scholarly journals The Role of Deformation in Coarsening of M23C6 Carbide Particles in 9% Cr Steel

2020 ◽  
Vol 121 (8) ◽  
pp. 804-810
Author(s):  
E. S. Tkachev ◽  
A. N. Belyakov ◽  
R. O. Kaibyshev
Keyword(s):  
M23c6 Carbide ◽  
Carbide Particles

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.

M 4 C 3 precipitation in Fe–C–Mo–V steels and relationship to hydrogen trapping

2006 ◽  
Vol 462 (2072) ◽  
pp. 2315-2330 ◽  
Author(s):  
S Yamasaki ◽  
H.K.D.H Bhadeshia
Keyword(s):  
Kinetic Theory ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Hydrogen Atoms ◽  
Elastic Interactions ◽  
Dissolved Hydrogen ◽  
Coherency Strains ◽  
Carbide Particles

Strong steels suffer from embrittlement due to dissolved hydrogen, a phenomenon which can be mitigated by trapping the hydrogen at carbide particles, where it is rendered benign. The precipitation and coarsening of plate-like M 4 C 3 carbides, during the tempering of quaternary Fe–C–Mo–V martensitic steels, has been characterized both experimentally and by developing appropriate kinetic theory. The trapping capacity is found to peak when the carbides are about 10 nm in length, indicating a role of coherency strains in trapping hydrogen atoms via elastic interactions. This suggests a method for developing alloys which are better able to resist the detrimental effects of hydrogen.

The role of dislocations in the coarsening of carbide particles dispersed in ferrite

1975 ◽  
Vol 32 (1) ◽  
pp. 61-72 ◽  
Author(s):  
G. L. Dunlop ◽  
R. K. W. Honeycombe
Keyword(s):  
Carbide Particles

scholarly journals IMPACT OF USE ON RELEASE PROCESSES IN AUSTENITIC STEEL TP347HFG

2021 ◽  
Vol 72 (4) ◽  
pp. 22-26
Author(s):  
Hanna Purzyńska ◽  
Grzegorz Golański ◽  
Michał Kwiecień ◽  
Dariusz Paryż
Keyword(s):  
Grain Boundaries ◽  
Austenitic Steel ◽  
M23c6 Carbide ◽  
Σ Phase ◽  
Precipitation Processes ◽  
Austenite Grains ◽  
Carbide Particles ◽  
M23c6 Carbides ◽  
Large Primary ◽  
Release Processes

The article presents an analysis of precipitation processes in heat-resistant TP347HFG steel after 41,000 h of operation at 585°C. Microstructure investigation showed that the use of the tested steel resulted mainly in the precipitation processes occurring at grain boundaries. Identification of the precipitates showed the presence of M23C6 carbides and σ phase particles along boundaries. Single M23C6 carbide particles were revealed also at twin boundaries. Inside austenite grains, apart from large, primary precipitates, finely-dispersed secondary NbX particles (X = C,N) were also observed.

scholarly journals Precipitation of M23C6 Secondary Carbide Particles in Fe-Cr-Mn-C Alloy during Heat Treatment Process

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Nguyen Thi Hoang Oanh ◽  
Nguyen Hoang Viet
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Treatment Process ◽  
Volume Fraction ◽  
M23c6 Carbide ◽  
Stable Phase ◽  
Heat Treatment Process ◽  
Heat Treated Sample ◽  
The Matrix ◽  
Carbide Particles

The initial as-cast microstructure of high-chromium white cast iron (2.08% C, 12.1% Cr), including austenitic dendrites in a matrix of a eutectic mixture of austenite and M7C3 carbides. Heat treatment of as-cast iron leads to a transformation of the matrix from austenite to martensite phase. The secondary M23C6 carbide precipitated from matrix improving the hardness of sample from 48 HRC to 62 HRC. JMatPro simulations of volume fraction phase for Fe-C-Cr-Mn alloy shows M7C3 and austenite phases are stable at austenitization temperature (1000 °C). Eutectic carbide of M7C3 is a stable phase in the alloy which is undissolved in the matrix during the heat treatment process. The HR-TEM images of heat-treated sample revealed that both eutectic M7C3 carbide and ultrafine secondary M23C6 carbide particles distributed on the martensite matrix.

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