Sensitivity of the Creep-Rupture Properties of Waspaloy Sheet to Sharp-Edged Notches in the Temperature Range 1000–1400 Deg F

1972 ◽  
Vol 94 (1) ◽  
pp. 13-21 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Necessary Conditions ◽  
Rupture Life ◽  
Creep Rupture ◽  
Optimum Combination ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Notched Specimen ◽  
Solution Treated ◽  
Material Solution ◽  
Rupture Properties

Time-dependent notch sensitivity of Waspaloy was observed at test temperatures from 1000 to 1300 deg F. Its occurrence in this range was dependent on the heat treatment. “Overaging” eliminated the notch sensitivity. Optimum combination of smooth and notched specimen strengths for material solution treated at 1975 deg F were obtained by aging 24 hr at 1550 deg F. Necessary conditions for time-dependent notch sensitivity were (i) the notch specimen loads had to be below the approximate 0.2 percent off set yield strength; and (ii) test data from smooth specimens had to indicate that small amounts of creep used up large fractions of creep-rupture life. No reasons were evident why these criteria will not prove applicable to other alloys.

Creep–rupture model of aluminum alloys: Cohesive zone approach

2014 ◽  
Vol 229 (8) ◽  
pp. 1343-1347 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Aluminum Alloys ◽  
Cohesive Zone ◽  
Rupture Life ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Time Dependent ◽  
Element Analysis ◽  
Rupture Model ◽  
Term Creep

In this article, a creep–rupture model of aluminum alloys is developed using a time-dependent cohesive zone law. For long-term creep rupture, a time jump strategy is used in a cohesive zone law. Stress–rupture scatter of aluminum alloy 4032-T6 is fitted with a power law form. Then, change in the slope of a stress-rupture line is identified on a log–log scale. Implicit finite element analysis is employed with a model containing a cohesive zone. Stress–rupture curves at various given temperatures are calculated and compared with experimental ones. Results show that a proposed method allows predicting creep–rupture life of aluminum alloys.

Capped End, Thin-Wall Tube Creep-Rupture Behavior for Type 316 Stainless Steel

1963 ◽  
Vol 85 (1) ◽  
pp. 71-86 ◽  
Author(s):  
G. H. Rowe ◽  
J. R. Stewart ◽  
K. N. Burgess
Keyword(s):  
Biaxial Tension ◽  
Rupture Life ◽  
Creep Rupture ◽  
Uniaxial Tensile ◽  
Thin Wall ◽  
Rupture Ductility ◽  
Statistical Argument ◽  
Stress Ratios ◽  
Rupture Properties ◽  
Rupture Behavior

The creep-rupture behavior of 34 capped end, thin-wall tubular specimens was correlated with results for 54 uniaxial tensile specimens in tests at 1350 F, 1500 F, and 1650 F. Basic tests established isotropy in creep-rupture properties as well as metallurgical stability for the material used in the study. Significant correlations of creep rate, rupture life, and rupture ductility were established for the cases of stress ratios 1/0 and 2/1 in the biaxial tension quadrant. Data from tests at 1500 F were evaluated for a statistical argument. This same material was subsequently utilized in a high temperature structures research program to be reported separately.

Notch Sensitivity, Mechanical, and Microstructural Characteristics of TD-NiCr at Elevated Temperatures

1974 ◽  
Vol 96 (2) ◽  
pp. 109-114 ◽  
Author(s):  
D. J. Wilson ◽  
A. Ferrari
Keyword(s):  
Inconel 718 ◽  
Mechanical Characteristics ◽  
Elevated Temperatures ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Microstructural Characteristics ◽  
Notched Specimen ◽  
Theoretical Concepts ◽  
Notched Specimens ◽  
Good Agreement

Tensile and creep-rupture tests were conducted for smooth and sharp edge-notched specimens of 0.015-in. (0.38 mm) thick TD-NiCr sheet at 1000 to 1800 deg F (538–982 deg C). The dislocation mechanisms operative were in good agreement with theoretical concepts. Time-dependent notch sensitivity was not observed. The notched specimen behavior correlated with the same mechanical characteristics and microstructural features as previously established for Waspaloy and Inconel 718 which are strengthened by coherent precipitates.

Effects of Surface Recrystallization on the Microstructures and Creep Properties of Single Crystal Superalloy DD6

2010 ◽  
Vol 638-642 ◽  
pp. 2279-2284
Author(s):  
Jia Rong Li ◽  
Feng Li Sun ◽  
Ji Chun Xiong ◽  
Shi Zhong Liu ◽  
Mei Han
Keyword(s):  
Single Crystal ◽  
Annealing Temperature ◽  
Low Cost ◽  
Rupture Life ◽  
Creep Rupture ◽  
Single Crystal Superalloy ◽  
Recrystallization Temperature ◽  
Creep Properties ◽  
Grit Blasting ◽  
Rupture Properties

This work assesses the effects of the surface recrystallization of the processing of water grit blasting, grit blasting and mechanically polishing on the microstructures and creep rupture properties of DD6 alloy, a low-cost second generation single crystal superalloy. The results demonstrate that the possibility and the depth of the surface recrystallization of DD6 show an increase as the annealing temperature increases from 1050°C to 1250°C. No surface recrystallization happens when the specimens of the alloy have been undergone at 1100°C for 4 hours after water grit blasting, but the surface recrystallization occurs at the annealing temperature above 1200°C for 4 hours after water grit blasting. The test indicates that the increasing pre-deformation decreases the surface recrystallization temperature. The creep rupture life of DD6 alloy without processing is 274.4 hours, 341.1 hours at the conditions of 980°C/250MPa, 1070°C/140MPa respectively. After annealing at 1100°C for 4 hours, the creep rupture life of the alloy with the processing of water grit blasting is equivalent to that of the alloy without processing. The surface recrystallization of the alloy happens with the processing of grit blasting after the annealing at 1100°C for 4 hours, and there is a reduction of the creep rupture life at the conditions as mentioned above. The creep properties of DD6 alloy meet the needs of blades and vanes of single crystal for advanced aeroengines when the surface recrystallization of the alloy occurs during manufacturing and processing.

scholarly journals Influence of normalizing and tempering temperatures on the creep properties of P92 steel

2020 ◽  
Vol 39 (1) ◽  
pp. 178-188
Author(s):  
Lakshmiprasad Maddi ◽  
Atul Ramesh Ballal ◽  
Dilip Ramkrishna Peshwe ◽  
M. D. Mathew
Keyword(s):  
Power Plants ◽  
Rupture Strength ◽  
Rupture Life ◽  
Creep Rupture ◽  
Laves Phases ◽  
P92 Steel ◽  
Creep Properties ◽  
Martensitic Microstructure ◽  
Actual Service ◽  
Rupture Properties

AbstractP92 steel is used as a piping material in ultra super critical power plants that can be operated at steam temperatures up to 650°C. The changes in the martensitic microstructure of P92 steel must be evaluated thoroughly before it is put into actual service. In this study, indigenously developed P92 steel was used. The steel was subjected to normalizing and tempering heat treatments in the range of 1,040–1,060°C and 740–780°C. The changes in the microstructure were evaluated and creep-rupture properties were studied at test temperatures of 600 and 650°C. Although normalizing temperatures influenced the microstructure and creep strength marginally, the change in tempering temperatures led to significant changes. The creep rupture strength at 600°C was influenced largely by the changes in the dislocation substructure, while the precipitation of Laves phases was a significant observation made for 650°C test temperature. Proposed mechanisms for the microstructural evolution and its consequences on the rupture life are discussed in this study.

Creep Life Evaluations of ASME B31.1 Allowance for Variation From Normal Operations: 11 Materials

2019 ◽  
Author(s):  
Marvin J. Cohn ◽  
Ron Haupt
Keyword(s):  
Base Metal ◽  
Rupture Life ◽  
Creep Damage ◽  
Creep Rupture ◽  
Creep Life ◽  
Material Creep ◽  
Metal Creep ◽  
Life Consumption ◽  
Rupture Properties ◽  
Design Pressure

Abstract The ASME B31.1-2018 Power Piping Code (Code) paras. 102.2.4, 102.3.3, and 104.8.2 provide an allowance regarding operating above the design temperature and design pressure for short time periods. The concept of allowing occasional operation for short periods of time at higher than the design pressure or design temperature has been in the Code since 1967. These 1967 Code para. 102.2.4 limitations were based on engineering judgment that can now be quantitatively evaluated for the additional creep life consumption (creep rupture damage accumulation). This study primarily is a quantitative estimate of the permitted increased life consumption, considering minimum creep rupture properties, associated with the 2018 Code operating allowances for piping materials operating in the creep range. Eleven base metal materials are considered in this paper — low carbon steel, 1.25Cr 0.5Mo, 2.25Cr 1Mo, 9Cr 1 Mo V, Type 304 SS, Type 316 SS, Type 316L SS, Type 321 SS, Type 321H SS, Type 347 SS, and Type 347H SS. Results of this evaluation may be used to improve the ASME B31.1 Code, including a technical basis for a possible revision to para. 102.2.4. Previous studies have revealed that Grade P22 base metal creep damage is slightly more sensitive to stress than Grade P11 material creep rupture damage, and Grade P91 base metal creep damage is substantially more sensitive to stress than Grade P22 material creep rupture damage. Therefore, the allowable pressure and temperature variations result in a range of increased creep life consumption for different materials. The intent of this study was to modify the two Code allowance criteria so that the permitted increased creep life consumption (considering the minimum creep rupture properties of the material) of Allowance B is about the same amount as the increased creep life consumption result of Allowance A for the same material. Consequently, this study was performed to realign the allowable increased creep rupture life consumption of Allowance B to be approximately equivalent to the allowable increased creep life consumption of Allowance A. If the Allowance B event duration is increased from 80 hours per year to 400 hours per year, the Allowance B increased creep life consumption is slightly less than the Allowance A life consumption for each of these materials.

Tensile and Creep Rupture Properties of Co + Co3AIC0.5 Two-Phase Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
R. Ishibashi ◽  
S. Nakamura ◽  
Y. Aono ◽  
S. Miura ◽  
Y. Mishima
Keyword(s):  
Tensile Strength ◽  
Volume Fraction ◽  
Tensile Axis ◽  
Rupture Life ◽  
Creep Rupture ◽  
Average Particle ◽  
Phase Volume ◽  
Two Phase ◽  
Phase Volume Fraction ◽  
Rupture Properties

ABSTRACTIt is expected that the κ-phase of the intermetallic compound Co3A1C0.5 would strengthen Cobase alloys used at high temperatures like the γ' -phase of Ni-base superalloys. Tensile and creep rupture properties of Co+κ two-phase alloys with κ-phase volume fractions up to 0.75 were investigated. Alloy samples made by directional solidification casting were annealed at 1573 K for 3.6 ks and at 1373 K for 28.8 ks in vacuum, followed by Ar gas cooling. Tensile tests at RT and 1073 K and creep rupture tests at 1089 K under a stress of 172 MPa were conducted with the tensile axis parallel to the solidification direction. In alloys with low κ-phase volume fraction, cuboidal K-precipitates with average particle diameters of 0.4 to 1.0 μm were observed. They were coherent with the Co(fcc) matrix with misfits of about 3%. As the κ-phase volume fraction increased, tensile strength also increased. The alloy with κ-phase volume fraction of 0.4 had a 0.2% proof stress of 817MPa, tensile strength of 1047 MPa at RT, creep rupture life of 1.43 Ms, and tensile strain higher than 10%. These strengths are better than those of the conventional Co-base alloys. However, ductility of alloys with κ-phase volume fraction larger than 0.4 decreased due to large eutectic and primary κ-phase particles.

Study on Creep Behaviors of T92 Steel under Multiaxial Stress State

2013 ◽  
Vol 860-863 ◽  
pp. 774-779
Author(s):  
Xue Ping Mao ◽  
Yang Yu ◽  
Chao Li ◽  
Sai Dong Huang ◽  
Hong Xu ◽  
...  
Keyword(s):  
Stress State ◽  
Rupture Life ◽  
Creep Damage ◽  
Creep Rupture ◽  
Failure Behavior ◽  
Multiaxial Stress ◽  
Creep Tests ◽  
Creep Ductility ◽  
Notched Specimen ◽  
Multiaxial Stress State

Creep tests for smooth specimens and notched specimens of T92 steel were carried out to study the effect of multiaxial stress state on creep rupture behaviors at 650°C. Creep rupture life was estimated by representative stress at multiaxial state of stress, the failure behavior of multiaxial creep was analyzed, and Kachanov creep damage formula was used to analyze the experimental data. The results show that the notch strengthens rupture life, multiaxial rupture behavior is controlled by mixed parameters, the creep ductility of the smooth and notched specimen decreases with rupture time, and damage factors of the smooth specimen and notched specimen are similar according to Kachanov formula.

scholarly journals Relationship of Mechanical Characteristics and Microstructural Features to the Time-Dependent Edge-Notch Sensitivity of Inconel 718 Sheet

1973 ◽  
Vol 95 (2) ◽  
pp. 112-123 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Inconel 718 ◽  
Mechanical Characteristics ◽  
Rupture Life ◽  
Dislocation Motion ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Motion Mechanism ◽  
Notched Specimens ◽  
Edge Notch ◽  
Relationship Of

Time-dependent notch sensitivity of Inconel 718 sheet was observed at 900 deg F to 1200 deg F (482–649 deg C). It occurred when edge-notched specimens were loaded below the yield strength and smooth specimen tests showed that small amounts of creep consumed large rupture life fractions. The severity of the notch sensitivity was reduced by decreasing the temperature of the solution treatments, increasing the time and/or temperature of aging and increasing the test temperature to 1400 deg F (760 deg C). Elimination of time-dependent notch sensitivity correlated with a change in dislocation motion mechanism from shearing to bypassing precipitate particles.

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