Assessment of operating limits for critical dissimilar metal welds in a hydrocracker
conference paper
The risk of failure of ferritic alloy steel to austenitic stainless steel dissimilar metal butt-welds in a refinery hydroprocessing unit increases with operating temperature and shutdown cooling rate due to the
combined effects of hydrogen diffusion and thermal fatigue. Operating limits of this type of weld were assessed with finite element modeling and simulation tests, and the findings from this work were supported by plant inspection results. As a result, both the maximum operating temperature and cooling rate constraints were relaxed for critical equipment and piping in a hydrocracker unit. Keywords: Hydrocracker, hydroprocessing, dissimilar metal welds, disbonding, cooling rate, thermal fatigue, finite element analysis
combined effects of hydrogen diffusion and thermal fatigue. Operating limits of this type of weld were assessed with finite element modeling and simulation tests, and the findings from this work were supported by plant inspection results. As a result, both the maximum operating temperature and cooling rate constraints were relaxed for critical equipment and piping in a hydrocracker unit. Keywords: Hydrocracker, hydroprocessing, dissimilar metal welds, disbonding, cooling rate, thermal fatigue, finite element analysis
Topics
TNO Identifier
953558
ISSN
03614409
Publisher
National Assoc. of Corrosion Engineers International
Article nr.
01532
Source title
NACE - International Corrosion Conference Series, Corrosion 2001, 11 March 2001 through 16 March 2001
Files
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