A theoretical procedure for detection of simulated cracks in a pipe by the direct current–potential drop technique

2002 ◽  
Vol 216 (1-3) ◽  
pp. 203-211 ◽  
Author(s):  
Wen-Hwa Chen ◽  
Jen-Shiung Chen ◽  
Huei-Lu Fang
Keyword(s):  
Direct Current ◽  
Potential Drop ◽  
Drop Technique ◽  
Theoretical Procedure ◽  
Direct Current Potential Drop ◽  
Current Potential

Application of Potential Drop Technique to the Inspection of Welded Boiler Pressure Parts

2004 ◽  
Author(s):  
Seiichi Hamada ◽  
Yasuki Ogawa ◽  
Hideo Iida ◽  
Tomoki Kuroiwa ◽  
Masahiko Kuroki ◽  
...  
Keyword(s):  
Direct Current ◽  
Electrical Potential ◽  
Creep Damage ◽  
Potential Drop ◽  
Burst Test ◽  
Technical Requirements ◽  
Pulsed Direct Current ◽  
Drop Technique ◽  
Direct Current Potential Drop ◽  
Current Potential

In this paper, a practical method using the electrical potential drop technique was discussed to evaluate the creep damage accumulated in the welded power piping such as main steam pipe and hot reheat pipe. Round robin experimental measurements conducted by the authors et al. as academic activities in the Japanese Society for Non-destructive Inspection showed that the potential drop technique is effective for the application to the inspection of welded boiler pressure parts. The authors have conducted additional experimental and numerical studies for verification focusing on the application of the pulsed direct current potential drop technique. The authors have proposed technical requirements on the potential drop technique for the application to the inspection of welded power piping to be implemented in JSME Codes for Thermal Power Generation Facilities (2003 Edition) as a non-mandatory appendix JA. And the practical on-line measurement in the high temperature and high pressure burst test using the repair-welded power piping has been conducted. In this burst test, Tokyo Electric Power Company has tried to monitor the creep damage accumulated in the seam-welded area using the commercialized tool based on pulsed direct current potential drop technique.

General Rule of Method for Measurement of Thickness and Crack Size by Electric Potential Drop Technique: Outline of the NDIS3426:2008

2009 ◽  
Author(s):  
Yang Ju ◽  
Seiichi Hamada
Keyword(s):  
Fatigue Crack ◽  
Electric Potential ◽  
General Rule ◽  
Potential Drop ◽  
Crack Size ◽  
Pulsed Direct Current ◽  
Measurement Of Thickness ◽  
Drop Technique ◽  
Direct Current Potential Drop ◽  
Current Potential

The Japanese Society for Non-Destructive Inspection (JSNDI) published general rule of method for measurement of thickness and crack size by Electric Potential Drop Technique as the Standard of JSNDI (NDIS3426) in January, 2008. NDIS3426 was established based on the researches for many years including the round robin tests conducted as the academic activities in JSNDI, and the previous technical guideline and standard ASTM E-647-05 ANNEX A6 and BS ISO 12108:2002 established for the measurement of fatigue crack growth in specimens. In this paper, the outline and the background of NDIS3426 was described. The electric potential drop technique is one of the promising methods to monitor or measure the thickness and crack size for the practical use in many industries. For the inspection of the surface deep fatigue crack in the steam turbine casing, the advanced crack depth indicator based on the potential drop technique has been applied. For the monitoring the creep damage accumulated in the seam-welded power piping, the commercialized tool based on the pulsed direct current potential drop technique has been used. For the pipe wall thinning measurement in the operating thermal power plant, the pulsed direct current potential drop technique was applied. This paper shows the present condition of the practical use and the future prospect of the potential drop technique.

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