Effects of alloying elements on the microstructure and fatigue properties of cast iron for internal combustion engine exhaust manifolds

dc.contributor.advisor Scott Chumbley
dc.contributor.author Eisenmann, David
dc.contributor.author Eisenmann, David
dc.contributor.department Materials Science and Engineering
dc.date 2018-08-11T07:37:19.000
dc.date.accessioned 2020-06-30T02:59:18Z
dc.date.available 2020-06-30T02:59:18Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2015
dc.date.embargo 2001-01-01
dc.date.issued 2015-01-01
dc.description.abstract <p>In the design of exhaust manifolds for internal combustion engines the materials used must exhibit resistance to corrosion at high temperatures while maintaining a stable microstructure. Cast iron has been used for manifolds for many years by auto manufacturers due to a combination of suitable mechanical properties, low cost, and ease of casting. Over time cast iron is susceptible to microstructural changes, corrosion, and oxidation which can result in failure due to fatigue. This thesis seeks to answer the question: “Can observed microstructural changes and measured high temperature fatigue life in cast iron alloys be used to develop a predictive model for fatigue life?” the importance of this question lies in the fact that there is little data for the behavior of cast iron alloys at high temperature. For this study two different types of cast iron, 50HS and HSM will be examined. Of particular concern for the high Si+C cast irons (and Mo in the case of the HSM cast iron) are subsurface microstructural changes that result due to heat treatment including (1) decarburization, (2) ferrite formation, (3) graphitization, (4) internal oxidation of the Si, (5) high temperature fatigue resistance, and (6) creep potential. Initial results obtained include microstructure examination after being exposed to high temperatures, grain size, nodule size, and hardness measurements. The initial examinations concluded that both cast irons performed fairly similarly, although the microstructure of the HSM samples did show slightly better resistance to high temperature as compared to that of the 50HS. Follow on work involved high temperature fatigue testing of these two materials in order to better determine if the newer alloy, HSM is a better choice for exhaust manifolds. Correlations between fatigue performance and microstructure were made and discussed, with the results examined in light of current and proposed models for predicting fatigue performance based on computational methods, to see if any suitable models exist that might be used to assist in designing with these cast alloys.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/14805/
dc.identifier.articleid 5812
dc.identifier.contextkey 8330800
dc.identifier.doi https://doi.org/10.31274/etd-180810-4391
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/14805
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/28990
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/14805/Eisenmann_iastate_0097E_15307.pdf|||Fri Jan 14 20:27:31 UTC 2022
dc.subject.disciplines Materials Science and Engineering
dc.subject.disciplines Mechanics of Materials
dc.subject.keywords Materials Science and Engineering
dc.subject.keywords cast iron
dc.subject.keywords fatigue
dc.subject.keywords high temperature
dc.subject.keywords three point bend
dc.title Effects of alloying elements on the microstructure and fatigue properties of cast iron for internal combustion engine exhaust manifolds
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isAuthorOfPublication 2aac4aee-69d0-42ea-a1ed-e13dac43a144
relation.isOrgUnitOfPublication bf9f7e3e-25bd-44d3-b49c-ed98372dee5e
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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