ISSN:
1573-4889
Keywords:
catastrophic carburization
;
materials disintegration
;
carbon deposition
;
low- and high-alloy steels
;
iron, nickel and iron-nickel alloys
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Metal dusting is a catastrophic carburization of steels which leads to disintegration of the material to a mixture of powdery carbon and metal particles leaving pits and grooves. The phenomenon was simulated by carburization of low-and high-alloy steels in CO-H2-H2O mixtures at carbon activities 〉 1 in the temperature range 600–700°C. The occurance of an unstable carbide M3C (M=Fe, Ni), as an intermediate in metal dusting, was proven—the reaction sequence involves over saturation of the metal matrix with carbon, M3C formation at the surface, subsequent decomposition of the M3C layer M3C→3 M+ C, leading to carbon with interspersed metal particles which act as catalysts for additional carbon deposition from the gas atmosphere. With increasing Ni content in Fe-Ni alloys, typical metal dusting is suppressed, but another mode of deterioration was observed, involving graphite growth on the grain boundaries. The high-alloy, chromia-forming alloys showed metal dusting only when chromia formation was suppressed by electropolishing the materials.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00664665
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