scholarly journals The use of the potential drop technique for creep damage monitoring and end of life warning for high temperature components

2017 ◽  
Vol 34 (5-6) ◽  
pp. 458-465 ◽  
Author(s):  
A. Wojcik ◽  
M. Waitt ◽  
A. S. Santos
Keyword(s):  
High Temperature ◽  
End Of Life ◽  
Creep Damage ◽  
Potential Drop ◽  
Damage Monitoring ◽  
High Temperature Components ◽  
Drop Technique

Assessing the Condition and Estimating the Remaining Lives of Pressure Components in a Methanol Plant Reformer: Part 1 — NDE

2016 ◽  
Author(s):  
Brian E. Shannon ◽  
Carl E. Jaske ◽  
Gustavo Miranda
Keyword(s):  
High Temperature ◽  
Creep Damage ◽  
Sensor Technology ◽  
Special Focus ◽  
Laser Measurements ◽  
Typical Data ◽  
Multiple Sensor ◽  
High Temperature Components ◽  
Inspection Techniques ◽  
Non Destructive

Statoil Tjelbergodden operates a 2,400 ton/day methanol plant in Norway. In order to assess the condition and reliability of high temperature components within the reformer, a series of advanced non-destructive examination (NDE) technologies were applied to radiant catalyst tubes, outlet pigtails, and outlet collection headers. The inspection techniques were selected and developed to provide data that could easily be used in the engineering assessment of the high-temperature components. Special focus was given to detecting and quantifying high-temperature creep damage. This paper describes the NDE techniques that were employed and provides examples of typical data obtained by using the techniques. Catalyst tubes were inspected using the H SCAN® (Figure 1) multiple sensor technology. This technique utilizes two types of ultrasonic sensors, eddy current sensors, laser measurements, and elevation location sensors in scanning each catalyst tube. The H SCAN® P-CAT™ (Figure 2) technique is applied to outlet pigtails, while the H SCAN® H-CAT™ (Figure 3) technique is applied to outlet headers.

Interpretation of damage mechanics behaviour of two-bar structures for the life extension of high-temperature components

2003 ◽  
Vol 38 (2) ◽  
pp. 125-132 ◽  
Author(s):  
S-T Tu ◽  
X Ling
Keyword(s):  
High Temperature ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Life Extension ◽  
Continuum Damage ◽  
Basic Model ◽  
Different Dimensions ◽  
Damage Theory ◽  
High Temperature Components

The creep damage behaviour of two-bar structures of different dimensions and materials is studied in terms of continuum damage theory. The basic model is used to interpret the effectiveness of life extension measures for complicated structures. It is found that replacement of the more damaged component prior to rupture will result in an optimized life extension efficiency, depending on the geometric or material difference between the damaged and less damaged components. This has potential to provide guidance on the effectiveness of life extension repairs in high-temperature plants.

Continuous Creep Damage Monitoring Using a Novel Potential Drop Technique

2011 ◽  
Author(s):  
Catrin M. Davies ◽  
Peter Nagy ◽  
Aditya Narayanan ◽  
Peter Cawley
Keyword(s):  
Creep Strain ◽  
Low Frequency ◽  
Creep Damage ◽  
Potential Drop ◽  
In Situ Monitoring ◽  
Creep Tests ◽  
Damage Monitoring ◽  
Accelerated Creep ◽  
Resistivity Variation

A new directional low-frequency Alternating Current Potential Drop (ACPD) technique has been developed for continuous in-situ monitoring of creep strain and damage in alloys. The sensor relies on a modified ACPD technique that measures simultaneously both values of resistance in the axial and lateral directions using a square electrode configuration. The technique monitors the variation in the ratio of the measured axial and lateral resistances, therefore can efficiently separate the mostly isotropic common part of the resistivity variation caused by reversible temperature variations from the mostly anisotropic differential part caused by direct geometrical and indirect material effects of creep. Initially, this ratio can be considered proportional to the axial creep strain, while at later stages, the resistance ratio accelerates due to the formation of directional discontinuities such as preferentially oriented grain boundary cavities and micro-cracking in the material. This ACPD technique has been applied to a series of accelerated creep tests on 2.25CrMoV Steel at 650 °C. The results are presented and the application of the method for online component monitoring is discussed.

Quantification of Creep Cavity Evolution Using a Novel Replica Image Processing Technique

2012 ◽  
Author(s):  
Haoliang Yang ◽  
Catrin M. Davies ◽  
John P. Dear
Keyword(s):  
Image Processing ◽  
Creep Damage ◽  
Potential Drop ◽  
Surface Damage ◽  
Practical Method ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Creep Cavitation ◽  
High Temperature Components ◽  
Replication Technique

In industry, the surface replication technique is employed as a practical method for the lifetime assessment of high temperature components. However, the method is limited as it is a time consuming processes, is susceptible to subjective interpretations and is only sensitive to surface damage, whereas creep damage often initiates sub-surface. A replica of a component’s surface is made by applying a softened plastic foil to it. This foil moulds itself to the alloy’s surface when pressed. After its removal from the alloy, the plastic replica provides an exact copy of the etched surface’s microstructure, which can then be examined. A new image processing technique has been developed that provides a reliable and repeatable, quantified measure of creep cavitation using images obtained from replica films. A series of interrupted tests have been performed at the same load on 2.25CrMo (P22) ferritic steel at 650 °C. Post testing, samples were prepared and replication performed. A quantitative 2D map of the cavities across the specimens’ surface has been obtained using a novel image processing technique. The results are related to the specimens’ strain measurements using a displacement gauge and a novel potential drop technique. This new image processing technique may provide a valuable tool for industry.

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.

Potential Drop Strain Sensor for Creep Monitoring

2014 ◽  
Author(s):  
Joseph Corcoran ◽  
Catrin Davies ◽  
Peter Nagy ◽  
Peter Cawley
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Potential Drop ◽  
Damage Mechanism ◽  
Strain Measurements ◽  
Monitoring Technique ◽  
Temperature Damage ◽  
Inspection Techniques ◽  
Creep Monitoring ◽  
Drop Technique

Creep is a high temperature damage mechanism of interest to the power industry and at present lacks a satisfactory monitoring technique. Existing material inspection techniques are extremely laborious while strain measurements rely on often infrequent off-load measurements. A quasi-DC directional potential drop technique is presented that is shown at both room temperature and at high temperature to act as a robust strain gauge. Resistivity changes that are expected to occur in high temperature environments are also discussed as a source of potential error in strain measurements.

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