ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
In this study, stellite 6 alloy was overlaid on spheroidal graphite (SG) cast irons with various carbon contents(1.5wt%~3.8wt%) and a fixed silicon content (approximately 2.5wt%) using the plasma transferred arc (PTA) process atdifferent overlaying current (140A~220A) while the travel speed of the PTA torch was maintained constant. Resultsindicated that the solidification structures of the stellite 6 overlayers were dendritic and had a large amount ofinterdendritic precipitates (M7C3 and M23C6 carbide) after the satellite 6 alloy had been overlaid on SG cast irons withdifferent carbon contents (1.5wt%~3.8wt%) at a low overlaying current (I=140A). The partially melted zones of thesubstrates below the carbide-containing interfacial layers consisted of eutectic carbides (ledeburites) and fine pearlites.The amount of the carbide-containing interfacial layers and ledeburites increased following the increase in theoverlaying current. The results of the tearing test reported that the occurrence of the carbide-containing interfacial layerswas detrimental to the bonding strength between the overlayers and the substrates. The metallography of the fracturedarea of the tearing specimens after the bonding strength test revealed that fractures always occurred at thecarbide-containing interfacial areas. On the other hand, the overlayers were rich in iron content when the overlayingcurrents were high (I=190A and 220A). Owing to the dilution effect, the matrices of the overlayers were α-Fe withlamellar M7C3 carbides. The results of the tearing test indicated that the bonding strength of the overlaid specimens wasrelatively low, and fractures always occurred in these highly diluted overlayers
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.345-346.505.pdf
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