DBPapers
DOI: 10.5593/sgem2012/s12.v3006

INVESTIGATION OF THE MICROSTRUCTURE DEGRADATIONS IN FERRITIC STEELS AND THEIR IMPACT ON THE CREATION OF CRACKS IN THE PIPES SYSTEM OF POWER PLANTS

M. RAMA, R. MAKSUTI
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 3, 481 - 486 pp

ABSTRACT

The goal of this research is the analysis of the microstructure degradations of the pipes
system in power plants of Kosovo, during production process of electricity. For this
purpose were investigated possible changes in microstructure of the ferritic steels, type:
15Mo3 (1.5415) and 13CrMo4 (1.7335), which is mechanically stable in high
temperature and pressure of working conditions. Samples were taken from different
positions and quote at the power plants A and B of KEK, and were observed with light
microscope. From the digital photos was determined thickness of corroded layer. Cracks
in pipe walls were detected using ultrasonic method and penetrating solutions. In
internal side of pipe walls was found a small amount of iron oxide deposits, and
damages in form of crater as a result of corrosion impact. Damages on the internal side
of pipe are due the action (presents) of oxygen and probably chlorine. Under impact of
oxygen presents in water are create (formed) iron oxide (Fe2O3 created over 2000C,
while over 4000C created Fe3O4). Based on results obtained during the investigation of
corrosion in pipes system of KEK it is found that microstructure degradations were
influenced from stress corrosion and hydrogen embrittlement.

Keywords: power plants, microstructure, degradation, pipe, stress corrosion