Abstract
Stress relaxation cracking failure is widely reported in the materials used for thermal power plants, which seriously affected the safety of thermal power units under long-term service. In our study, the influence of intergranular precipitation behavior on the stress relaxation cracking susceptibility of Super304H austenitic stainless steel weld metal was investigated based on the pre-compressed CT technique. The 45° misorientation grain boundary has the lowest critical interfacial nucleation energy, followed by the grain boundaries away from the 45° misorientation. As a result, the coarse intergranular M23C6 carbides were more prone to precipitate at 45° misorientation grain boundary, which led to the lowest resistance to stress relaxation cracking susceptibility at 35 to 45° grain boundary. Further analysis indicated that intergranular cavities were easily initiated at the non-coherent M23C6/γ interface. Since the non-coherent interface with a low Cr concentration zone and high specific interfacial energy had a lower strength, the lattice distortion at the non-coherent interface could lead to higher strain concentration.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.