Failure analysis of a superheater pipe based on microstructure/mechanical properties study

Year 2018, Volume: 2 Issue: 2, 29 - 34, 10.01.2019

Reza Bakhtiari , M Ahmadian Abbas Olfati Mohammad Derhambakhsh

Abstract

The fundamental role of superheater pipes in turbines is to produce
superheated steam and direct it to the turbine. These parts are subjected to
damage due to the creep, corrosion and oxidation resulting from combustion
exhaust. In this research, the affecting factors of failure in a plantain
superheater pipe was investigated. Wet chemistry and SEM/EDS analysis were used
to investigate the combustion exhaust deposits and a scanning electron
microscope (SEM) was used to study the fracture surfaces in order to determine
the mechanisms of the fracture. The results showed that exposure of the
superheater pipes at temperatures higher than the standard limits caused
strength reduction and occurrence of plastic deformation. Furthermore, the
combustion exhaust deposits, caused reduction in heat transfer, in addition to
severe corrosion as well as cavity formation due to the presence of hydrogen
were the main reasons of the pipes failure.

Keywords

Combustion deposits, Failure analysis, Superheater pipes, Thermal power plant

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