• norsk
    • English
  • English 
    • norsk
    • English
  • Login
View Item 
  •   Home
  • Fakultet for naturvitenskap (NV)
  • Institutt for materialteknologi
  • View Item
  •   Home
  • Fakultet for naturvitenskap (NV)
  • Institutt for materialteknologi
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Hydrogen permeation in different microstructures of 66SiMnCrMo6-6-4 steel

Vågenes, Christian
Master thesis
Thumbnail
View/Open
no.ntnu:inspera:140608939:35244697.pdf (3.809Mb)
no.ntnu:inspera:140608939:35244697.zip (321.0Mb)
URI
https://hdl.handle.net/11250/3096514
Date
2023
Metadata
Show full item record
Collections
  • Institutt for materialteknologi [2408]
Abstract
Diffusiviteten til hydrogen i stål er bestemmes av ulike mekanismer som forårsaker sprøhet. Avhengig av mikrostrukturen kan hydrogensprøhet være forårsaket av mange typer mekanismer, som derfor gjør det utfordrende å forutsi nøyaktig hvordan hydrogen introdusert i bulkmaterialet oppfører seg. Diffusjonseksperimenter av mikrostrukturene B240, B280, QT440 og Q ble utført, som alle er av det samme 66SiMnCrMo6-6-4-stålet. Hver prøve ble testet tre ganger for å produsere tre forskjellige transienter. Disse transientene ble deretter sammenlignet og steady-state normalisert for å undersøke hydrogenfellene ("hydrogen traps") i alle mikrostrukturene. Resultatene som ble oppnådd viste at QT440 hadde en noe høyere hydrogendiffusivitet og stabil fluks i forhold til de andre mikrostrukturene i det samme stålet, og det antas at grunnen er lavere austenittinnhold. Sammenlignet med andre stål var hydrogenpermeabiliteten fortsatt betydelig lavere enn for gjennomsnittlige stål, men ved å bruke formelen til Boellinghaus (Boellinghaus et al., Welding in the World, vol. 35, 1995, s. 149) ble det fastslått at resultatene fortsatt er troverdige, siden diffusjonskonstanten er høyere enn den minste logiske diffusjonskoeffisienten i stål. Irreversible og reversible feller ("traps") ble undersøkt. Alle mikrostrukturene viste tegn til reversible feller ("traps"), men få eller ingen irreversible feller ("traps"). Dermed konkluderes det med at legeringen generelt sett er svært gjennomtrengningsbestandig.
 
The diffusivity of hydrogen in steel is dictated by various mechanisms which causes brittleness. Depending on the microstructure, hydrogen embrittlement can be caused by a plethora of mechanisms, which therefore makes it challenging to accurately predict the behaviour of hydrogen introduced to the bulk material. Diffusion experiments of B240, B280, QT440 and Q microstructures of the 66SiMnCrMo6-6-4 steel were performed, and each sample was tested three times to produce three different transients. These transients were then compared and steady-state normalized to research the trapping abilities of all microstructures. The results which were obtained showed that QT440 had a slightly higher hydrogen diffusivity and steady state flux than the other microstructures of the same steel, and its lower content of austenite is believed to be the reason. Compared to other steels the hydrogen permeability was still significantly lower than average, but

by using the formula of Boellinghaus(Boellinghaus et al., Welding in the World, vol. 35, 1995, p. 149) it was found that the findings are still plausible, as the diffusion constant is higher than the minimum logical diffusion coefficient in steel. Irreversible and reversible trapping was looked into, and while there were little or no irreversible traps seen, all microstructures did show signs of reversible trapping. Therefore it is concluded that the alloy is generally very permeation resistant.
 
Publisher
NTNU

Contact Us | Send Feedback

Privacy policy
DSpace software copyright © 2002-2019  DuraSpace

Service from  Unit
 

 

Browse

ArchiveCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsDocument TypesJournalsThis CollectionBy Issue DateAuthorsTitlesSubjectsDocument TypesJournals

My Account

Login

Statistics

View Usage Statistics

Contact Us | Send Feedback

Privacy policy
DSpace software copyright © 2002-2019  DuraSpace

Service from  Unit