Effects of tertiary elements on the critical solidification rate of the flake-undercooled graphite transition of Fe-C alloys

摘要

This paper reports an investigation about the effects of 0.004-0.108 mass%S, 0.068-1.10 mass%Si, 0.047-0.177 mass% Ti, 0.035-0.078 mass% Zr, and 0.018-0.042 mass% S and 0.047-0.l4mass%Mn on the critical solidification rate of theflake-under-cooled graphite, R{sub}c, and inter-graphite spacingλ of gray cast iron during an unidirectional solidification method.The specimens had a mass of 150 g, a diameter of 24 mm, and a length of 60 mm. The temperature gradient at the solid-liquid interface was 18-21 K/cm. The experimental equations for the relation betweenλ and R was obtained using regression analysis. As Rbecomes larger, λ decreases and the transition from flake to under-cooled graphite occurs R{sub}c. The R{sub}c value varied with the elements added. The effects of S and Si intricately changed depending on their amount. Ti and Zr decreased R{sub}c. Mnhas no influence. The temperature gradient at the solid-liquid interface and the amount of surface-active elements also influence R{sub}c.