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Magnesium Melt Protection

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Abstract:

Mg especially in the molten state is well known for its high affinity to O2. When O2 content of the atmosphere is larger than 4%, molten Mg will burn! To avoid this, melt protection is necessary. At present mostly SF6 is used during primary production and processing of Mg and its alloys. Unfortunately SF6 is a very potent greenhouse gas that is > 23,000 times more effective than CO2. This also affects life cycle considerations e.g. for the use of Mg alloys in transportation. However, other protective gases like SO2 or fluorinated hydrocarbons like HFC134a, Novec 612, or AMCover (=HFC134a) have been suggested to replace SF6. Additionally fluxes mixed from different salts may be used again as well to protect molten Mg. But fluxes and feasible replacements of SF6 have also disadvantages. Moreover SF6 and other fluorinated hydrocarbons are under discussion especially in Europe. There is an existing EU legislation that will ban SF6 from 2018 and there are similar discussions regarding all other fluorinated hydrocarbons. Due to this, new innovative ways have to be found or old methods have to be renewed to allow Mg industries further safe processing of molten magnesium. This contribution will report the state of the art in protecting molten Mg and alternatives to the use of SF6.

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Periodical:

Materials Science Forum (Volumes 828-829)

Pages:

78-81

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.828-829.78

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Online since:

August 2015

Authors:

Norbert Hort*, Börn Wiese, Hajo Dieringa, Karl Ulrich Kainer

Keywords:

Fluorinated Hydrocarbons, Flux, Melt Protection, SF6, SO2

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© 2015 Trans Tech Publications Ltd. All Rights Reserved

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