Comparison of Microstructure & Mechanical Properties between Mn-Mo-Ni and Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels

Cited 6 time in webofscience Cited 0 time in scopus
  • Hit : 380
  • Download : 0
Application of a stronger and more durable material for reactor pressure vessels (RPVs) might be an effective way to insure the integrity and increase the efficiency of nuclear power plants. A series of research projects to apply the SA508 Gr.4 steel in ASME code to RPVs are in progress because of its excellent strength and durability compared to commercial RPV steel (SA508 Gr.3 steel). In this study, the microstructural characteristics and mechanical properties of SA508 Gr.3 Mn-Mo-Ni low alloy steel and SA508 Gr.4N Ni-Mo-Cr low alloy steel were investigated. The differences in the stable phases between these two low alloy steels were evaluated by means of a thermodynamic calculation using ThermoCalc. They were then compared to microstructural features and correlated with mechanical properties. Mn-Mo-Ni low alloy steel shows the upper bainite structure that has coarse cementite in the lath boundaries. However, Ni-Mo-Cr low alloy steel shows the mixture of lower bainite and tempered martensite structure that homogeneously precipitates the small carbides such as M(23)C(6) and M(7)C(3) due to an increase of hardenability and Cr addition. In the mechanical properties, Ni-Mo-Cr low alloy steel has higher strength and toughness than Mn-Mo-Ni low alloy steel. Ni and Cr additions increase the strength by solid solution hardening. In addition, microstructural changes from upper bainite to tempered martensite improve the strength of the low alloy steel by grain refining effect, and the changes in the precipitation behavior by Cr addition improve the ductile-brittle transition behavior along with a toughening effect of Ni addition.
Publisher
KOREAN INST METALS MATERIALS
Issue Date
2010
Language
Korean
Article Type
Article
Keywords

HIGH-STRENGTH; BEHAVIOR; FRACTURE; IRON

Citation

KOREAN JOURNAL OF METALS AND MATERIALS, v.48, no.3, pp.194 - 202

ISSN
1738-8228
DOI
10.3365/KJMM.2010.48.03.194
URI
http://hdl.handle.net/10203/93970
Appears in Collection
RIMS Journal Papers
Files in This Item
There are no files associated with this item.
This item is cited by other documents in WoS
⊙ Detail Information in WoSⓡ Click to see webofscience_button
⊙ Cited 6 items in WoS Click to see citing articles in records_button

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0