The Structure and Properties of Stainless Steels after Exposure at Elevated Temperatures

2009 ◽  
pp. 237-237-13
Author(s):  
A. B. Wilder ◽  
E. F. Ketterer
Keyword(s):  
Stainless Steels ◽  
Elevated Temperatures ◽  
Structure And Properties

Derivation of Design Fatigue Curves for Austenitic Stainless Steel Grades 1.4541 and 1.4550 Within the German Nuclear Safety Standard KTA 3201.2

2013 ◽  
Author(s):  
Xaver Schuler ◽  
Karl-Heinz Herter ◽  
Jürgen Rudolph
Keyword(s):  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
Nuclear Safety ◽  
Safety Standard ◽  
Fatigue Design ◽  
Steel Grades ◽  
Best Fit

Titanium and niobium stabilized austenitic stainless steels X6CrNiTi18-10S (material number 1.4541, correspondent to Alloy 321) respectively X6CrNiNb18-10S (material number 1.4550, correspondent to Alloy 347) are widely applied materials in German nuclear power plant components. Related requirements are defined in Nuclear Safety Standard KTA 3201.1. Fatigue design analysis is based on Nuclear Safety Standard KTA 3201.2. The fatigue design curve for austenitic stainless steels in the current valid edition of KTA 3201.2 is essentially identical with the design curve included in ASME-BPVC III, App I (ed. 2007, add. July 2008 respectively back editions). In the current code revision activities of KTA 3201.2 the compatibility of latest in air fatigue data for austenitic stainless steels with the above mentioned grades were examined in detail. The examinations were based on statistical evaluations of 149 strain controlled test data at room temperature and 129 data at elevated temperatures to derive best-fit mean data curves. Results of two additional load controlled test series (at room temperature and 288°C) in the high cycle regime were used to determine a technical endurance limit at 107 cycles. The related strain amplitudes were determined by consideration of the cyclic stress strain curve. The available fatigue data for the two austenitic materials at room temperature and elevated temperatures showed a clear temperature dependence in the high cycle regime demanding for two different best-fit curves. The correlation of the technical endurance limit(s) at room temperature and elevated temperatures with the ultimate strength of the materials is discussed. Design fatigue curves were derived by application of the well known factors to the best-fit curves. A factor of SN = 12 was applied to load cycles correspondent to the NUREG/CR-6909 approach covering influences of data scatter, surface roughness, size and sequence. In terms of strain respectively stress amplitudes in the high cycle regime, for elevated temperatures (>80°C) a factor of Sσ = 1.79 was applied considering and combining in detail the partial influences of data scatter surface roughness, size and mean stress. For room temperature a factor of Sσ = 1.88 shall be applied. As a result, new design fatigue curves for austenitic stainless steel grades 1.4541 and 1.4550 will be available within the German Nuclear Safety Standard KTA 3201.2. The fatigue design rules for all other austenitic stainless steel grades will be based on the new ASME-BPVC III, App I (ed. 2010) design curve.

Cryogenic Temperature Dependence of the Yield Strength of High-Strength Alloys

1966 ◽  
Vol 88 (1) ◽  
pp. 117-128 ◽  
Author(s):  
C. T. Yang
Keyword(s):  
Yield Strength ◽  
Stainless Steels ◽  
General Equation ◽  
Cryogenic Temperature ◽  
Elevated Temperatures ◽  
High Strength ◽  
Cryogenic Temperatures ◽  
Test Range ◽  
Titanium Nickel ◽  
Straight Lines

The effect of cryogenic temperatures (from 78 F to −423 F) on the yield strength of twenty alloys was studied. Experimental results prove that they do not conform to any of the following theories: Hollomon and Zener’s, Cottrell and Bilby’s, or Fisher’s. However, all the plottings in loge-loge scale of yield strength versus absolute cryogenic temperatures of these alloys fall on straight lines which are governed by one single general equation, σy = bT−m. From the Cottrell’s dislocation theory on yielding and Fisher’s equation of activation energy in forming a dislocation loop, the same type of equation of yield strength versus temperature as expressed by the empirical ones can be derived theoretically. The empirical equations are very useful in predicting yield strengths at any cryogenic temperature within or slightly out of the test range for which data were available. Some limited yield strength data at elevated temperatures for a few alloys were studied for comparison. It was observed the general equation for yield strength versus cryogenic temperatures holds valid for stainless steels but not so well for titanium, nickel, and aluminum alloys at elevated temperatures. However, no conclusion can be drawn until further detailed studies at elevated temperatures are made.

Structure and properties of double-layered powder membranes based on palladium and stainless steels

1991 ◽  
Vol 30 (12) ◽  
pp. 1039-1043
Author(s):  
V. P. Georgiev ◽  
P. Ya. Zlatkov ◽  
V. M. Kaptsevich ◽  
V. V. Savich ◽  
V. K. Sheleg
Keyword(s):  
Stainless Steels ◽  
Structure And Properties

INTERMETALLIC COMPOUND AlxTi – ARE PROMISING MATERIAL FOR HIGH ELEVATED TEMPERATURES (review) Part 1. The crystaline structure and properties of the intermetallic compound Al2Ti

2021 ◽  
pp. 28-43
Author(s):  
N.A. Nochovnaya ◽  
◽  
V.I. Ivanov ◽  
L.Yu. Avilochev ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compound ◽  
Lamellar Structure ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Texture Formation ◽  
Structure And Properties ◽  
High Temperature Alloys ◽  
Transformation Mechanisms ◽  
Increased Strength

The Al2Ti intermetallic compound is the most promising base for high-temperature alloys designed for advanced power plants. This work provides an overview of the structures of binary alloys concerning to the Ti–Al system, as well as the phase transformation mechanisms and the peculiarities of plastic deformation of alloys. The alloys which phase composition is represented by a mixture of r-Al2Ti+γ-TiAl with a lamellar structure show anomalous mechanical properties depending on texture formation and grain size. These alloys possess increased strength and decreased plasticity at elevated temperatures.

Structure and properties of borided chromium stainless steels

1985 ◽  
Vol 27 (5) ◽  
pp. 391-394
Author(s):  
E. V. Vasil'eva ◽  
I. I. Yurkov ◽  
A. M. Urlapov ◽  
G. A. Mel'nichuk
Keyword(s):  
Stainless Steels ◽  
Structure And Properties

Measurement of the Absorption of Microwave Power by Corroded Metals

1988 ◽  
Vol 124 ◽  
Author(s):  
Ralph W. Bruce ◽  
R. A. Quar
Keyword(s):  
Stainless Steels ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Surface Conductivity ◽  
Metallic Alloys ◽  
Metal Alloys ◽  
Electrical Measurements ◽  
Organic Mixture ◽  
Heat Treated ◽  
Microwave Signals

ABSTRACTMetal alloys, when exposed to a salt/organic environment at elevated temperatures, corrode resulting in a decrease in the surface conductivity. This decrease can be monitored and assessed via the measurement of the incident and reflected microwave signals impinging upon the corroded surface. Several metallic alloys, stainless steels and inconels, were treated with a salt/organic mixture (proprietary) and heat treated at 1100 F. Periodically, the metals were removed from the furnace, allowed to cool to room temperature, and measured electrically. The samples were re-coated with the salt/organic mixture and re-heat treated. The electrical measurements showed a generally increased power absorption as corrosion thickness increased.

On Creep Rupture Characteristics in STS304 Stainless Steels

2006 ◽  
Vol 326-328 ◽  
pp. 1309-1312
Author(s):  
Seon Jin Kim ◽  
Yu Sik Kong ◽  
Young Join Noh ◽  
Won Taek Jung ◽  
Sang Woo Kwon
Keyword(s):  
Steady State ◽  
Creep Rate ◽  
Stress Exponent ◽  
Stainless Steels ◽  
Elevated Temperatures ◽  
Creep Rupture ◽  
Steady State Creep ◽  
Rupture Time ◽  
Steady State Creep Rate ◽  
Creep Stress

In this study, the creep rupture tests of STS304 stainless steels were investigated at three different elevated temperatures of 600, 650 and 700 under the constant creep stresses. Creep rupture characteristics such as creep stress, creep rupture time, steady state creep rate and so on were evaluated. The behaviors of creep rate curve and initial strain are compared at three different elevated temperatures. The stress exponent (n) at 600, 650 and 700 based on steady state creep rate showed 22.5, 20.6 and 11.4 respectively. By increasing the temperature, the stress exponent is decreased. At the temperature of 700, the lowest stress exponents are shown and this behavior is also observed in the case of stress exponent based on rupture time. The creep life prediction by LMP method is presented and the equation of this result is as follows: T(logtr+20)=-0.005152-14.56+24126.

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