Different types of cracks found in coke drums and their likely sources were identified in a metallurgical study done by Penso et al. [
6]. The deepest cracks were found in the heat affected zones of internal welds, while the largest number of cracks was found in the stainless steel clad material. The cracks were attributed to a number of possible sources such as corrosion, stress concentrations caused by weld geometry, cyclic thermal stress, differences in material properties such as coefficient of thermal expansion (CTE) and tensile strength, thermal shock, and heat affected zones around welds. Xia et al. [
7] conducted a finite element analysis of a coke drum for a complete operating cycle. The results showed that the clad material experiences a biaxial stress cycling with a maximum value higher than that of the yield limit of the material. The critical stress value was attributed to bending caused by thermal cycling and differences in CTE between the clad and base materials. The authors suggest that low cycle fatigue is the main failure mechanism of the simulated coke drum, which aligns both with previous studies and the real case. Several studies [
9–
11] have since been conducted in an effort to improve the selection of materials for coke drums. Nikic [
8] used material properties given in ASME Boiler and Pressure Vessel Code and conducted finite element analyses to explore the effect of different clad/base material combinations. Chen [
9] and Rahman [
10] carried out extensive material testing to more accurately characterize the thermal-mechanical material properties of common coke drum materials. In addition, the thermal-mechanical properties of weld material and heat-affected base metals were also experimentally determined [
9].