Process Industries - Materials Applications and Experiences

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The Materials Applications and Experiences (Process Industries) Technical Community of Interest is a group of people (both AMPP members and nonmembers) who have come together for the purpose of furthering a common cause by sharing wisdom, knowledge, information, and/or data  for exchanging and compiling information on the experience of various metallic materials as related to properties, corrosion resistance, fabrication, weldability, repair techniques, and application in various process environments.
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Weld Filler Metal/Rod ER 16-8-2 vs. ER 308H in a High Temperature SO2-SO3-Air Process

  • 1.  Weld Filler Metal/Rod ER 16-8-2 vs. ER 308H in a High Temperature SO2-SO3-Air Process

    Posted 06-22-2022 05:40 PM
    I would appreciate your thoughts and/or experiences about using weld filler/rod ER 16-8-2, containing 16% (typical) chromium content, vs. ER308H (with ~ 20% (typical ) chromium content in a high-temperature SO2/SO3/Air process at 625C/1157F, to join type 304H stainless steel plate/piping.

      Our goal in considering ER 16-8-2 filler rod is to achieve adequate corrosion resistance to the process, and improved creep strength, and resistance to sigma phase formation, stress relaxation cracking (SRC), and grain boundary carbide precipitation.    

    As you may know, credible corrosion literature, Process Industries Material textbooks/resources, and much experience support recommend using alloys/filler metals with a minimum 18 to 20% chromium content for high-temperature SO2/SO3/air processes.   Note: Photographs from service -exposed 304H plate/ER308H weld  in this application showed an apparent thick red/brown-colored corrosion product scale and scale spalling, but no UT thickness information has yet been obtained.   Should I be concerned about potential weld metal corrosion rates (i.e. > 20 MPY) if we use ER 16-8-2 filler rod in this application?


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    William L. (Bill) Valerioti
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