Introduce technical papers and reports of IIT (Instrumented Indentation Technology) and correlated fields.



Safety assessment based on mapping of degraded mechanical properties of materials for power plant pipeline using instrumented indentation technique


Kyung-Woo Lee a,*, Kug-Hwan Kim a, Ju-Young Kim a, Kwang-Ho Kim b, Byung-Hak Choi c, Dongil Kwon a

a Department of Materials Science & Engineering, Seoul National University, Seoul 151-744, Republic of Korea

b Frontics Inc., Research Institute of Advanced Materials, Seoul National University, Seoul 151-744, Republic of Korea

c Department of Metal and Materials Engineering, College of Engineering, Kangnung University, Kangnung, Republic of Korea

Press and Date of publication

Article history:

Received 15 August 2007

Received in revised form

19 August 2008

Accepted 17 September 2008


The remaining life prediction of those is accomplished by accelerated degradation tests such as creep

testing. However, creep testing is both time-consuming and expensive and hence impossible to apply

under industrial conditions, where prompt management and analysis are necessary. While residual

lifetime predictions and safety assessments of power plant facilities are made using standard mechanical

testing methods such as uni-axial tensile and fracture mechanics tests. However, these tests cannot be

applied to in-service structure components because of their destructive nature. A nondestructive

instrumented indentation technique is thus attractive for investigating the mechanical properties of inservice systems. This technique can measure flow properties by analyzing indentation load-depth curves reflecting the deformation behavior of the material beneath the rigid spherical indenter. In this study, heat treatment was used to produce degraded samples of X20CrMo12.1V and SA-213 T23, materials widely used in power plant pipelines, and their mechanical properties versus degree of degradation were evaluated by instrumented indentation. We assess the degradation of mechanical properties by microstructural analysis and discuss the possibility of appraising the safety of power plant facilities by in-situ monitoring of mechanical properties using instrumented indentation testing.

_ 2008 Elsevier Ltd. All rights reserved.


Safety assessment

Instrumented indentation technique

Degraded mechanical properties

Power plant pipelines