Abstract
Casting of stainless steels is a promising and cost saving way of directly producing large and complex structures, such a shield modules or divertors for the ITER. In the present work, a series of modified high-nitrogen cast stainless steels has been developed and characterized. The steels, based on the cast equivalent of the composition of 316 stainless steel, have increased N (0.14–0.36%) and Mn (2–5.1%) content; copper was added to one of the heats. Mechanical tests were conducted with non-irradiated and 0.7 dpa neutron irradiated specimens. It was established that alloying by nitrogen significantly improves the yield stress of non-irradiated steels and the deformation hardening rate. Manganese tended to decrease yield stress but increased radiation hardening. The role of copper on mechanical properties was negligibly small. Analysis of structure was conducted using SEM-EDS and the nature and compositions of the second phases and inclusions were analyzed in detail. No ferrite formation or significant precipitation were observed in the modified steels. It was shown that the modified steels, compared to reference material (commercial cast 316L steel), had better strength level, exhibit significantly reduced elemental inhomogeneity and only minor second phase formation.
| Original language | English |
|---|---|
| Pages (from-to) | 35-43 |
| Number of pages | 9 |
| Journal | Journal of Nuclear Materials |
| Volume | 483 |
| DOIs | |
| State | Published - Jan 1 2017 |
Funding
This research was sponsored by the U.S. Department of Energy , Office of Nuclear Energy , for the Light Water Reactor Sustainability Research and Development Effort. The authors would like to thank Dr. T. S. Byun from Oak Ridge National Laboratory (ORNL) for his fruitful discussions on the results and D.P. Stevens for assisting in preparations of this manuscript. This manuscript has been authored by the Oak Ridge National Laboratory, managed by UT-Battelle LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes.
