PAPERS & REPORTS

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

 

Title

Failure analysis of a boiler tube in USC coal power plant

Author

Nam-Hyuck Lee a, Sin Kim b, Byung-Hak Choe c,*, Kee-Bong Yoon d, Dong-il Kwon e

a Dangjin Thermal Power Site Division, Deputy General Manager, East-West Power Co., LTD, Republic of Korea

b Technical Expert Team Power Generation Department, East-West Power Co., LTD, Republic of Korea

c Department of Metal and Material Engineering, Kangnung National University, 123, Ji Byun dong, Kangnung, Gangwon Do 210-702, Republic of Korea

d Department of Mechanical Engineering, Chung-Ang University, Republic of Korea

e Department of Material Science and Engineering, Seoul National University, Republic of Korea

Press and Date of publication

Article history:

Received 21 November 2008

Accepted 7 December 2008

Available online 24 December 2008

Abstract

This paper presents failure analysis of final superheater tube in ultra-supercritical (USC)

coal power plant. Visual inspection was performed to find out the characteristics of fracture

of the as-received material. And the micro-structural changes such as grain growth

and carbide coarsening was examined by scanning electron microscope. Detailed microscopic

studies were made to find out the behavior of the scale exfoliation on the waterside

of tubes. From those investigations, the creep rupture may be caused by the softened structure

induced by carbide coarsening and accelerated by the metal temperature increase by

the impediment of heat transfer due to voids.

_ 2008 Elsevier Ltd. All rights reserved.

Keywords:

Boiler tube

Oxide scale

Overheating

Creep

Thick edge crack