Failure analysis of type 304H stainless steel welds in RFCC unit
- Toyo Engineering Corp., Narashino, Chiba (Japan)
In residue fluid catalytic cracking (RFCC) unit, type 304H stainless steel is used as a component material of regenerator, separator and flue gas duct operating at as high as 700 C and over. Crackings have occurred in ferrite controlled type 308H stainless steel weld metals made by flux cored arc welding (FCAW) process after approximately one year operation of RFCC unit. In order to find the cause of the failure, metallurgical analysis of cracked welds, and creep tests at 730 C of type 304H stainless steel welded joints prepared by various welding process have been performed. It has been confirmed that the creep strength of welded joint by any welding process is commonly lower than that of base metal. In addition, the possibility of adverse effect of bismuth (Bi) on creep properties, which is added to flux of wire as bismuth oxide to improve slag removability, has been recognized.
- OSTI ID:
- 403563
- Report Number(s):
- CONF-960706--; ISBN 0-7918-1783-0
- Country of Publication:
- United States
- Language:
- English
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