This paper presents the results of an investigation into the failure of steel tubes in a super heater boiler used at one of Kuwait Electrical and Power plant. The material of the tubes has suffered localized overheating, probably as a result of local heat nux impingement phenomenon, caused by gas or oil burners. This phenomenon gave rise to a rapid steam formation causing steam blanketing. It also prevented the accessibility of the water to the tube materials and consequently local, prolong, overheating took place, in which the temperature rose up to 700 degrees C in a frequent manner for long time. The investigation has indicated that the failure attributed to the formation of thick scale of magnetite at the inner surface of the tube wall. The increase of the temperature is clearly shown in the microstructure of the tube at the stress rupture site, where ferrite matrix with spheroidized carbide particles were presented rather than only ferrite matrix with pearlites structure. Consequently, the properties of the materials of the tube have changed from its original values with respect to the design values of the tube due to the effect of the localized prolong overheating. Therefore, the original design values are no longer valid and the materials of the tube failed in a premature manner. at less than 250,000 hours.