Evaluation of Corrosion Degradation of 12Cr Alloy Steel Using an Ultrasonic Backward Radiation

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1653-1658 ◽  
Author(s):  
S. J. Song ◽  
Young H. Kim ◽  
D. H. Bae ◽  
M. H. Jung ◽  
S. D. Kwon
Keyword(s):  
Rayleigh Wave ◽  
Nondestructive Evaluation ◽  
Aging Time ◽  
Alloy Steel ◽  
Power Plants ◽  
Automated System ◽  
Rayleigh Surface Wave ◽  
Frequency Dependency ◽  
Angular Dependency ◽  
Backward Radiation

The corrosion degradation characteristics of the 12Cr alloy steel, which is widely used in fossil power plants as a turbine blade material, are evaluated nondestructively by use of the backward radiation of propagating Rayleigh wave. For this purpose, an automated system for measuring the ultrasonic backward radiation has been developed, and the frequency dependency of the Rayleigh surface wave has been investigated indirectly by observing the angular dependency of the acquired signals. The velocity of Rayleigh wave decreased as the increase of aging time, which implies the increase of the effective degraded layer thickness. And the peak amplitude of the radiation increased as aging time, which relates to the increase of inter-granular corrosion. The result observed in this study demonstrates high potential of the backward radiated ultrasound as a tool for nondestructive evaluation of the corrosion degradation characteristics of aged materials.

Assessment of Surface Damage in Thermally Aged FSX414 Cobalt-Based Superalloy Using Ultrasonic Rayleigh Wave

2005 ◽  
Vol 475-479 ◽  
pp. 651-654
Author(s):  
Jai Won Byeon ◽  
C.S. Kim ◽  
Y.H. Kim ◽  
S.I. Kwun ◽  
S.J. Hong
Keyword(s):  
Rayleigh Wave ◽  
Nondestructive Evaluation ◽  
Aging Time ◽  
Wave Velocity ◽  
Microstructural Analysis ◽  
Surface Damage ◽  
Rayleigh Surface Wave ◽  
Rayleigh Wave Velocity ◽  
Evaluation Parameters

An attempt was made to assess the surface damage in the isothermally degraded FSX414 Co-based superalloy using ultrasonic Rayleigh surface wave. Microstructural analysis (amount of solute Cr near the surface) and measurement of ultrasonic velocity and attenuation were performed after isothermal degradation heat treatment at 1100°C for up to 4000 hours. Rayleigh wave velocity was observed to increase with aging time, which was attributed to the increased depletion of Cr near the surface. Strong frequency dependence of Rayleigh wave velocity was found in the specimens with surface depletion layer. Attenuation coefficient of Rayleigh wave increased with increasing aging time. Therefore, both attenuation and velocity of ultrasonic Rayleigh wave are suggested as potential nondestructive evaluation parameters for the characterization of the thermally aged FSX414 superalloy.

Leaky Wave Contributions to Ultrasonic Scattering Amplitudes for Truncated Objects

1999 ◽  
Author(s):  
Philip L. Marston ◽  
Scot F. Morse ◽  
Karen Gipson
Keyword(s):  
Scattering Amplitudes ◽  
Rayleigh Wave ◽  
Nondestructive Evaluation ◽  
Cylindrical Shells ◽  
Leaky Wave ◽  
Leaky Waves ◽  
Ultrasonic Scattering ◽  
Ultrasonic Nondestructive Evaluation ◽  
Sonar Imaging

Abstract In ultrasonic nondestructive evaluation and sonar imaging, scattering contributions by leaky waves on truncated objects can be important for enhancing the visibility of certain of the borders of the scatterer. A method of approximating the leaky wave contributions is reviewed together with recent experimental and computational tests for evaluating that method in situations where the scattering contributions are large. The tests include meridional ray contributions to the scattering by tilted solid cylinders and cylindrical shells and Rayleigh wave contributions for steel cubes in water.

Rayleigh wave propagation at the boundary surface of dry sandy ($SiO_2$) thermoelastic solids

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shishir Gupta ◽  
Rishi Dwivedi ◽  
Smita Smita ◽  
Rachaita Dutta
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Rayleigh Wave ◽  
Penetration Depth ◽  
Dispersion Equation ◽  
Half Space ◽  
Rayleigh Waves ◽  
Secular Equation ◽  
Rayleigh Surface Wave ◽  
Content Type

Purpose The purpose of study to this article is to analyze the Rayleigh wave propagation in an isotropic dry sandy thermoelastic half-space. Various wave characteristics, i.e wave velocity, penetration depth and temperature have been derived and represented graphically. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Design/methodology/approach The present article deals with the propagation of Rayleigh surface wave in a homogeneous, dry sandy thermoelastic half-space. The dispersion equation for the proposed model is derived in closed form and computed analytically. The velocity of Rayleigh surface wave is discussed through graphs. Phase velocity and penetration depth of generated quasi P, quasi SH wave, and thermal mode wave is computed mathematically and analyzed graphically. To illustrate the analytical developments, some particular cases are deliberated, which agrees with the classical equation of Rayleigh waves. Findings The dispersion equation of Rayleigh waves in the presence of thermal conductivity for a dry sandy thermoelastic medium has been derived. The dry sandiness parameter plays an effective role in thermoelastic media, especially with respect to the reference temperature for η = 0.6,0.8,1. The significant difference in η changes a lot in thermal parameters that are obvious from graphs. The penetration depth and phase velocity for generated quasi-wave is deduced due to the propagation of Rayleigh wave. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Originality/value Rayleigh surface wave propagation in dry sandy thermoelastic medium has not been attempted so far. In the present investigation, the propagation of Rayleigh waves in dry sandy thermoelastic half-space has been considered. This study will find its applications in the design of surface acoustic wave devices, earthquake engineering structural mechanics and damages in the characterization of materials.

Nondestructive Evaluation of CVD Diamond Coating Layers Using the Leaky Rayleigh Surface Wave

2006 ◽  
Vol 326-328 ◽  
pp. 701-704 ◽  
Author(s):  
Wen Wu Wang ◽  
Sung Jin Song ◽  
Hak Joon Kim ◽  
Dong Ju Yang ◽  
Sung Duk Kwon
Keyword(s):  
Surface Wave ◽  
Nondestructive Evaluation ◽  
Coating Layer ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Diamond Coating ◽  
Rayleigh Surface Wave ◽  
Mechanical Parts ◽  
Time Trace ◽  
Cvd Diamond Coating

Chemical vapor deposit (CVD) diamond coating layer is expected to extend the lifetime of mechanical parts that are used severely abrasive conditions. However, one of the most severe problems is that the delamination between the CVD diamond coating layer and the silicon substrate occurs frequently due to large difference in the material properties. Therefore, the nondestructive evaluation of adhesive property of CVD diamond coating layer is needed. To address such a need, back-scattered Rayleigh surface wave is currently applied. However, the interpretation of the acquired signal is not easy at all. To take care of such a difficulty, we proposed the time trace angular scan (TTAS) plot and the frequency spectrum angular scan (FSAS) plot that can make possible of the systematic interpretation of the back-scattered signals from the diamond coating layer. In this paper, the concept of the TTAS and FSAS plots and the experimental results presented to demonstrate the effectiveness of the proposed approach.

Fracture Toughness in the Ductile-Brittle Transition and Thermal Ageing Behavior of Decarburized Heat Affected Zone of Alloy 52 Dissimilar Metal Welds of Nuclear Components

2014 ◽  
Author(s):  
Pierre Joly ◽  
Miguel Yescas ◽  
Elisabeth Keim
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Alloy Steel ◽  
Heat Affected Zone ◽  
Power Plants ◽  
Base Alloy ◽  
Thermal Ageing ◽  
Low Alloy Steel ◽  
Dissimilar Metal ◽  
Brittle Transition

Dissimilar metal welds (DMW) are used in nuclear power plants between the nozzles of main components in low alloy steel and stainless steel pipes, or safe-ends connected to the main coolant line pipes. AREVA proposes for EPR™ an improved design of DMW involving narrow gap welding without buttering between the low alloy steel nozzles and the stainless steel safe-ends, and the use of a corrosion resistant weld filler metal (Alloy 52). AREVA performed a thorough characterization of this type of welds, which shows a particular microstructure close to the fusion line between the low alloy steel and the nickel base alloy, where the heat affected zone of the low alloy steel is decarburized. This paper presents results of fracture toughness tests performed with the crack tip located in this area, in the ductile to brittle transition in the as post-welded heat treated condition and after thermal ageing. The results show an excellent fracture toughness behavior of this particular area, compared to that of low alloy steel parent metal.

scholarly journals FORMATION OF THE INFORMATIONAL SUPPORTING FOR MANAGEMENT OF POWER GENERATION AND DELIVERY ON THE COGENERATION POWER PLANT IN THE LIBERALIZED ELECTRICITY MARKET

2021 ◽  
Vol 2021 (2) ◽  
pp. 67-76
Author(s):  
O. Kotsar ◽  
◽  
I. Rasko ◽  
◽  
◽  
...  
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Energy Management ◽  
Power Supply ◽  
Electricity Market ◽  
Power Plants ◽  
Automated System ◽  
Demand Side ◽  
Informational Support ◽  
Successful Solution

The liberalization of the electricity market aims at the most complete repletion of consumer needs for electricity and quality power supply, which requires the adaptive management of an energy using both by demand side and by the electricity producers – power plants. The successful solution of this task provides, in particular, for using the effective methods and reliable means for the formation of the informational support for the tasks of managing the power generation and delivery on the power plants in order to ensure conforming in real time the market power bids to current demand side asks. The article proposes a methodology, describes the implemented tools and analyzes the experience of managing the power generation and delivery on the cogeneration power plant based on the information which formed by the automated system for control, metering and energy management in the conditions of functioning of the liberalized electricity market of Ukraine. References 10, figures 5.

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