leometwu的部落格

Macro photos for this FC 200
The one in the middle is 5  mm in thickness.
White area is mostly Ferritic while dark area is Pearlitic.
Chill effect of green sand mold causes  undercooling of iron melt
and  produces D-type graphite which favors the formation of Ferrite on the edge.
As the degree of undercooling subsides inward, A-type graphite
makes its appearance, accompanied by Pearlite

中: 肉厚5 mm. 上下表面各有~ 1 mm的白亮區是全肥粒鉄. 內部~ 3mm全波來鉄. 為何如此? Why?

Below: micro metallographes of this FC 200.