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Eisengusswerkstoffe
Dokumenten-Nummer: 57824
Tagungsbeitrag
Heckmann, C. J.; Stets, W.; Wolf, G.
Publikationssprache: Englisch
Plate Fracture of Nodular Cast Iron
Plattenbruch bei Gusseisen mit Kugelgraphit
Plate fracture is a defective fracture structure in nodular cast iron that can be found especially in the transition area of
feeder, feeder neck and the cast part itself. It occurs rather spontaneously due to the fact that the exact reason for it is
still unknown. The microstructure of the casting in the area of plate fracture comprises aligned graphite nodules in
combination with a pronounced dendritic microstructure as characteristical features. A series of casting trials was
performed in which plate like samples were produced. It could be shown by means of metallographic investigation of
these samples in combination with the simulation of the solidification that specific local conditions during the
solidification are the metallurgical reasons for the appearance of plate fracture. These specific conditions were the local
temperature gradient and the velocity of the liquid/solid interface.
Institut für Gießereitechnik (IfG), Düsseldorf, DE
Erscheinungsjahr 2010
S. S.367-373
Seiten/Bilder/Tabellen/Quellen: 7S
Eisengusswerkstoffe
Dokumenten-Nummer: 57844
Tagungsbeitrag
Hirose, Masanori; Yamamoto, Kaoru; Miyahara, Hirofumi; Sakata, Kazunori; Ogi, Keisaku
Publikationssprache: Englisch
Abrasion Behavior of High Cr-V-Nb Cast Iron
Verhalten bei Abrasivverschleiß von hochlegiertem Cr-V-Nb-Gusseisen
A series of abrasion tests on high Cr-V-Nb cast irons revealed that the addition of MC type carbide formers, V and Nb,
remarkably enhances the abrasion resistance of high Cr cast iron, and the abrasion resistance becomes higher with the
increase in MC type carbides[1]. Therefore, hyper eutectic Fe-4.7%C-15%Cr-7%V-5%Nb-5%Mo alloy melt was poured into
30 kg and 1 kg sand mold castings to distribute different sizes of primary and eutectic carbides in hardenable matrix.
The abrasion test specimens cut from each casting were austenitized at 1323 K for 1h then cooled in air. These
specimens were tempered at 773 K for 1h followed by air cooling. The hardness of specimens was 1015-1018HV50.
The rubber wheel abrasion test, a typical 3 body type one, was performed on these quenched and tempered specimens
with 56-107, 107-150 and 297 micro m dia. silica grit. The testing load was 86.3 N and 172.5 N, and the rubber wheel
rotation speed was varied from 1 s(exp -1) to 4 s(exp -1). Though the higher testing load increases the wear loss, the
wear rate expressed by the wear volume/(testing load x wear distance) changes depending on the wear condition and
the microstructure. In case of 30 kg cast specimen, the silica grit preferentially attack and scrape off the matrix, and
the wear rate increases with the increase in the testing load. The fine carbides in 1 kg cast specimens effectively
protect the matrix from the attack of silica grit, and the wear rate decreases with increasing load which causes silica
grit blunt and fracture. However, fine carbides tend to be fractured by silica grit and diminish the protective effect.
Based on the worn surface structures, the abrasion mechanism is discussed comparing those of steel and eutectic
25%Cr cast iron.
Fukuoka Industrial Technology Center, Kitakyushu, JP; Kurume National College of Technology, JP; Kyushu University,
Fukuoka, JP; Fujikikosan, Kitakyushu, JP; Oita National College of Technology, JP
Erscheinungsjahr 2010
S. S.243-248
Seiten/Bilder/Tabellen/Quellen: 6S
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