals often feature the use of tonnage oxygen directly or oxygen enrichment of air in the furnace body. This is used for e.g. to increase the capacity or melting rate of particular furnaces and to provide discrete oxygen rich areas in a furnace to allow complete combustion separately from a reducing zone. This article analyses the possibilities and the advantages of oxygen application in different furnace types (rotary, shaft, reverberatory, EAF) for secondary metal production.
Key words: melting process, use of oxygen
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Petrič Mitja, Mrvar Primož, Medved Jožef
of nucleation potential as a function of cooling rate
The solidification of the AlSi10Mg aluminium cast alloys has been investigated. Examinations have been made by the in situ thermal analyses, simultaneous thermal analyses (STA) and metallographic analyses. The examined AlSi10Mg alloy has been grain refined and modified. The undercooling and recalescence of primary and eutectic crystallization have been analyzed by cooling curves at different cooling rates, and a relation with the size of the aAl primary crystals and the bSi eutectic phase from the (aAl + bSi) eutectic has been established.