scholarly journals The role of grain boundary ferrite evolution and thermal aging on creep cavitation of type 316H austenitic stainless steel

2021 ◽  
Vol 807 ◽  
pp. 140859
Author(s):  
S. He ◽  
H. Shang ◽  
A. Fernández-Caballero ◽  
A.D. Warren ◽  
D.M. Knowles ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Thermal Aging ◽  
Creep Cavitation ◽  
Grain Boundary Ferrite

Role of Long Term Ageing on the Creep Life of Type 316H Austenitic Stainless Steel Bifurcation Weldments

2016 ◽  
Author(s):  
Ana I. Martinez-Ubeda ◽  
Ian Griffiths ◽  
Oliver D. Payton ◽  
Charles M. Younes ◽  
Tom B. Scott ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Chemical Composition ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Creep Damage ◽  
M23c6 Carbide ◽  
Boiler Tube ◽  
Boundary Length

Intergranular creep cracks have been observed in the heat affected zone of the 316H austenitic stainless steel superheater boiler tube bifurcation weldments after long term service at temperature of ∼550°C. The cracking mechanism is believed to be creep dominated. Moreover, chemical composition of defective material compared with similar uncracked components suggests that composition influences susceptibility to creep cracking. A systematic characterization of ratios number of creep cavities/grain boundary length and inter-granular precipitation length/grain boundary length has been undertaken in HAZ of three samples extracted from plants with different specific compositions. Here, the role of precipitation on creep deformation and fracture is explored. Precipitates of both ferrite and M23C6 carbide arising from long term service and associated creep cavitation have been identified using transmission electron microscopy. The creep damage and cracking, and therefore overall service life creep, is discussed by consideration of susceptibility of creep cavity nucleation and subsequently growth arising from specific differences in the chemical composition of the three boiler tube bifurcations.

Sensitization control in AISI 316L(N) austenitic stainless steel: Defining the role of the nature of grain boundary

2009 ◽  
Vol 51 (9) ◽  
pp. 2144-2150 ◽  
Author(s):  
N. Parvathavarthini ◽  
S. Mulki ◽  
R.K. Dayal ◽  
I. Samajdar ◽  
K.V. Mani ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Aisi 316L

Origin and Role of Σ3 Boundaries during Thermo-Mechanical Processing of a Ti-Modified Austenitic Stainless Steel

2011 ◽  
Vol 702-703 ◽  
pp. 714-717 ◽  
Author(s):  
Sumantra Mandal ◽  
A.K. Bhaduri ◽  
V. Subramanya Sarma
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Hot Deformation ◽  
Cold Deformation ◽  
Grain Boundary Engineering ◽  
Annealing Twins ◽  
High Fraction ◽  
Deformation Tests

The origin and role of S3 boundaries during dynamic recrystallization (DRX) and grain boundary engineering (GBE) of a Ti-modified austenitic stainless steel (alloy D9) is studied. Hot deformation tests were carried out on solution-annealed (SA) specimens to study the DRX behavior whereas a series of cold deformation and annealing were performed on SA specimens to realize GBE microstructure. A linear relationship between the area fraction of DRX and the number fraction of Σ3 boundaries was observed during hot deformation. This high fraction of Σ3 boundaries could account for the formation of coherent annealing twins by “growth accidents” during DRX. For certain combinations of cold deformation and annealing, a significant increase in S3 boundaries was observed. In contrast to hot deformation, majority of these new S3 boundaries during cold deformation and annealing were formed by geometrical interactions between the pre-existing Σ3 boundaries. The role of the S3 boundaries during DRX and on tailoring microstructure through grain boundary engineering approach is discussed.

Effect of Thermo-Mechanical History on Reheat Cracking in 316H Austenitic Stainless Steel Weldments

2010 ◽  
Author(s):  
Bo Chen ◽  
Michael W. Spindler ◽  
David J. Smith ◽  
Peter E. J. Flewitt
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Creep Deformation ◽  
Deformation Behaviour ◽  
Thick Section ◽  
Cavitation Damage ◽  
Reheat Cracking ◽  
Creep Cavitation ◽  
Designed Experiment

Reheat cracking has been observed in the heat affected zone of the 316H austenitic stainless steel thick section weldments during service at a temperature of ∼500°C. This has been attributed to the creep dominated relaxation of the highly triaxial residual stresses. Here the role of thermo-mechanical variables that contribute to the susceptibility of thick section 316H austenitic stainless steel weldments is briefly reviewed. The influence of the plastic strain, carbide precipitation and impurity element segregation on the subsequent creep deformation behaviour and the susceptibility to creep cavitation damage is discussed. A systematically designed experiment which includes these parameters has been undertaken for a 316H austenitic stainless steel. In addition, residual stress profiles have been introduced into cylindrical pre-treated specimens and the relaxation of these profiles with heat treatment has been measured by neutron diffraction. The experimental results are considered with respect to the effect of the microstructure on subsequent creep deformation and stress relaxation. The susceptibility to intergranular brittle fracture is discussed and an attempt is made to correlate the microstructure and stress state factors encountered in the HAZ with the accumulation of the creep cavitation associated with reheat cracking.

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