Abstract
The relation between chromia scale spallation during oxidation or cooling down of ferritic stainless steels is generally discussed in terms of mechanical stresses induced by volume changes or differential thermal expansion. In the present paper, growth and thermal stress measurements in scales grown on different ferritic steel grades have shown that the main stress accumulation occurs during isothermal scale growth and that thermal stresses are of minor importance. However, when spallation occurs, it is always during cooling down. Steel-oxide interface undulation seems to play a major role at this stage, thus relating spallation to the metal mechanical properties, thickness and surface preparation. A major influence on spallation of the minor stabilizing elements of the steels was observed which could not be related to any difference in stress state. Therefore, an original inverted blister test was developed to derive quantitative values of the metal-oxide adhesion energy. These values clearly confirmed that this parameter was influenced by scale thickness and by minor additions, titanium greatly increasing adhesion whereas niobium decreased it.
Highlights
Ferritic stainless steels can be used in high temperature situations where mechanical solicitations are not too severe
This paper presents quantitative measurements of growth and thermal stresses and of oxide-substrate adhesion energy on several ferritic stainless steel grades and discusses their relation to scale spallation
Spallation of oxide scales grown on ferritic stainless steels depends on many parameters, among which are oxide thickness and steel minor additions, and metal thickness and nature of the oxidising atmosphere (O2 or H2O);
Summary
Ferritic stainless steels can be used in high temperature situations where mechanical solicitations are not too severe They present the advantage over the austenitic grades to faster passivate and reheal due to the high chromium diffusivity in the non compact bcc structure. Materials Research couplings) allows to reduce weight compared to the use of thick cast iron or carbon steel parts. Their performances may be increased, for example by retarding, reducing or suppressing scale spallation under cyclic conditions. This paper presents quantitative measurements of growth and thermal stresses and of oxide-substrate adhesion energy on several ferritic stainless steel grades and discusses their relation to scale spallation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
