Assessment of the propensity of low creep ductility for optimized Grade 92 steel
A total of twenty-five optimized Grade 92 (Opt.G92) samples were tested at 550, 600, and 650°C in air with stresses ranging from 90 to 280 MPa. Two types of Opt.G92 heats were studied in this work, with one type only fabricated by vacuum induction melting (VIM) and the other type by both VIM and electro-slag remelting (VIM+ESR). All the samples were in the as-received thermomechanical treatment (TMT) condition, except for one sample in the re-normalized and tempered (Re-N&T) condition. Three of the samples are still running, with the longest test time >39,863 h at 550°C. In general, the creep-ruptured samples exhibited consistently superior creep resistance, in terms of longer time to rupture, higher creep strength, and lower minimum creep rate, compared to Grades 92 and 91. For example, Opt.G92 with TMT increased creep strength by ~50 and ~60 MPa with minimum creep rate about two orders of magnitude lower than P92 and P91, respectively, at 550°C. The ongoing test of the Opt.G92 sample in the Re-N&T condition also showed significant enhancement in creep resistance. Although the enhancement in creep resistance of Opt.G92 over P92 and P91 became smaller at higher temperatures, the enhancement is still noticeable at 650°C.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1484118
- Report Number(s):
- ORNL/TM-2018/972
- Country of Publication:
- United States
- Language:
- English
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