Life assessment of 12Cr1MoV steel for high temperature superheater after long-term service

doi:10.13251/j.issn.0254-6051.2021.07.043

Abstract

Abstract: Microstructure, chemical composition and mechanical properties of the 12Cr1MoV steel sampled from the high temperature superheater after long-term service were analyzed by means of metallographic observation, scanning electron microscope, hardness and tensile property tests. The results show that after long-term service at high temperature, some sampling tubes have seriously degraded microstructure, with the grade of pearlite spheroidization being 4.5, the carbides being clustered in chains, and have creep holes and intergranular cracks. And the more serious the microstructure deterioration is, the lower the hardness and the tensile strength are, and the worse the comprehensive mechanical properties are. On the other hand, the thickness of inner oxide layer has nothing to do with the degree of microstructure deterioration. The equivalent temperature of the sampling tubes during operation is close to the upper limit temperature stipulated by the material, and the residual creep life of the sampling tubes is more than 40 000 h.

Key words: high temperature superheater, 12Cr1MoV steel, microstructure, mechanical properties

CLC Number:

TG142.7

Song Yu, Guo Yan, Li Penggang, Yang Wentao. Life assessment of 12Cr1MoV steel for high temperature superheater after long-term service[J]. Heat Treatment of Metals, 2021, 46(7): 223-228.

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