METHOD FOR MELTING ALUMINUM-MAGNESIUM BASED ALLOY SCRAP

摘要

PURPOSE: To regenerate Al-Mg based alloys having high cleanliness by specifying a heating up rate until a specific melting temp. is attained and specifying the holding time at this melting temp. CONSTITUTION: The melting temp. is set at <=750 deg.C in the case raw materials contg. Al-Mg based alloy scrap are melted in an amt. atmosphere. The holding time thereof is set at <=4 hours. The forming amt. of the MgAl2 O4 increases if the temp. and time described above are set at >=750 deg.C and >=4 hours. The heating up rate until the melting temp. is attained is set at >=150 deg.C/hour. Then, the formation of the MgO at the time of heating up is suppressed and the amt. of the MgAl2 O4 at the time of the heating up is remarkably suppressed and the increase in the amt. of the MgAl2 O4 is suppressed even in the holding process at the melting temp. Consequently the content of the MgAl2 O4 eventually decreases remarkably. As a result, the amt. of oxide based inclusions is decreased.