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Title: Mechanical Properties of Irradiated 9Cr-2WVTa Steel With and Without Nickel

Authors:
 [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1207040
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 367-370
Country of Publication:
United States
Language:
English

Citation Formats

Klueh, Ronald L, and Sokolov, Mikhail. Mechanical Properties of Irradiated 9Cr-2WVTa Steel With and Without Nickel. United States: N. p., 2007. Web. doi:10.1016/j.jnucmat.2007.03.160.
Klueh, Ronald L, & Sokolov, Mikhail. Mechanical Properties of Irradiated 9Cr-2WVTa Steel With and Without Nickel. United States. doi:10.1016/j.jnucmat.2007.03.160.
Klueh, Ronald L, and Sokolov, Mikhail. Mon . "Mechanical Properties of Irradiated 9Cr-2WVTa Steel With and Without Nickel". United States. doi:10.1016/j.jnucmat.2007.03.160.
@article{osti_1207040,
title = {Mechanical Properties of Irradiated 9Cr-2WVTa Steel With and Without Nickel},
author = {Klueh, Ronald L and Sokolov, Mikhail},
abstractNote = {},
doi = {10.1016/j.jnucmat.2007.03.160},
journal = {Journal of Nuclear Materials},
number = ,
volume = 367-370,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The effects of aluminum content on mechanical properties of a 9Cr-0.5Mo-1.8W steel have been investigated. It was found that aluminum addition had a beneficial effect on toughness, but significantly reduced the creep resistance of the steel, especially on the long-term side. Examination of the microstructure and precipitation characteristics revealed that almost all of the aluminum added existed as AlN-type nitrides after normalizing and tempering. The undissolved AlN in high aluminum steels resulted in a dramatic refinement of prior austenite grains, which contributed to the improvement of toughness and was also partially responsible for the decreased creep rupture strength. The formationmore » of AlN suppressed the precipitation of VN-type nitride; AlN also provided formation sites for Nb(C, N) and M{sub 23}C{sub 6} type, which had an equivalent effect to the coalescence of these precipitates on AlN, resulting in the reduction of precipitate density and, therefore, decreased creep resistance.« less
  • No abstract prepared.
  • An Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel has excellent strength and impact toughness before and after irradiation in the Fast Flux Test Facility and the High Flux Reactor (HFR). The ductile-brittle transition temperature (DBTT) increased only 32 C after 28 dpa at 365 C in FFTF, compared to a shift of {approx}60 C for a 9Cr-2WV steel--the same as the 9Cr-2WVTa steel but without tantalum. This difference occurred despite the two steels having similar tensile but without tantalum. This difference occurred despite the two steels having similar tensile properties before and after irradiation. The 9Cr-2WVTa steel has a smaller prior-austenite grain size, butmore » otherwise microstructures are similar before irradiation and show similar changes during irradiation. The irradiation behavior of the 9Cr-2WVTa steel differs from the 9Cr-2WV steel and other similar steels in two ways: (1) the shift in DBTT of the 9Cr-2WVTa steel irradiated in FFTF does not saturate with fluence by {approx}28 dpa, whereas for the 9Cr-2WV steel and most similar steels, saturation occurs at <10 dpa, and (2) the shift in DBTT for 9Cr-2WVTa steel irradiated in FFTF and HFR increased with irradiation temperature, whereas it decreased for the 9Cr-2WV steel, as it does for most similar steels. The improved properties of the 9Cr-2WVTa steel and the differences with other steels were attributed to tantalum in solution.« less
  • The authors studied the effects of copper, nickel and boron on the mechanical properties of low-alloy steel weld metals deposited at high heat input by the submerged arc process. The copper and nickel contents of the welds were systematically varied within the ranges of 0.03 to 0.89 wt-% Cu and 0.01 to 1.54 wt-% Ni. In addition, several of these copper and nickel combinations were duplicated with welds containing 36 to 44 ppm B. Tensile testing revealed yield strengths, R[sub p0.2], in the range from 462 to 546 MPa, and ultimate tensile strengths, R[sub m], from 638 to 869 MPa.more » The weld metal Charpy V-notch (CVN) data showed a 35 J transition temperature, ITT[sub 35j], ranging from [minus]28 to 55 C. Upon adding boron, patches of intergranular fracture were present on the CVN fracture surfaces. This was particularly true when boron was added at the higher copper and nickel levels. Qualitative metallographic examinations revealed the presence of extensive amounts of particles at the prior austenite grain boundaries in boron containing welds. Furthermore, adding boron at the higher copper and nickel levels promoted the formation of the MAC (martensite-austenite-carbide) microconstituent. Also nickel seemed to promote formation of MAC in reheated weld metal. At this high heat input (4.8 kJ/mm), additions of copper, nickel and boron did not improve the mechanical properties.« less