Engineering Significance of Ferrite Grain Size on the Radiation Sensitivity of Pressure Vessel Steels

2009 ◽  
pp. 48-48-19 ◽  
Author(s):  
G. M. Gordon ◽  
H. H. Klepfer
Keyword(s):  
Grain Size ◽  
Pressure Vessel ◽  
Radiation Sensitivity ◽  
Pressure Vessel Steels ◽  
Engineering Significance ◽  
Ferrite Grain Size

Carbon analysis in reactor pressure vessel steels

1983 ◽  
Vol 41 ◽  
pp. 222-223
Author(s):  
O.C. de Hodgins ◽  
B.L. Shriver ◽  
K.R. Lawless
Keyword(s):  
Carbon Atom ◽  
Pressure Vessel ◽  
Radiation Sensitivity ◽  
Carbon Activity ◽  
Transmission Electron ◽  
Pressure Vessel Steels ◽  
Finite Distance ◽  
Iron Ferrite ◽  
Substitutional Atom

The effect of neutron irradiation on the notch ductility transition temperature (NDTT) of A533B steel is known to be affected by the activity of the carbon atom which would be affected by its nearest neighboring substitutional atom, that is, silicon, manganese, etc. The high carbon activity resulting from increased nickel and silicon promotes the formation of vacancy complexes which produce irradiation hardening and, therefore, higher NDTT shifts.The present study has been undertaken to clarify the role of carbon and impurities in A533-B steel in the mechanism of neutron embrittlement, two specimens of A533-B pressure vessel steels differing in radiation sensitivity have been examined using transmission electron microscopy. The study showed that the carbon-vacancy complex in iron (ferrite) has a carbon atom positioned a finite distance from the vacancy along a <100> line. In some cases martensite was found, in others, a combination of martensite with ferrite.

Microstructural Control in Thick-Walled Nb-Ti-V Microalloyed Linepipe Steels

2004 ◽  
Vol 467-470 ◽  
pp. 223-228
Author(s):  
K.M. Banks
Keyword(s):  
Grain Size ◽  
Laboratory Simulation ◽  
Microalloyed Steels ◽  
Processing Parameter ◽  
Strip Rolling ◽  
Bearing Steels ◽  
Simulation Results ◽  
Linepipe Steels ◽  
Ferrite Grain Size ◽  
Microstructural Control

Various microstructure models for Nb-bearing steels were tested under industrial strip rolling conditions to establish a relationship between grain size and toughness in Ti-Nb-V microalloyed steels. For similar Nb contents, microstructure models for Nb steels were found to adequately describe recrystallisation kinetics in more complex Ti-Nb-V steels. For thick-walled linepipe (11.6mm), a minimum of 0.04%Nb is required to achieve adequate toughness. Retained strain was the dominant processing parameter factor affecting ferrite grain size. The predicted minimum amount of retained strain after the last pass required for sufficient grain refinement concurred with laboratory simulation results. For the rolling schedules investigated, metadynamic recrystallisation was predicted to occur during roughing, whilst static recrystallisation was predominant during finishing.

scholarly journals A Dislocation-Based Theory for the Deformation Hardening Behavior of DP Steels: Impact of Martensite Content and Ferrite Grain Size

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Yngve Bergström ◽  
Ylva Granbom ◽  
Dirk Sterkenburg
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Deformation Process ◽  
Volume Fraction ◽  
High Energy ◽  
Martensite Content ◽  
Plastic Deformation Process ◽  
Deformation Hardening ◽  
Dp Steels ◽  
Ferrite Grain Size

A dislocation model, accurately describing the uniaxial plastic stress-strain behavior of dual phase (DP) steels, is proposed and the impact of martensite content and ferrite grain size in four commercially produced DP steels is analyzed. It is assumed that the plastic deformation process is localized to the ferrite. This is taken into account by introducing a nonhomogeneity parameter, f(ε), that specifies the volume fraction of ferrite taking active part in the plastic deformation process. It is found that the larger the martensite content the smaller the initial volume fraction of active ferrite which yields a higher initial deformation hardening rate. This explains the high energy absorbing capacity of DP steels with high volume fractions of martensite. Further, the effect of ferrite grain size strengthening in DP steels is important. The flow stress grain size sensitivity for DP steels is observed to be 7 times larger than that for single phase ferrite.

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