Analysis of Failure Causes of 0Cr19Ni9 Blade Crack
Keywords:corrosion cracking, intergranular corrosion, Cr23C6, blades
In this paper, fracture morphology observation, microstructure analysis, standard corrosion test, and other experimental methods are used to analyze the causes of corrosion and cracking of steam turbine blades (0Cr19Ni9) produced by a certain company. The results showed that cracks appeared during the operation of the blade. A large number of dimples were observed under the scanning electron microscope, almost all of which were shear dimples; at the same time, fatigue bands were also distributed in them. The internal cause of the cracks is the long-term service, which causes the carbon and the alloy to undergo a diffusion reaction to form carbon-rich areas and carbides. They are thermally corroded in the service environment, and the carbon-rich zone is reduced, which reduces the strength of the zone; carbides accumulate at the grain boundary, causing groove-shaped defects at the grain boundary to form a cutting effect. It is easy to form a source of fatigue cracks. The external cause is that the material is subjected to transverse stress for a long time during operation, which leads to the generation of cracks. This article analyzes the failure causes of the blade and proposes related solutions, which have important reference value for production practice.
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