Long-Term Creep Ductility Minima in 12%CrMoV Steel

1991 ◽  
pp. 146-159 ◽  
Author(s):  
R. Timmins ◽  
P. F. Aplin
Keyword(s):  
Creep Ductility ◽  
Term Creep

Microstructure and Creep Properties of AISI 316LN Steels with Niobium Additions

2005 ◽  
Vol 482 ◽  
pp. 275-278 ◽  
Author(s):  
Vlastimil Vodárek ◽  
Gabriela Rožnovská ◽  
Jaromír Sobotka
Keyword(s):  
S Phase ◽  
Creep Life ◽  
Creep Ductility ◽  
Niobium Content ◽  
Creep Properties ◽  
Size Refinement ◽  
Tertiary Stage ◽  
Type Aisi ◽  
Term Creep

The long-term creep rupture tests have been carried out on three casts of a type AISI 316LN steel at 600 and 650°C. Two of the casts investigated contained additions of 0.1 and 0.3 wt.% of niobium. The growing niobium content strongly reduced the minimum creep rate and prolonged the time to the onset of the tertiary stage of creep and also shortened this stage. The enhanced creep resistance of niobium containing steels is not accompanied by the longer creep life that might have been expected. At both temperatures of creep exposure the niobium-bearing casts displayed an inferior creep ductility. Microstructural investigations revealed that niobium provoked significant grain size refinement and the formation of Z-phase. Particles of this phase were considerably dimensionally stable. Furthermore, niobium accelerated the formation and coarsening of s-phase, h-Laves and M6(C,N). The coarse intergranular particles facilitated the formation of cavities which resulted in intergranular failure mode.

scholarly journals Determination of Long-Term Creep Properties for 316H Steel Using Short-Term Tests on Pre-strained Material

2021 ◽  
Author(s):  
H. Zhou ◽  
A. Mehmanparast ◽  
K. Nikbin
Keyword(s):  
Mechanical Response ◽  
Tensile Tests ◽  
Primary Objective ◽  
Creep Rupture ◽  
Creep Ductility ◽  
Creep Properties ◽  
Material State ◽  
Term Creep

AbstractDetermination of long-term creep rupture properties for 316H steel is both costly and time-consuming and given the level of scatter in the data would need substantial number of tests to be performed. The primary objective of this study is to estimate the long-term creep properties of cross-weld (XW) and as-received (AR) 316H stainless steel by performing accelerated tests on pre-compressed (PC) material. In this work, uniaxial creep rupture tests have been performed on XW specimens and the results have been used to establish a correlation with accelerated test results on the PC material. Moreover, tensile tests have been performed on XW specimens at room temperature and 550 °C to examine the pre-conditioning effects on the mechanical response of the material. Similar power-law creep properties have been found for the creep strain rate and rupture time behaviour of the XW and PC specimens. It also has been found that the creep ductility data points obtained from XW and PC specimens fall upon the estimated trend for the AR material at 550 °C when the data are correlated with the applied stress normalised by 0.2% proof stress. The results show that the long-term creep properties of the XW and AR material can be estimated in much shorter time scales simply by performing tests on the PC material state.

Microstructural aspects of long-term creep ductility of AISI 316 LN steel

1985 ◽  
Vol 35 (3) ◽  
pp. 329-332
Author(s):  
M. Liška ◽  
M. Sobotková ◽  
J. Sobotka
Keyword(s):  
Creep Ductility ◽  
Aisi 316 ◽  
Term Creep

Statistical reinterpretation of the long term creep behaviour of the Ismetpasa segment of North Anatolian Fault, Turkey

2021 ◽  
pp. 228947
Author(s):  
Gokhan Gurbuz ◽  
Caglar Bayik ◽  
Saygin Abdikan ◽  
Kurtulus Sedar Gormus ◽  
Senol Hakan Kutoglu
Keyword(s):  
Creep Behaviour ◽  
North Anatolian Fault ◽  
Term Creep

Progress in Developing Constitutive Equations for Inelastic Design Analysis

1983 ◽  
Vol 105 (3) ◽  
pp. 273-276 ◽  
Author(s):  
C. E. Pugh
Keyword(s):  
Constitutive Equations ◽  
Inelastic Strain ◽  
Short Term ◽  
Inelastic Material ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Term Creep ◽  
Inelastic Design ◽  
Creep Deformations

A summary is given of the constitutive equations that have been developed for use in design assessments of elevated temperature components of liquid metal fast breeder reactors. The discussion addresses representations of short-term (plastic) and long-term (creep) inelastic material responses. Attention is given to improved representations of the interactions between plastic and creep deformations. Most of the discussion is in terms of constitutive equations that make use of the concept of separating the total strain into elastic, plastic, and creep portions. Additionally, some discussion is given of progress being made toward establishing design equations based on unified measures of inelastic strain that do not distinguish different strain portions.

Prediction of Long Term Stress Rupture Data for 2124

2006 ◽  
Vol 519-521 ◽  
pp. 1041-1046 ◽  
Author(s):  
Brian Wilshire ◽  
H. Burt ◽  
N.P. Lavery
Keyword(s):  
Q Methodology ◽  
Fracture Behavior ◽  
Stress Rupture ◽  
Creep Data ◽  
Short Term ◽  
Rupture Data ◽  
Term Creep ◽  
Term Data ◽  
Short Term Creep

The standard power law approaches widely used to describe creep and creep fracture behavior have not led to theories capable of predicting long-term data. Similarly, traditional parametric methods for property rationalization also have limited predictive capabilities. In contrast, quantifying the shapes of short-term creep curves using the q methodology introduces several physically-meaningful procedures for creep data rationalization and prediction, which allow straightforward estimation of the 100,000 hour stress rupture values for the aluminum alloy, 2124.

Influence of Stress on Degradation and Life Prediction of High Strength Ferritic Steels

2004 ◽  
Author(s):  
Kazuhiro Kimura ◽  
Kota Sawada ◽  
Kiyoshi Kubo ◽  
Hideaki Kushima
Keyword(s):  
Yield Stress ◽  
Elastic Limit ◽  
High Strength ◽  
Time To Rupture ◽  
Limit Stress ◽  
Creep Resistant Steels ◽  
Grade 91 ◽  
Term Creep ◽  
Grade 91 Steel

Influence of stress on creep deformation and degradation behavior has been investigated. Corresponding to inflection of stress vs. time to rupture curve, difference in recovery phenomena, that was homogeneous in short-term and inhomogeneous in long-term, was observed. Inflection of stress vs. time to rupture curve took place at the stress condition corresponding to half of 0.2% offset yield stress at the temperature. Elastic limit stress of Grade 91 steel was evaluated to be 150MPa at 600°C and 100MPa at 650°C, by means of stress abrupt change test. These stresses were found to be almost the same as half of 0.2% offset yield stress at the temperatures. Inflection of stress vs. time to rupture curve is caused by transient of applied stress from higher level than elastic limit to within elastic range. It has been concluded that long-term creep strength of ferritic creep resistant steels should be predicted from the selected creep rupture data under the stresses lower than elastic limit by considering half of 0.2% offset yield stress at the temperature, by means of Larson-Miller parameter with a constant of 20.

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