Evaluation of Low Cycle Fatigue (LCF) in Pre-Welded Nickel Alloy 625 to C - 1/2Mo Explosion Clad Plates DetaClad™ for Coke Drum Applications

Abstract Coke Drum undergoes extreme thermal cycling, alternating between high-temperature coking and rapid quenching phases. This process subjects the materials to significant cyclic thermal stresses, leading to Low Cycle Fatigue (LCF) behavior, which can result in cracking and structural failure, particularly in vulnerable areas. Welds in coke drums are especially prone to LCF-induced damage due to residual stresses from welding, differences in mechanical properties between the weld metal and base material, and potential welding defects [1]. Among cladding technologies, Explosion Welding (EXW) is a reliable and cost-effective solution for applying corrosion-resistant layers onto steel bases. The DetaClad™ [2] process minimizes circumferential welds by producing large cladder plates, reducing fatigue risks and improving operational reliability in coke drum applications. However, producing these larger plates often requires pre-welding smaller corrosion-resistant alloy (CRA) plates, raising concerns about their LCF resistance under severe thermal cycling. This paper presents findings from an LCF testing program on pre-welded Alloy 625 plates explosion-welded to C-1/2 Mo alloy steel. Results demonstrate the plates superior fatigue resistance, validating their durability in demanding coke drum operations.