Microstructure and properties of P91 steel pipeline in abnormal low hardness parts

doi:10.13251/j.issn.0254-6051.2020.03.001

Abstract

Abstract:

The causes of abnormal low hardness found in some parts of P91 steel main steam pipeline during operation of power plant were analyzed by microstructure observation, short-term mechanical properties test and high temperature creep rupture strength test. The results show that the microstructure in low hardness parts of the P91 steel is composed of ferrite and precipitates. The ferrite has a relatively low dislocation density, while the precipitate phases include coarsened M₂₃C₆ phase aggregating at grain boundary, as well as a new precipitated phase of Laves type. Such a microstructure leads to serious reduction of the short-term mechanical properties and high-temperature durability of the P91 steel.

Key words: P91 steel pipeline, low hardness, high temperature creep rupture strength, precipitated phase

CLC Number:

TG142.73

Fan Deliang, Wang Zhiwu, Ju Guangyu. Microstructure and properties of P91 steel pipeline in abnormal low hardness parts[J]. HTM, 2020, 45(3): 1-6.

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