研究論文
1カップ熱分析による球状黒鉛鋳鉄の黒鉛粒数とひけ性の判定
2017 年 89 巻 6 号 p. 332-337
詳細
2017 年 89 巻 6 号 p. 332-337
Three cup thermal analysis is a good method for predicting chill depth, tensile strength, and graphite type in gray cast iron. However, it cannot be used for ductile cast iron due to several reasons. For this reason, we have developed a method for investigating the graphite eutectic temperature (hereafter TEG) and cementite eutectic temperature (hereafter TEC) in ductile cast iron, from the chemical composition of molten metal as follows ;
TEG ＝ 1149.1 (℃) ＋ 4.7Si% － 4.0Mn% － 44P% ＋ 2.7Cu% ＋ 1.0Ni% ＋ 1.8Co% ＋ 13.9Al% － 17.7 Mo% － 10.5Cr% － 9.3Sn% － 5.2Sb% － 6.1W% － 3.7Nb% － 14.8V% － 80.3B%
TEC ＝ 1142.6 (℃) － 11.6Si% － 0.75Mn% － 46.2P% － 1.4Cu% － 1.1Ni% － 0.7Co% － 1.8Al% － 14.5Mo% ＋ 5.9Cr% － 6.0Sn% － 5.1Sb% － 2.8W% ＋ 0Nb% ＋ 3.3V% － 26.0B%
Using the cooling curve of 1 cup and the above equations, we calculated eutectic graphitization ability (hereafter EGA). We investigated if this one cup thermal analysis can be used to predict the quality of molten metal (graphite nodule count and shrinkage tendency) correctly even in ductile cast iron before it is poured.
The graphite nodule count (N) of CE cup T.P. is determined by EGA (＝ ΔT1 × 100/ΔTE) as follows : N ＝ 6.13 × (ΔT1 × 100/ΔTE) － 126 In addition, when EGA exceeds 90%, the shrinkage tendency parameter (θ) becomes low near 55° which is that of gray cast iron. Consequently, one cup thermal analysis is a good system for predicting the quality of molten metal (graphite nodule count and shrinkage tendency) correctly in ductile cast iron before pouring.
