Link of the critical temperature of brittleness with the geometry of the stress concentrator and loading rate

1991 ◽  
Vol 23 (12) ◽  
pp. 1303-1308
Author(s):  
V. M. Mishin ◽  
I. V. Kislyuk ◽  
V. I. Sarrak
Keyword(s):  
Critical Temperature ◽  
Stress Concentrator ◽  
Loading Rate ◽  
Critical Temperature Of Brittleness

Methodological Features of WWER RPV Metal Critical Temperature of Brittleness Prediction on the Base of the Data Scatter and the Chemical Composition

2015 ◽  
Author(s):  
Igor Orynyak ◽  
Maksym Zarazovskii ◽  
Sergii Radchenko
Keyword(s):  
Critical Temperature ◽  
Chemical Composition ◽  
Charpy Impact ◽  
Thermal Ageing ◽  
Surveillance Program ◽  
Initial State ◽  
Predictive Values ◽  
Integrity Assessment ◽  
Critical Temperature Of Brittleness ◽  
The One

For WWER-1000 reactor pressure vessel (RPV) the metal embrittlement monitoring is performed with the usage of the radiation and the temperature surveillance specimens (SS) sets. For the fracture toughness curve indexing the critical temperature of brittleness (CTB) is used, CTB is obtained by the processing of Charpy impact energy data. Modern codes that regulate WWER RPVs CTB prediction are based on the CTB shift ideology. According to this ideology the CTB is defined as the initial CTB value plus CTB shift due to the radiation, plus CTB shift due to the thermal ageing, plus certain margin. This margin includes the scatter of CTB in the initial state, scatter of CTB shift due to the radiation and scatter of CTB shift due to the thermal ageing. A tendency of modern WWER RPV integrity assessment codes to provide conservatism with: choosing the CTB in the initial state for the CTB shifts determination; choosing the CTB in the initial state for the CTB determination; taking into account the scatter of CTB in the initial state, scatter of CTB shift due to the radiation and scatter of CTB shift due to the thermal ageing, leads to huge predictive values of CTB and to formal unfulfillment of brittle fracture criterion for RPVs. This paper demonstrates that the usage of actual CTB data and their scatter (obtained directly from Charpy V-notched impact tests) instead of the shift ideology can be the one of the possible ways of adequate CTB prediction. The CTB database for welds is created on the base of the results of WWER-1000 RPV surveillance program of all Ukrainian NPPs. The article presents the results of the thermal aged Charpy V-notched SS tests. The thermal aging has been shown to be practically absent. The CTB thermal shift values, which were obtained in some laboratories, are caused by the CTB scattering in initial and thermal aged states only. According to the processing results of the irradiated SS tests data, the chromium, manganese and silicon have been found to have the greatest impact on the CTB value. The CTB dependence on the neutron fluence and chemical composition of WWER-1000 RPV beltline welds has been obtained. A new methodology of CTB curve prediction for WWER-1000 RPV welds is developed. This methodology is expected to be the basis in the modern Ukrainian normative of RPV integrity assessment since it reduces the unreasonably high conservatism inherent to the RPV project, to a more reasonable level.

Optical properties of the Vanadium dioxide

2015 ◽  
Vol 8 (2) ◽  
pp. 2148-2155 ◽  
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Energy Efficiency ◽  
Optical Properties ◽  
Critical Temperature ◽  
Thin Layer ◽  
Dielectric Function ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Practical Utility ◽  
Infra Red

The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature

Effect of loading rate on cohesive parameters of the adhesive Araldite 2015

2020 ◽  
Vol 62 (9) ◽  
pp. 943-949
Author(s):  
Engin Erbayrak ◽  
Halil Ozer
Keyword(s):  
Loading Rate

ALLEGHENY STAINLESS TYPE 405

Alloy Digest ◽  
1985 ◽  
Vol 34 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Critical Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Ductile Material ◽  
Air Cooling ◽  
Temperature Performance

Abstract ALLEGHENY STAINLESS Type 405, unlike most other 12% chromium steels, is not subject to appreciable hardening through air cooling from high temperatures. This is an advantageous characteristic in those applications where a soft, ductile material is required after rapid cooling from above the critical temperature. The nonhardening tendency of Type 405 also retards the formation of hardening cracks where welding is employed. Its uses include annealing boxes and baffles where hardening during cooling would be undesirable. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating and machining. Filing Code: SS-461. Producer or source: Allegheny Ludlum Corporation.

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