Degradation Evaluation of 2.25Cr-1Mo Steel Using Nondestructive Method

2005 ◽  
Vol 297-300 ◽  
pp. 1951-1957
Author(s):  
Jong Seo Park ◽  
Un Bong Baek ◽  
Jeong Min Kim ◽  
Seung Hoon Nahm ◽  
Bong Young Ahn
Keyword(s):  
Electrical Resistivity ◽  
Ultrasonic Attenuation ◽  
Indentation Test ◽  
Creep Damage ◽  
Nondestructive Method ◽  
Magnetic Characteristics ◽  
Isothermal Heat Treatment ◽  
Material Degradation ◽  
Aging Parameter ◽  
Degradation Evaluation

Several nondestructive evaluation methods were attempted for the estimation of the creep damage of degraded 2.25Cr-1Mo steel. The specimens of three different aging periods were prepared by an isothermal heat treatment at 430°C, 482°C, and 515°C. The effect of probe configuration on the electrical resistivity was studied. Single configuration method and dual-configuration method were utilized for measuring electrical resistivity. The electrical resistivity was determined by a standard DC four-point probe method at 24±0.5°C. Indentation test, magnetic characteristics test and ultrasonic test were carried out to investigate the correlation between the major characteristics and aging parameter. Unlike the electrical resistivity characteristics, ultrasonic attenuation coefficient and indentation characteristics did not show a relation to Larson-Miller parameter. However, a correlation between the electrical resistivity and aging parameter was identified, which allows one to estimate the extent of material degradation.

The Application of Nondestructive Methods for Degradation Evaluation of Modified 9Cr-1Mo Steel

2006 ◽  
Vol 321-323 ◽  
pp. 528-531
Author(s):  
Jong Seo Park ◽  
Un Bong Baek ◽  
Seung Hoon Nahm ◽  
Sang In Han ◽  
Song Chun Choi
Keyword(s):  
Heat Treatment ◽  
Ultrasonic Velocity ◽  
Treatment Time ◽  
Creep Damage ◽  
Isothermal Heat Treatment ◽  
Material Degradation ◽  
Immersion Method ◽  
Aging Parameter ◽  
Destructive Methods ◽  
Degradation Evaluation

The nondestructive evaluation technique for the material degradation is necessary because of the limitation of conventional destructive methods. In this study, an ultrasonic velocity measurement method was attempted for the estimation of the creep damage of degraded modified 9Cr-1Mo steel. The specimens with seven different kinds of aging periods were prepared by an isothermal heat treatment at 690 . The ultrasonic velocity was measured by an immersion method. The correlation between the measured ultrasonic velocity and tensile properties were studied. The ultrasonic velocity has an declining tendency with the increase of heat treatment time. A correlation between the ultrasonic velocity and aging parameter were established, which allows one to estimate the material degradation of modified 9Cr-1Mo steel.

A CORRELATION BETWEEN THE AGING PARAMETER AND ELECTRICAL RESISTIVITY FOR THE DEGRADED 9 CR STEEL

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2441-2446 ◽  
Author(s):  
UN BONG BAEK ◽  
YUN-HEE LEE ◽  
HO JUN NA ◽  
SEUNG HOON NAHM ◽  
YOUNG HYUN NAM
Keyword(s):  
Electrical Resistivity ◽  
Creep Damage ◽  
Isothermal Heat Treatment ◽  
Material Degradation ◽  
Resistivity Method ◽  
Non Destructive Evaluation ◽  
Electrical Resistivity Method ◽  
Properties Of Materials ◽  
Aging Parameter ◽  
Non Destructive

It is advantageous to use a non-destructive evaluation (NDE) method to assess the mechanical properties of materials since conventional methods are time-consuming and usually require sampling from the material or component. In this study, an electrical resistivity method was attempted for the estimation of the creep damage of degraded 9 Cr steel. The specimens with six different kinds of aging periods were prepared by an isothermal heat treatment at 690 °C. The electrical resistivity was determined by a standard DC four-point probe method at 24±0.5 °C. The home-made probe station and Burster 2304 were utilized for the resistance measurement. A correlation between the measured electrical resistivity and the tensile properties was studied. The electrical resistivity showed a declining tendency with the increase of aging time because the electrical resistivity is strongly dependent on the microstructural changes. A correlation between the electrical resistivity and aging parameter was established, which allows one to estimate the material degradation of 9 Cr steel.

Degradation Evaluation of HK-40 Steel Using Electrical Resistivity

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1615-1620 ◽  
Author(s):  
Seung Hoon Nahm ◽  
Kwang Min Yu ◽  
Jong Seo Park ◽  
Young Hyun Nam ◽  
Sang In Han ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Material Properties ◽  
Room Temperature ◽  
Creep Damage ◽  
Tube Steel ◽  
Isothermal Heat Treatment ◽  
Resistivity Method ◽  
Electrical Resistivity Method ◽  
Heater Tube ◽  
Degradation Evaluation

More effective nondestructive technology for the estimation on material properties has been sought. In this research, a new electrical resistivity method was attempted for the estimation of the creep damage of a degraded heater tube steel. HK40 steel specimens with five different periods of aging were prepared by an isothermal heat treatment at 1050°C and the electrical resistivity was determined by a standard DC four-point probe method. The electrical resistivity at room temperature monotonously decreased with the extent of degradation of the material. It was also observed that Vickers hardness was correlated with the electrical resistivity. The microstructural changes of material during aging was examined by microscope.

Ultrasonic Creep Damage Detection by Frequency Analysis for Boiler Piping

2006 ◽  
Vol 129 (4) ◽  
pp. 713-718 ◽  
Author(s):  
Hiroaki Hatanaka ◽  
Nobukazu Ido ◽  
Takuya Ito ◽  
Ryota Uemichi ◽  
Minoru Tagami ◽  
...  
Keyword(s):  
Power Generation ◽  
High Temperature ◽  
Damage Detection ◽  
Fossil Fuel ◽  
Creep Damage ◽  
High Energy ◽  
Assessment Method ◽  
Nondestructive Method ◽  
Fuel Combustion ◽  
Fossil Fuel Combustion

Boiler piping of fossil-fuel combustion power generation plants are exposed to high-temperature and high-pressure environments, and failure of high-energy piping due to creep damage has been a concern. Therefore, a precise creep damage assessment method is needed. This paper proposes a nondestructive method for creep damage detection of piping in fossil-fuel combustion power generation plants by ultrasonic testing. Ultrasonic signals are transformed to signals in a frequency domain by Fourier transform, and a specific frequency band is chosen. To determine the creep damage, the spectrum intensities are calculated. Calculated intensities have a good correlation to life consumption of the weld joints, and this method is able to predict the remaining life of high-temperature piping, which has been already installed.

Degradation Evaluation of 2.25Cr-1Mo Steel Using Nondestructive Method

2005 ◽  
pp. 1951-1957
Author(s):  
Jong Seo Park ◽  
Un Bong Baek ◽  
Jeong Min Kim ◽  
Seung Hoon Nahm ◽  
Bong Young Ahn
Keyword(s):  
Nondestructive Method ◽  
Degradation Evaluation

Ultrasonic Nondestructive Evaluation of the Creep Damaged IN738LC Superalloy

2004 ◽  
Vol 449-452 ◽  
pp. 569-572 ◽  
Author(s):  
Jai Won Byeon ◽  
J.H. Song ◽  
S.I. Kwun
Keyword(s):  
Nondestructive Evaluation ◽  
Ultrasonic Wave ◽  
Linear Correlation ◽  
Ultrasonic Attenuation ◽  
Creep Damage ◽  
Ultrasonic Nondestructive Evaluation ◽  
Microstructural Parameters ◽  
Creep Time ◽  
The Mean ◽  
The Relationship

It was attempted to evaluate nondestructively the creep damaged IN738LC Ni based superalloys with different degree of rafting using ultrasonic wave. Microstructural parameters (length and width of γ' precipitates) and ultrasonic attenuation were measured in order to clarify the relationship between them. Both the mean length of γ' precipitates and the ultrasonic attenuation increased with creep time. Ultrasonic attenuation was found to have a linear correlation with the mean length of γ' precipitates. It is suggested that the ultrasonic attenuation can be used as a potential nondestructive parameter for assessing the degree of creep damage of IN738LC superalloy.

Estimation of Creep-Fatigue Damage Through Indentation Test Method

2011 ◽  
Author(s):  
Raghu V. Prakash
Keyword(s):  
Tensile Properties ◽  
Fatigue Damage ◽  
Indentation Test ◽  
Creep Damage ◽  
Test Method ◽  
Specimen Preparation ◽  
Creep Fatigue ◽  
Critical Components ◽  
The Cost

Creep, creep-fatigue damage is often estimated through in-situ metallography, tensile testing of specimens. However, these methods require specimen preparation which includes specimen extraction from critical components. Automated ball indentation testing has been used as an effective tool to determine the mechanical properties of metallic materials. In this work, the tensile properties of materials subjected to controlled levels of damage in creep, creep-fatigue is studied. It is found that the tensile properties such as yield strength and UTS deteriorates with creep damage, whereas the same specimens show an improved UTS values (at the cost of ductility) when subjected to creep-fatigue interactions.

Nondestructive Method for Estimation of Chloride Profiles: Correlation between Electrical Resistivity and Holliday-Empirical Equation

2020 ◽  
Vol 146 (10) ◽  
pp. 04020119
Author(s):  
Carlos Eduardo Tino Balestra ◽  
Thiago Alessi Reichert ◽  
Gustavo Savaris ◽  
Wagner Alessandro Pansera ◽  
Ronaldo A. Medeiros-Junior
Keyword(s):  
Electrical Resistivity ◽  
Empirical Equation ◽  
Nondestructive Method ◽  
Chloride Profiles

Creep Damage Analysis of 9–12% Cr Ferritic Steels by Instrumented Indentation Test

2007 ◽  
Author(s):  
Shin-Ichi Komazaki ◽  
Motoki Nakajima ◽  
Tetsuya Honda ◽  
Yutaka Kohno
Keyword(s):  
Early Stage ◽  
Indentation Test ◽  
Creep Damage ◽  
Turbine Rotor ◽  
Ferritic Steels ◽  
Rotor Steel ◽  
Dispersion Strengthening ◽  
Instrumented Indentation ◽  
Block Boundary ◽  
Instrumented Indentation Test

High Cr ferritic steels have a complex lath martensitic structure consisting of several microstructural units, i.e., fine lath, block, packet and prior austenite grain. Additionally, precipitation, solid-solution and dispersion strengthening mechanisms contribute to their excellent strength. However, it is by no means easy to separate the contributions of such strengthening factors and quantitatively understand them because of the extremely fine and complicated microstructure. In this study, the instrumented indentation test was carried out to clarify the change in contribution of each microstructural factor, particularly, “block” during creep. The material used in this study was turbine rotor steel (Fe-10Cr-1Mo-1W-VNbN). The indentation test was applied to the as-tempered and the creep damaged specimens under a wide variety of maximum loads. The test results revealed that the decrease in contribution of block grain was the predominant factor of the decrease in macroscopic hardness at the early stage of creep life. On the other hand, during the second half of the life, the decrease in macroscopic hardness was mainly caused by the decrease in matrix hardness. The decrease in block’s contribution was attributable to the decrease in the resistance of block boundary to deformation, rather than the coarsening of block grain.

Sign in / Sign up

Export Citation Format

Share Document