ASTM G 124 Test Data For Selected Al-Si Alloys, Al-Composites, Binary Alloys and Stainless Steels

Author(s):  
JR De Wit ◽  
TA Steinberg ◽  
JP Haas
2009 ◽  
Vol 413-414 ◽  
pp. 725-732 ◽  
Author(s):  
Xiao Cong He

The aim of this study is to investigate the creep-fatigue behavior of stainless steel materials. Based on the elevated-temperature tensile, creep and rupture test data, thermal creep-fatigue modelling was conducted to predict the failure life of stainless steels. In the low cycle thermal fatigue life model, Manson’s Universal Slopes equation was used as an empirical correlation which relates fatigue endurance to tensile properties. Fatigue test data were used in conjunction with different modes to establish the relationship between temperature and other parameters. Then creep models were created for stainless steel materials. In order to correlate the results of short-time elevated temperature tests with long-term service performance at more moderate temperatures, different creep prediction models, namely Basquin model, Sherby-Dorn model and Manson-Haferd model, were studied. Comparison between the different creep prediction models were carried out for a range of stresses and temperatures. A linear damage summation method was used to establish life prediction model of stainless steel materials under creep-fatigue.


2017 ◽  
Vol 741 ◽  
pp. 88-93 ◽  
Author(s):  
Kunio Hasegawa ◽  
Saburo Usami

The fatigue crack growth threshold ΔKth is an important characteristic of crack growth assessment for the integrity of structural components. However, the accurate threshold ΔKth values for austenitic stainless steels in air environment are lacking in many fitness-for-service (FFS) codes, although fatigue crack growth tests have been performed and many test data had been published. This paper focuses on fatigue crack growth threshold ΔKth values for austentic stainless steel in air environment. The paper introduces the current ΔKth values provided by four major FFS codes and summarizes the available test data based on the literature survey. The paper then discusses the applicability of the existing ΔKth for stainless steels and proposes a new relation as a function of the stress ratio (the R ratio) for use by FFS codes.


Author(s):  
Poh-Sang Lam ◽  
Andrew J. Duncan ◽  
Michael J. Morgan ◽  
Robert L. Sindelar ◽  
Thad M. Adams

Archival materials test data on austenitic stainless steels for service in high pressure hydrogen gas has been reviewed. The bulk of the data were from tests conducted prior to 1983 at the Savannah River Laboratory, the predecessor to the Savannah River National Laboratory, for pressures up to 69 MPa (10,000 psi) and at temperatures within the range from 78 to 400 K (−195 to 127 °C). The data showed several prominent effects and correlations with test conditions: • There was a significant reduction in tensile ductility as measured by reduction of area or by the total elongation with hydrogen. Hydrogen effects were observed when the specimens were tested in the hydrogen environment, or the specimens were precharged in high pressure hydrogen and tested in air or helium. • There was a significant reduction in fracture toughness with hydrogen (and sometimes in tearing modulus which is proportional to the slope of the crack resistance curve). • The effects of hydrogen on ductility can be correlated to the nickel content of the iron-chromium-nickel steels. The optimal nickel content to retain the high tensile ductility in these alloys was 10 to at least 20 wt. %. • The effects of hydrogen can be correlated to the grain size. Large grain sizes exhibited a greater loss of ductility compared to small grain sizes. The Savannah River Laboratory test data, especially those not readily available in the open literature, along with the sources of the data, are documented in this paper.


Author(s):  
Jun-Young Jeon ◽  
Dong-Il Ryu ◽  
Yun-Jae Kim ◽  
Mi-Yeon Lee ◽  
Jin-Weon Kim

In this study, a method to predict fracture toughness of aged cast austenitic stainless steels (CASSs) using small punch (SP) test and finite element (FE) analysis is proposed. Grade CF8M is considered and thermally aged up to 5,000 hours at 400°C. SP tests and fracture toughness test using compact tension (C(T)) specimen are conducted with virgin (unaged) and aged CF8M. FE analyses performed in this study use ductile fracture simulation technique with ‘the multi-axial fracture strain model’. The multi-axial fracture strain model for each aged CF8M are determined from SP test data and FE analyses. Fracture toughness of aged CF8M are predicted by conducting fracture toughness test simulations using FE damage analyses. Predicted fracture toughness results are compared with C(T) data to validate the method suggested in this study. The predicted initiation toughness values are predicted well and fracture toughness values are slightly conservative compared to test data.


Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.


Author(s):  
J. J. Laidler ◽  
B. Mastel

One of the major materials problems encountered in the development of fast breeder reactors for commercial power generation is the phenomenon of swelling in core structural components and fuel cladding. This volume expansion, which is due to the retention of lattice vacancies by agglomeration into large polyhedral clusters (voids), may amount to ten percent or greater at goal fluences in some austenitic stainless steels. From a design standpoint, this is an undesirable situation, and it is necessary to obtain experimental confirmation that such excessive volume expansion will not occur in materials selected for core applications in the Fast Flux Test Facility, the prototypic LMFBR now under construction at the Hanford Engineering Development Laboratory (HEDL). The HEDL JEM-1000 1 MeV electron microscope is being used to provide an insight into trends of radiation damage accumulation in stainless steels, since it is possible to produce atom displacements at an accelerated rate with 1 MeV electrons, while the specimen is under continuous observation.


Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.


Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D.J. Matlock ◽  
W.W. Fisher ◽  
P.M. Tarin ◽  
...  

Coherent annealing-twin boundaries are constant structure and energy interfaces with an average interfacial free energy of ∼19mJ/m2 versus ∼210 and ∼835mJ/m2 for incoherent twins and “regular” grain boundaries respectively in 304 stainless steels (SS). Due to their low energy, coherent twins form carbides about a factor of 100 slower than grain boundaries, and limited work has also shown differences in Cr-depletion (sensitization) between twin versus grain boundaries. Plastic deformation, may, however, alter the kinetics and thermodynamics of twin-sensitization which is not well understood. The objective of this work was to understand the mechanisms of carbide precipitation and Cr-depletion on coherent twin boundaries in deformed SS. The research is directed toward using this invariant structure and energy interface to understand and model the role of interfacial characteristics on deformation-induced sensitization in SS. Carbides and Cr-depletion were examined on a 20%-strain, 0.051%C-304SS, heat treated to 625°C-4.5h, as described elsewhere.


Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D.J. Matlock ◽  
W.W. Fisher ◽  
P.M. Tarin ◽  
...  

Plastic deformation is a key variable producing accelerated intergranular (IG) carbide precipitation and chromium-depletion (sensitization) development in stainless steels. Deformation above 20% also produces transgranular (TG) carbides and depletion in the material. Research on TG carbides in SS is, however, limited and has indicated that the precipitation is site-specific preferring twin-fault intersections in 316 SS versus deformation-induced martensite and martensite lath-boundaries in 304 SS. Evidences indicating the relation between martensite and carbides were, however, sketchy.The objective of this work was to fundamentally understand the relationship between TG carbides and strain-induced martensite in 304 SS. Since strain-induced martensite forms at twin-fault intersections in 304 SS and the crystallography of the transformation is well understood, we believed that it could be key in understanding mechanisms of carbides and sensitization in SS. A 0.051% C, 304 SS deformed to ∽33% engineering strain (40% true strain) and heat treated at 670°C/ 0.1-10h was used for the research. The study was carried out on a Hitachi H-8000 STEM at 200 kV.


Author(s):  
S. Wisutmethangoon ◽  
T. F. Kelly ◽  
J.E. Flinn

Vacancies are introduced into the crystal phase during quenching of rapid solidified materials. Cavity formation occurs because of the coalescence of the vacancies into a cluster. However, because of the high mobility of vacancies at high temperature, most of them will diffuse back into the liquid phase, and some will be lost to defects such as dislocations. Oxygen is known to stabilize cavities by decreasing the surface energy through a chemisorption process. These stabilized cavities, furthermore, act as effective nucleation sites for precipitates to form during aging. Four different types of powders with different oxygen contents were prepared by gas atomization processing. The atomized powders were then consolidated by hot extrusion at 900 °C with an extrusion ratio 10,5:1. After consolidation, specimens were heat treated at 1000 °C for 1 hr followed by water quenching. Finally, the specimens were aged at 600 °C for about 800 hrs. TEM samples were prepared from the gripends of tensile specimens of both unaged and aged alloys.


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