Fatigue testing of scratched flapper valve steel
Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesisAlternative title
Utmattningsprovning av repat ventilstål (Swedish)
A flapper valve is made from a hardened and tempered high strength strip steel which opens and shuts as it is subjected to very high cyclic loads. Steel strip of which flapper valves are made from can encounter a surface defect which are anticipated to influence fatigue life negatively. In this study, the influence of surface scratches on fatigue life of flapper valve strip was investigated. The analysis was carried out by using thirty samples that were blanked out of eight different steel strips in the transverse direction. Of these samples, fifteen of them had scratches on the surface and fifteen did not, all these samples were fatigue tested by constant amplitude method. An S-N curve was plotted based upon the values and results from the fatigue test, considering the curve as the nerve center in relation with fractrographic studies using the Scanning electron microscope. Therefore this master thesis work aims to explain the influence of scratches on fatigue life of flapper valve strip and suggest future improvements based on the findings.
Place, publisher, year, edition, pages
2014. , 52 p.
Karlstad University Studies, ISSN 1403-8099 ; 1403-8099
flapper valve steel, fatigue testing, fatigue life measurements and comparison, stair case method, fatigue fractures
IdentifiersURN: urn:nbn:se:kau:diva-31704OAI: oai:DiVA.org:kau-31704DiVA: diva2:705114
Subject / course
Materials Engineering, Master of Science
Master of Science in Engineering, Degree Programme in Mechanical Engineering, specialisation in Materials Engineering (120 ECTS credits)
2012-10-06, KARLSTAD UNIVERSITY, SE-651 88 Karlstad, Sweden, Karlstad, 13:30 (English)
Krakhmalev, Pavel, Professor of Materials ScienceBurman, Christer, Professor of Materials Science
Bergström, Jens, Professor- Materials Engineering