Decomposition of the solid solution in austenitic steels alloyed with nitrogen

1977 ◽  
Vol 19 (2) ◽  
pp. 159-161
Author(s):  
L. K. Gordienko ◽  
L. F. Usova ◽  
T. N. Simonova
Keyword(s):  
Solid Solution ◽  
Austenitic Steels

Progress in Creep-Resistant Steels for High Efficiency Coal-Fired Power Plants

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Fujio Abe
Keyword(s):  
Solid Solution ◽  
Creep Strength ◽  
Power Plants ◽  
Precipitation Hardening ◽  
High Efficiency ◽  
Austenitic Steels ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
Creep Resistant Steels ◽  
Grade 91

Recent progress in creep-resistant bainitic, martensitic, and austenitic steels for high efficiency coal-fired power plants is comprehensively reviewed with emphasis on long-term creep strength and microstructure stability at grain boundaries (GBs). The creep strength enhanced ferritic (CSEF) steels, such as Grade 91 (9Cr–1Mo–0.2V–0.05Nb), Grade 92 (9Cr–0.5Mo–1.8W–VNb), and Grade 122 (11Cr–0.4Mo–2W–1CuVNb), can offer the highest potential to meet the required flexibility for ultra-supercritical (USC) power plants operating at around 600 °C, because of their smaller thermal expansion and larger thermal conductivity than austenitic steels and Ni base alloys. Further improvement of creep strength of martensitic 9 to 12Cr steels has been achieved by substituting a part or all of Mo with W and also by the addition of Co, V, Nb, and boron. A martensitic 9Cr–3W–3Co–VNb steel strengthened by boron and MX nitrides, designated MARBN, exhibits not only much higher creep strength of base metal than Grade 91, Grade 92, and Grade 122 but also substantially no degradation in creep strength due to type IV fracture in welded joints at 650 °C. High-strength bainitic 2.25 to 3Cr steels have been developed by enhancing solid solution hardening due to W and precipitation hardening due to (V,Nb)C carbides in bainitic microstructure. The improvement of creep strength of austenitic steels has been achieved by solid solution hardening due to the addition of Mo, W, and nitrogen and by precipitation hardening due to the formation of fine MX (M = Ti, Nb, X = C, N), NbCrN, M23C6, Cu phase, and Fe2(Mo,W) Laves phase. The boundary and sub-boundary hardening are shown to be the most important strengthening mechanism in creep of creep-resistant steels and is enhanced by fine dispersions of precipitates along boundaries.

A Concept for Development of Hydrogen-Resistant Austenitic Steels

2013 ◽  
Author(s):  
Valentin Gavriljuk ◽  
Bela Shanina ◽  
Vladyslav Shyvanyuk ◽  
Sergey Teus
Keyword(s):  
Solid Solution ◽  
Hydrogen Embrittlement ◽  
Solid Solutions ◽  
Austenitic Steels ◽  
Hydrogen Degradation ◽  
Hydrogen Atoms ◽  
Free Electrons ◽  
Physical Reason ◽  
Hydrogen Resistance

Austenitic steels represent a promising class of engineering materials for hydrogen use in vehicles, e.g. for tanks and pipelines. This topic is analyzed in terms of the effect of alloying elements on the interatomic bonds in the solid solutions and, consequently, on the interaction between hydrogen atoms and dislocations and hydrogen embrittlement, HE. The effect of Cr, Ni, Mn, Mo, Si, Al, Cu, C, N was studied. It is shown that the physical reason for HE amounts to the hydrogen-caused increase in the concentration of free electrons in the austenitic solid solution. For this reason, the alloying with elements decreasing the concentration of free electrons is expected to improve resistance of austenitic steels to HE. Alloying with Cr, Mn, Mo and Si is shown to be useful, whereas Cu, Al, Ni, N assist hydrogen degradation. The role of Ni amounts only to stabilization of the fcc austenitic lattice and its absence or the decrease of its content in steel is desirable. Based on the obtained results, recommendations are made for design of austenitic steels with increased hydrogen resistance.

On The Mechanism of Formation of Stacking Faults in Aged Nickel-Base Alloys

1968 ◽  
Vol 26 ◽  
pp. 262-263 ◽  
Author(s):  
G. M. Rowe ◽  
W. H. Rand ◽  
B. H. Kear
Keyword(s):  
Solid Solution ◽  
Base Alloy ◽  
Stacking Faults ◽  
Austenitic Steels ◽  
Nickel Base Alloy ◽  
Mechanism Of Formation ◽  
Solution Treated ◽  
Segregation Effect ◽  
Chemical Segregation ◽  
Nickel Base

The formation of stacking faults upon aging a solution treated and quenched nickel-base alloy has been reported previously. More recent work has revealed a similar behavior in several γ’ precipitation hardened nickel-base alloys aged in the temperature range l400°-1650°F. The faults intersect both γ (nickel solid solution) and γ’ (Ni3Al solid solution) phases, and are of extrinsic type. Fault formation is attributed to a chemical segregation effect involving the climb of Frank partials, similar to that reported for austenitic steels.Fig. 1 shows extrinsic faults associated with a slip band in Udimet 700 lightly deformed at 70°F prior to aging. For the specified [011] normal to the foil, the slip trace is (11), and the faults lie in (111) and (11). Using the g · b = 0 or ± 1/3 (s = 0) criterion for dislocation invisibility, Figs, 1 (a-c) show that the outer partial for a (111) fault must be 1/6 [11] Shockley, or 1/3 [111] Frank.

Decomposition of the solid solution in austenitic steels with carbon and nitrogen

1972 ◽  
Vol 14 (7) ◽  
pp. 574-577
Author(s):  
V. D. Verner ◽  
G. A. Tolmacheva ◽  
L. F. Usova ◽  
V. A. Zvereva
Keyword(s):  
Solid Solution ◽  
Austenitic Steels ◽  
Carbon And Nitrogen

Features of Swelling in Modified Austenitic Steels

2005 ◽  
Vol 475-479 ◽  
pp. 1437-1440
Author(s):  
V. Voyevodin ◽  
V. Bryk ◽  
O. Borodin ◽  
I.M. Neklyudov ◽  
N. Akasaka ◽  
...  
Keyword(s):  
Solid Solution ◽  
Defect Structure ◽  
Point Of View ◽  
Austenitic Steels ◽  
Cooperative Interaction ◽  
Swelling Behaviour ◽  
Solution Decay

Results of analysis of swelling behaviour of alloying austenitic steels are described from the point of view of the cooperative interaction of defect structure, solid solution decay and precipitates evolution.

Sign in / Sign up

Export Citation Format

Share Document