Sulfidation/carburization resistance of several heat-resistant alloys at 900 C

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:352593

Harper, M A; Barnes, J E ^[1]

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1. Haynes International, Kokomo, IN (United States)

The results of high temperature sulfidation plus carburization testing on seven different commercial heat resistant alloys are reported in this paper. The test environment consisted of a H{sub 2}-25vol%CH{sub 4}-14.8N{sub 2}-4CO-0.6H{sub 2}S gas at 1650 F (9OO C) and the time of exposure was 500 hours. Relatively thick, mixed sulfide scales were formed on all of the alloys tested. Also, internal carburization occurred within all of the alloys. The use of x-ray diffraction allowed the phases constituting the scales to be identified, and these phases were in agreement with previous work published on the testing of various alloys in high temperature low oxygen activity, high sulfur and carbon activity atmospheres. Using metal loss (i.e. the reduction in sample thickness) plus internal attack (internal sulfidation plus internal carburization) as a performance criterion, an alloy with a nominal composition of Ni-29wt%Co-28Cr-2.75Si performed the best, showing 28 mils (0.71 mm) of attack, and an alloy with a nominal composition of Fe-20wt%Ni-25Cr performed the worst, being totally consumed by the test (>125 mils/3.18 mm of attack). The sulfidation plus carburization resistance of the Ni-Co-Cr-Si alloy is attributed to its high chromium plus silicon content, both of which are known to be beneficial in sulfidizing and carburizing environments, and its low iron/high nickel content, which results in a low solubility and diffusivity of carbon in the matrix.

• OSTI ID: 352593
• Report Number(s): CONF-980316--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
36 MATERIALS SCIENCE
CARBURIZATION
CHEMICAL COMPOSITION
CHROMIUM-NICKEL STEELS
COAL GASIFICATION
CORROSION PRODUCTS
HEAT RESISTING ALLOYS
NICKEL BASE ALLOYS
SCALING
SULFIDATION