Assessing Melt Quality in 6060 Aluminum Castings Using Bifilm and Density Indexes
Bilgehan Tunca *
R&D Department, Sistem Alüminyum San. ve Tic. A.Ş., Turkey.
Burak Ince
R&D Department, Sistem Alüminyum San. ve Tic. A.Ş., Turkey.
Dilek Deniz
R&D Department, Sistem Alüminyum San. ve Tic. A.Ş., Turkey.
*Author to whom correspondence should be addressed.
Abstract
This study evaluates the influence of refining processes on the liquid metal quality of 6060 aluminum alloy castings, comparing two batches (Cast-1 and Cast-2) with varying degassing durations and filtration conditions. Liquid metal quality was assessed using the Reduced Pressure Test (RPT), measuring density index (DI), bifilm index (BI), hydrogen level, and microstructural properties. Cast-1 exhibited ineffective refining, with BI increasing from 127 mm to 155 mm post-fluxing, a high DI (6.9–9.75%), and a coarse microstructure (120 µm grain size, 76% homogeneity) with abundant defects. In contrast, Cast-2 demonstrated higher quality, with BI decreasing from 119 mm to 10.4 mm, DI dropping to 2.32%, and a refined microstructure (111 µm grain size, 80% homogeneity) due to optimized refining and smaller-pored filtration. The results highlight bifilms as key porosity initiators and underscore the importance of tailored refining strategies for enhancing casting quality, offering practical insights for industrial applications.
Keywords: Aluminum alloy, porosity, melt quality, bifilm index, refining process