Light optical and scanning electron microscopy techniques were used fo
r high-carbon ferrochromium microstructural analysis. Different micros
tructures were observed for industrially and laboratory-produced ferro
alloys. Primary carbides of M(7)C(3) with chromium ferrite were found
in the industrially produced, slowly solidified, and cooled ferroalloy
, while primary M(7)C(3) carbides accompanied a eutectic mixture of M(
7)C(3) carbides and chromium ferrite in the laboratory-melted and in t
he water-solidified and water-cooled materials. Different microstructu
ral arrangements are directly related to the friability properties of
this material. which characterizes its resistance to abrasion on handl
ing and impact. In ferrochromium upgraded by carbon content reduction,
the eutectic M(7)C(3) hexagonal carbides are partly replaced by M(23)
C(6) dendritic carbides. The presence of dendritic carbides in the fer
rochromium eutectic microstructure can be interpreted as a proof of a
lower carbon content, raising the commercial value of the ferroalloy.
The hexagonal M(7)C(3) carbides exhibited a central hollow along the l
ongitudinal axis, and on metallographic samples they looked like screw
nuts. A model of the solidification mechanism for such crystals is pr
oposed. (C) Elsevier Science Inc., 1996.