Development of Austenitic Stainless Steels with Improved Resistance to Elevated-Temperature Irradiation Embrittlement

2009 ◽  
pp. 261-261-29 ◽  
Author(s):  
E. E. Bloom ◽  
J. R. Weir
Keyword(s):  
Elevated Temperature ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Irradiation Embrittlement ◽  
Temperature Irradiation

Contributions of Dr. Sumio Yukawa in the Development of Non-Ductile Failure Prevention Rules in the ASME Code

2008 ◽  
Author(s):  
Hardayal S. Mehta
Keyword(s):  
Elevated Temperature ◽  
Carbon Steel ◽  
Stainless Steels ◽  
Pressure Vessel ◽  
Nickel Alloys ◽  
Ductile Failure ◽  
Austenitic Stainless Steels ◽  
Current Status ◽  
Asme Code

The objective of this paper is to review and highlight the contributions of Dr. Sumio Yukawa in the development of rules for the prevention of non-ductile failure in the ASME Boiler and Pressure Vessel Code. This includes review of his role in the development of WRC-175, Appendix G of Section III, the development of early flaw evaluation rules for carbon steel piping and in the review and evaluation of the toughness of austenitic stainless steels and nickel alloys after long-term elevated temperature exposures. The current status of these activities is briefly described.

scholarly journals Characterization of Austenitic Stainless Steels Deformed at Elevated Temperature

2017 ◽  
Vol 48 (10) ◽  
pp. 4525-4538 ◽  
Author(s):  
Mattias Calmunger ◽  
Guocai Chai ◽  
Robert Eriksson ◽  
Sten Johansson ◽  
Johan J. Moverare
Keyword(s):  
Elevated Temperature ◽  
Stainless Steels ◽  
Austenitic Stainless Steels

Molybdenum solubility differences in MC phases formed in titanium and niobium modified austenitic stainless steels determined using AEM

1984 ◽  
Vol 42 ◽  
pp. 496-497
Author(s):  
P. J. Maziasz
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Elevated Temperature ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
304 Stainless Steel ◽  
Elevated Temperature Strength ◽  
Helium Embrittlement ◽  
Type 304 ◽  
Type 304 Stainless Steel

Molybdenum is added to improve elevated temperature strength and corrosion resistance for type 316 compared to type 304 stainless steel. Strong carbide forming elements, like titanium and niobium, are also added to these steels to improve creep strength and reduce stress corrosion cracking, as well as to improve resistance to irradiation induced swelling and helium embrittlement. This work shows that fairly pure TiC and NbC form in Ti- and Nb- stabilized versions of type 304 stainless steel (types 321 and 347, respectively); however, the Ti-rich MC dissolves Mo considerably whereas the NbC remains compositionally quite pure when these phases form in Ti- and Nb- modified type 316 stainless steels, respectively.

A Fatigue Crack Growth Model for Type 304 Austenitic Stainless Steels in an Elevated Temperature Air Environment

2021 ◽  
Author(s):  
Kathleen C. Barron
Keyword(s):  
Fatigue Crack ◽  
Elevated Temperature ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Reference Curve ◽  
Paris Law ◽  
R Ratio ◽  
Type 304

Abstract The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI utilizes reference fatigue crack growth rate (FCGR) curves for flaw evaluations. The current ASME reference curve for austenitic stainless steels in air environments is a Paris-Law relation with a single ΔK exponent that covers the entire ΔK range. Since generation of the model that became the ASME reference curve, extensive additional FCGR testing of Type 304, Type 304L, and Type 304/304L dual-certified stainless steel and the corresponding weld metal has been performed in an elevated temperature air environment. This testing revealed fatigue crack growth (FCG) behaviors that were not adequately captured by the ASME reference curve. In particular, the ASME reference curve failed to capture a flattening of the FCGR curve in the intermediate ΔK range before the FCGRs sharply dropped off as the threshold behavior is approached. Additionally, the FCGR data showed a slight frequency-dependence. Based on this new data, a new FCGR model was generated for Type 304 austenitic stainless steels in air environments between 250°C and 338°C. A tri-linear Paris-Law style correlation was chosen for the updated FCGR model to accommodate both the flattening of the FCGR curve at intermediate ΔK levels and the sharp downturn in the near-threshold ΔK regime. Each of the three branches of the FCGR curve exhibit a different R-ratio dependence, with the near-threshold regime being the most sensitive to changes in the R-ratio.

Fracture Mechanics Based Asset Management Approach in SCC Environments

2019 ◽  
Author(s):  
David Segletes ◽  
Christopher Tipple ◽  
Daniel Peters
Keyword(s):  
Elevated Temperature ◽  
Fracture Mechanics ◽  
Stainless Steels ◽  
Heat Affected Zone ◽  
Asset Management ◽  
Austenitic Stainless Steels ◽  
Management Approach ◽  
Operating Cycle ◽  
Temperature And Pressure ◽  
Weld Heat

Abstract The operation of autoclave vessels at elevated temperature and pressure is common across a variety of industries. Many of the older operating vessels were fabricated from multiple forgings by welding. Austenitic stainless steels are the material of choice for many of these vessels, and precautions to prevent sensitization in the weld heat affected zone may not have been implemented during construction, which can increase susceptibility to environmental cracking conditions. Recently a vessel developed a through wall leak during the operating cycle. Three complimentary vessels at the same facility were inspected resulting in one additional vessel not returning to service and two with similar flaws. A multi-disciplinary approach was used to evaluate the failure, perform a fitness for service determination, and nondestructive examinations to monitor the flaw growth and validate the fitness for service inputs. The overall approach is discussed.

scholarly journals Elastic Properties of FeCr20Ni8Xn (X = Mo, Nb, Ta, Ti, V, W and Zr) Austenitic Stainless Steels: A First Principles Study

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 145 ◽  
Author(s):  
Yuchen Dou ◽  
Hong Luo ◽  
Jing Zhang
Keyword(s):  
Elevated Temperature ◽  
Shear Modulus ◽  
Elastic Properties ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
First Principles ◽  
High Performance ◽  
Austenitic Stainless Steels ◽  
Iron Matrix ◽  
Precipitation Processes

Austenitic stainless steels suffer from intergranular corrosion and stress corrosion cracking when exposed to elevated temperature (500–800 °C). Under these environments, Cr-carbides and Cr-carbontrides precipitate at the grain boundaries, which results in the formation of Cr-depleted zone. In practice, alloying elements could be added into austenitic stainless steels to modify the precipitation processes. Besides the precipitation processes, the elastic properties of the iron matrix would be influenced. Using the exact muffin-tin orbitals (EMTO) method, the solute effects on the elastic properties of FeCr20Ni8 austenitic stainless steels were studied. Based on the simulated shear modulus (G) and bulk modulus (B), we proposed a design map for FeCr20Ni8 based alloys, aiming to provide a basis for the design of high-performance austenitic stainless steels.

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