Stainless steel drain tube from a hot-blast stove for the preheating air was premature failure. The main phenomenon was that the wall thickness of the expansion joint of the hotair stove-s air outlet tube was reduced at the failure point，with cracking and punching. It was observed that certain areas occurred through-way cracking in the thinned tube while others showed significant collapsing. A fracture taken from cracking areas was analyzed by SEM and was found to have a mixture of intergranular and transgranular cracking. Metallographic examination and chemical analysis of two specimens, also from the failed region, revealed the presence of large grain with widened grain boundary and wedge-type cavities at grain-boundary triple points, which were caused by operating temperature exceed those intended for this steel and may be promoted by grain-boundary precipitates. Failure of the tube was attributed to creep-type rupture at high-temperature conditions resulting from prolonged overheating and to thinning of the way by high-temperature corrosion and oxidation to the point at which the hot-air pressure in the tube and eventually lead to overload failure of the hot air pipe.