Analysis on Cracking Failure of Boiler Superheater Tube Elbow
After a 12Cr1MoVG steel boiler was put into use for several months, it was found that the superheater tube elbow was cracked. The optical microscopy, microhardness tester, scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) were conducted to analyze the cracking failure of bo...
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Department of Materials Protection
2021-10-01
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| Series: | Cailiao Baohu |
| Subjects: | |
| Online Access: | http://www.mat-pro.com/fileup/1001-1560/PDF/20211030.pdf |
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| Summary: | After a 12Cr1MoVG steel boiler was put into use for several months, it was found that the superheater tube elbow was cracked. The optical microscopy, microhardness tester, scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) were conducted to analyze the cracking failure of boiler superheater tube elbow. Results showed that the main reasons for the failure of superheater tube elbow were alkali environmental stress corrosion and hydrogen embrittlement. During the operation of the superheater tube elbow, there was concentrated alkali solution locally. The concentrated alkali solution corroded the inner wall of the tube under the action of high temperature and water and generated a small amount of hydrogen. Under the action of residual stress, the hydrogen invaded into the metal and accumulated at the grain boundaries and then caused hydrogen embrittlement. This was the fundamental reason for the intergranular cracking of the inner wall of elbow. |
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| ISSN: | 1001-1560 |