Abstract: Fracture occurred at both the head and tail ends of a straight pipe section in a pump warming pipeline. The fracture causes of the pipeline section were analyzed by means of macroscopic observation, chemical composition analysis, metallographic examination, hardness testing, scanning electron microscopy and energy dispersive spectroscopy. The results show that uneven corrosion occurred inside the pump warming pipeline during the boiler feedwater process. As the fracture locations were located at the discontinuous parts of the internal structure of the pump warming pipeline, long-term fluid flow disturbance aggravated the corrosion degree at these positions. Eventually, the pipe wall thickness was continuously reduced, the structural strength of the pipeline failed to meet the service requirements, and thus fractures occurred at both ends of the straight pipe section.