ISSN:
1573-4889
Keywords:
CYCLIC OXIDATION
;
CHROMIA-FORMER
;
INTERNAL OXIDATION
;
SCALE SPALLATION
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Long-term, cyclic-oxidation testing in still airfor about 2 years (720 days) at 982°C and 1 year(360 days) at 1093, 1149, and 1204°C has beenconducted on the commercial, high-temperaturechromia-forming HR-120®, HR160®, and 230® alloys(all trademarks of Haynes International, Inc.). Eachthermal cycle consisted of 30 days at temperaturefollowed by about 4 hr at ambient. The resultsdemonstrated the significant effects of alloy composition on long-term,cyclic-oxidation resistance. Each of the alloysexhibited scale spallation; however, the manner by whichspallation occurred varied between the alloys. The 230 alloy, which contains 0.02 wt.% La, exhibitedpartial scale spallation, thus allowing for the easierformation of a protective or semiprotectiveCr2O3-rich scale during subsequentoxidation. The HR-160 alloy exhibited complete spallation owinglargely to its relatively high silicon content (2.75wt.%). However, the silicon was also beneficial inpromoting protective or semiprotective scale formationwhen the exposed alloy was subsequently oxidized.The HR-120 alloy showed the poorest cyclic-oxidationresistance, due in part to poor scale adhesion and thetendency of the iron in this alloy (33 wt.%) toeventually oxidize and result in the formation of aless-protective scale. All of the alloys underwentinternal attack in the form of internal oxidation andvoid formation. In most cases, the extent of internalattack was significantly greater than that of metalloss.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018874206733
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