Cost Effective and Robust Stainless Steel in Exhaust Environments for EGR systems
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Exhaust Gas Recirculation, EGR, is a system for reduction of environmental unfriendly emissions, especially NOX, for heavy duty engines. During recirculation the exhaust gases are cooled in the EGR coolers and the decrease in exhaust temperature results in formation of a corrosive condensate. The materials of the components of the EGR system thus need to be corrosion resistant.
The aim of this thesis was evaluate the stress corrosion cracking resistance on austenitic and duplex stainless steels. A cost analysis in regard to choice of material and manufacturing methods for the EGR cooler component has also been performed.
Two different materials were tested, austenitic stainless steel grade 1.4404 and one duplex stainless steel grade 1.4462. The method used was slow strain rate testing using an environmental chamber containing a synthetic condensate.
The results shows that the austenitic stainless steel grade 1.4404 is sensitive to pitting corrosion following stress corrosion cracking at chloride concentrations equal to or above 0.33 wt% in the exhaust condensate. The duplex stainless steel grade 1.4462 did not show any signs of corrosion and is therefore immune to stress corrosion cracking for the corresponding environment.
Place, publisher, year, edition, pages
stress corrosion cracking, EGR-system, duplex, austenitic, stainless steel
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-124779OAI: oai:DiVA.org:kth-124779DiVA: diva2:638552
Subject / course
Materials Science and Engineering
Master of Science - Engineering Materials Science
Odqvist, Joakim, Bitr. universitetslektor