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Indexed by:会议论文

Date of Publication:2010-01-01

Included Journals:CPCI-S

Volume:4

Page Number:38-42

Key Words:Incoloy800H; down pigtail tube; creep; carburization; failure analysis

Abstract:This article presents failure investigation on the down pigtail tube of hydrogen reburners from Petrochemical Corporation, which leaked many times in two years of service. The tests of Chemical component, Micro-Metallographic structure, EMP and SEM were carried out. The results showed that the fundamental cause for the creep rupture failure resulting in the leakages was the serious carburization at the inner surface of the down pigtail tube. The layer of intergranular corrosion at the inner surface which made the carburization easier accelerated the corrosion speed. The growth of the corrosion layer reduced the effective load thickness of the down pigtail tube and finally made the tube creped until leakage under the work pressure. Moreover, the low content of titanium in the tube reduced the number of Y' [Ni(3) (Al, Ti)], which also had negative effects on the high temperature creep rupture strength.