Analysis on Early Stage Failure of Welded T23 Steel Waterwall in USC Tower Boilers

doi:10.11930/j.issn.1004-9649.2014.12.21.6

Abstract

Abstract: The statistical analysis on causes of early stage failure of T23 steel waterwall in USC tower boilers is conducted. Macroscopic and microscopic examinations on the typical failured specimens are performed and the mechanical properties of the welded joints are tested to determine the mechanism and main factors for the failures. The results show that the failure are due to the traversing cracking occurred in the butt weld of pipes and propagated along its grain boundaries, which is regarded as wedge creep cracking. The high hardness of the weld is the internal cause for wedge creep cracking. The great tensile stress prodcued by the horizontal shrinking of dense fin welds in the waterwall, is the mechanical reason for the cracking formation and extension. Therefore, reducing the hardness and grain size of weld are helpful to aviod cracking.

Key words: supercritical unit, USC tower boiler, waterwall, T23 steel, welded joint, failure

CLC Number:

TK223.3

WANG Xue, LI Xi-qiang, YANG Chao, GE Zhao-xiang, YANG Xian-biao, REN Yao-yao. Analysis on Early Stage Failure of Welded T23 Steel Waterwall in USC Tower Boilers[J]. Electric Power, 2014, 47(12): 21-27.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.2014.12.21.6

https://www.electricpower.com.cn/EN/Y2014/V47/I12/21

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