A catastrophic furnace roll failure was observed in a continuous hot dip line. The failure occurred in the weld joining an end bell to a roll shell and resulted in the complete separation of the end bell from the roll shell. The roll had been in service for approximately 7 months before failure. Typically, rolls in this furnace roll position have a short life, less than 1 year. The roll shell and the end bell were made of high-temperature alloy. The journal was made of stainless steel. Inconel welding electrode was used as the weld filler material. The roll shell and the end bells were shrink fitted before welding. The welding process was flux-cored arc welding (FCAW). Upon completion of welding post-weld heat treatment (PWHT) was applied for 3 hours at 1093°C to the entire roll. To extend the roll life, a new design and a new welding method, electron beam welding (EBW) without filler metal, were proposed. To evaluate the effectiveness of the new design and the new welding process, four kinds of numerical analyses were conducted on the new design for both FCAW and EBW which included a weld residual stress analysis, a PWHT analysis, a heat transfer analysis, and a creep-fatigue analysis. Analysis results showed that the new design with EBW has lower stress and creep strain than with FCAW, which could improve the roll creep-fatigue life.

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