Comparison of Parameter Methods for Extrapolating High-Temperature Data

1959 ◽  
Vol 81 (4) ◽  
pp. 629-643 ◽  
Author(s):  
R. M. Goldhoff
Keyword(s):  
High Temperature ◽  
Stress Rupture ◽  
High Temperature Stress ◽  
Parameter Method ◽  
Time Data ◽  
Rupture Data ◽  
High Temperature Data ◽  
Long Time ◽  
Nimonic 80A ◽  
Short Time

The use of the controversial and contradictory parameter techniques in correlation of high-temperature stress-rupture data is discussed. They are treated with a view toward their application in extrapolating short-time data to predict working stresses in serviceable heat-resistant alloys. Three parameter methods are compared on a statistical basis for their ability to reproduce the isothermal data on which they are based and in particular the longest time data currently available and usable for this purpose. Comparisons are further made with long-time extrapolations based on direct plotting of test data. The materials chosen for evaluation are alloys S-590, A-286, Nimonic 80A, and 1Cr-1Mo-1/4V steel. It is shown that prediction of long-time working stresses using parameter techniques will generally give better results than can be obtained from long extrapolations on double logarithmic plots. Among the parameters themselves, the Manson-Haferd linear parameter method gave the most reliable extrapolations. However, the results obtained using the Larson-Miller method may be improved considerably if the proper constant is selected for each set of data rather than using C = 20 for all data. For reliable extrapolations all methods require data from tests up to 1000 hr and covering adequate ranges of stress and temperature.

Long Time High Temperature Stress Rupture Strength Behavior and Structure Stability Study on Ni-Base Superalloy Nimonic 80A

2016 ◽  
Vol 853 ◽  
pp. 148-152
Author(s):  
Xiao Fei Chen ◽  
Zhi Hao Yao ◽  
Mai Cang Zhang ◽  
Xi Shan Xie ◽  
Qiu Ying Yu ◽  
...  
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Rupture Strength ◽  
Stress Rupture ◽  
Structure Stability ◽  
Time Stress ◽  
Long Time ◽  
Nimonic 80A ◽  
Critical Requirement ◽  
Base Superalloy

Nimonic 80A Ni-base superalloy can be used for high temperature steam turbine components.There is a critical requirement for turbine blade application that the stress rupture strength for 105 hrs at relevant high temperatures should be higher than 100MPa.On the other hand, it must keep good structure stability and no harmful phase such as-phase and the TCP phase formation at long time high temperature exposure. Therefore, the long time stress rupture tests at temperatures of 600, 650, 680 and 700°C for different stresses have been carried out. The long time structure stability has been also studied in detail. The results show that Nimonic 80A can meet the critical requirement for USC steam turbine blades at 600~700°C. Any detrimental phases have not been found at the long time stress rupture tests. The morphology of grain boundary carbides also has no apparent change. Based on above mentioned results, Nimonic 80A is recommended to be used for USC steam turbine components in the temperature range of 600~650°C.

High Temperature Rupture Life of Nickel-Based Superalloy under Directional Solidification with High Temperature Gradient

2017 ◽  
Vol 898 ◽  
pp. 422-429 ◽  
Author(s):  
Wei Guo Zhang ◽  
Zhi Jie Liu ◽  
Song Ke Feng ◽  
Fu Zeng Yang ◽  
Lin Liu
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Temperature Stress ◽  
Solidification Rate ◽  
Rupture Life ◽  
Stress Rupture ◽  
High Temperature Stress ◽  
Stress Rupture Life ◽  
Nickel Based Superalloy

The stress rupture life of DZ125 nickel-based superalloy that was prepared by directional solidification process under the temperature gradient of 500 K/cm has been studied at 900°C and 235MPa. The results showed that with the increase of directional solidification rate from 50 μm/s to 800 μm/s, the primary dendrite arm spacing reduced from 94 μm to 35.8 μm and γ' precipitates reduced and more uniformed in size. The high temperature stress rupture life of as-cast sample increased firstly and then decreased and reached its maximum at the solidification rate of 500 μm/s. The dislocation configuration of sample with refine dendritic structure after stress rupture was investigated and discovered that the dislocations in different parts of sample had different morphology and density, which indicated that the deformation of as-cast samples were uneven during high temperature stress rupture. A lot of dislocations intertwined around carbides and at the interface of γ/γ', and the dislocation networks were destroyed and the dislocations entered γ' precipitate by the way of cutting.

Very-Short-Time, Very-High-Temperature Creep Rupture of Type 347 Stainless Steel and Correlation of Data

1969 ◽  
Vol 91 (1) ◽  
pp. 32-38 ◽  
Author(s):  
C. D. Lundin ◽  
A. H. Aronson ◽  
L. A. Jackman ◽  
W. R. Clough
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Minimum Creep Rate ◽  
Creep Rupture ◽  
Aisi Type ◽  
Data Scatter ◽  
Long Time ◽  
Short Time ◽  
Very High ◽  
Rupture Behavior

Available equipment initially developed for welding research studies was used to investigate the creep-rupture behavior of AISI type 347 stainless steel in a very-high-temperature range from 62 to 86 percent of the solidus. Stress applications from 900 to 28,000 psi gave rupture times from a fraction of a second to several hundred seconds with thousandfold variations of minimum creep rate. Results could be presented by conventional means. Data scatter on a Monkman-Grant plot was typical. Correlation and extrapolation procedures developed by Larson-Miller, Manson-Haferd, Dorn, Korchynsky, and Conrad for conventional long-time results were found to be applicable, with preference being given to the Manson-Haferd procedures.

A New Approach of Reliability Design for Creep Rupture Property

2009 ◽  
Author(s):  
Jie Zhao ◽  
Dong-ming Li ◽  
Yuan-yuan Fang ◽  
Shi-jie Zhu
Keyword(s):  
Parametric Method ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Parameter Method ◽  
Reliability Design ◽  
Safety Coefficient ◽  
Real Distribution ◽  
Z Parameter ◽  
Rupture Data ◽  
Temperature Time

It has been noted that the use of safety coefficient can deal with uncertainties existed in practical structures, while reliability concept provides more precise results by considering the real distribution of creep rupture property. Generally, creep rupture data of a heat-resistant steel can be compressed into a narrow band by using a temperature-time parametric method such as Larson-Miller or Manson-Haferd method. In order to describe the scattering of the data, the current paper proposes a “Z parameter” method to represent the magnitude of the deviation of the rupture data to master curve. Statistical analysis shows that the scattering of Z parameter for several types of steels is supported by normal distribution. Using this method, it is possible to achieve unified analysis of the creep rupture data in various temperature and stress conditions. Stress-TTP-Reliability curves (σ-TTP-R curves), Stress-Rupture time-Reliability curves (σ-tr-R curves) and Allowable stress-Temperature-Reliability curves ([σ]-T-R curves) are proposed which could embrace reliability concept into creep rupture property design.

scholarly journals Effect of Thermal Treatments on Quality and Aroma of Watermelon Juice

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yubin Wang ◽  
Wu Li ◽  
Yue Ma ◽  
Xiaoyan Zhao ◽  
Chao Zhang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Shelf Life ◽  
Color Difference ◽  
Thermal Treatments ◽  
Watermelon Juice ◽  
High Temperature Short Time ◽  
Long Time ◽  
Ultrahigh Temperature ◽  
Short Time

The effect of thermal treatments on the quality and aroma of watermelon juice was evaluated. Watermelon juice was pasteurized via ultrahigh temperature (UHT, pasteurized at 135°C for 2 s), low temperature long time (LTLT, pasteurized at 60°C for 30 min), and high temperature short time (HTST, pasteurized at 100°C for 5 min), respectively. UHT and LTLT reduced the total flora count and maintained the color of the pasteurized juice, while the HTST led to a significant color difference. A total of 27, 21, 22, and 21 volatiles were identified in the unpasteurized juice, UHT, LTLT, and HTST, respectively. The typical watermelon aroma, including (3Z)-3-nonen-1-ol, (E)-2-nonen-1-ol, 1-nonanal, (2E)-2-nonenal, and (E,Z)-2,6-nonadienal, was abundant in the LTLT. Consequently, the aroma of the LTLT was similar to that of unpasteurized juice. Moreover, the shelf life of the LTLT reached 101 and 14 days at 4 and 25°C, respectively. Hence, the LTLT was the best way to maintain the quality and aroma of watermelon juice.

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