## 1 Introduction  
The increasing energy demand induces continuous development in creating new energy generation systems and enhances the existing ones, making them more robust and reliable. One such technology is steam thermal power plants, which possess a remarkable share in energy production worldwide and contribute to several applications. The boiler is an essential component in a thermal power plant to generate steam, driving the turbine to produce power or direct it to subsystems for subsequent use, such as in the desalination plant and fuel heating systems. The tubes in water tube boilers are subjected to several types of failure [1] caused by stress rupture, waterside and fireside corrosion [2, 3], fatigue [4], erosion [5] and lack of quality control. The main focus of the present work is the stress rupture, particularly in water tubes, caused by the overheating associated with being exposed to high temperatures and pressure that lead to tube failure. These conditions are induced in the short or long term. For example, the former is associated with decreasing cooling rate possibly attributedto complete or partial plugging, sudden shutdown of boiler circulating water pump, the rapid temperature increased during the start-up of the boiler evaporation of water in the liquid section, and the increase in the overall thermal resistance due to deposits accumulation inside the tube. The visual examination of the ruptured wall presents with fish mouth appearance, usually in overheating conditions [6]. Ref. [6] described that the plastic deformation in the rupture area shows deformation with elongated grains in the tube over a period during prolonged heat transfer. Refs. [7; 8] further explained that the impact of the difference in temperature conditions on either side of the tube displays variation in the appearance. It has been reported that the different temperatures on either side of the wall, hot wall (fireside), and cool wall demonstrated microstructural changes, especially more toward the hotter side [7; 8]. Concurring, ref. [9] stated that the fireside wall presented in the trials with partial degradation (spheroidization) of the lamellar structure mainly of iron carbide in pearlite colonies. The lamellar structure indicates the main driving force for change, excessive surface energy, which reduces the internal energy of the tube. Ref. [9] further pointed out that after the rupture of the tube, the rapid cooling causes a change in the structure and formation of bainite. However, Refs. [10; 11] demonstrated that the substantial increase in the temperature lowers the yield stress of the metal. Thus, if the yield stress becomes equal to or less than the hoop stress of a metal tube at high temperature, the tube starts to deform, bulge, and thin [10; 11]. Ref. [9] have studied the short-term overheating failure of a boiler water wall tube and examined the evolution of different microstructures during the failure through visual examination. They have concluded from the microstructure examination that the failure occurred due to overheating above the eutectoid temperature (lower critical temperature) of the tube material. One solution to prevent overheating problems is enhancing the heat transfer through the tube wall to the water. Several researchers enhance the heat transfer by modifying the water tubes' inner surface area or inserting different shapes of obstructions inside tubes to induce more flow turbulence and mixings [12]. Either way, considerable concerns exist regarding these techniques for the possible increasing accumulation rate of deposits inside tubes. Most of the literature paid attention to enhancing the heat transfer through the tubes without considering the adverse effect of the accumulated deposits inside the tube on the thermal-mechanical consequences.