Affiliation:
1. Politehnica University of Bucharest, Materials Science and Engineering Faculty, Bucharest, Romania
Abstract
Previous experiments showed a specific distribution of Al, La, and Ca on the section of complex (Mn,X)S compounds, found as major nucleation sites for graphite flakes in low-S cast irons (< 0.03%S), and a possible contribution of La to improve their capacity to nucleate graphite, avoiding carbides formation. In the present work, standard thermal [cooling curves] investigations were undertaken to explore Ca and La-Ca bearing FeSi alloys inoculation effects [10 measurements for each inoculant], in 3.7 ? 3.8%CE and optimum S and Mn relationship [0.046 ? 0.056%S, (%Mn) x (%S) = 0.024 ? 0.029]. Representative temperatures on the cooling curves and under-cooling degrees referring to the meta-stable eutectic temperatures were determined and correlated with the chill [carbides/graphite formation sensitiveness], in different solidification conditions [cooling modulus, wedge shape castings, resin sand mould]. Supplementary addition of La to Cabearing inoculants had limited, but specific benefits in these cast irons: lower eutectic recalescence and maximum recalescence rate, higher GRF1 and lower GRF2 graphitizing factors, and lower value of the first derivative at the end of solidification. Consequently, it resulted in a premise for lower shrinkage sensitiveness and lower chill (carbides) sensitiveness, especially at the highest solidification cooling rate (thin wall castings).
Publisher
National Library of Serbia
Subject
Materials Chemistry,Metals and Alloys,Mechanics of Materials,Geotechnical Engineering and Engineering Geology
Cited by
1 articles.
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