This is a comparative analysis of microdamage by creep pores in the metal of steam pipes following prolonged high-(540 -560°C) and low-temperature (512 -530°C) operation. Microdamage at low temperatures is found to take place at considerably lower levels of equivalent stress than at high temperatures. Reducing the operating temperature after the onset of pore formation is not an effective way of enhancing the reliability and durability of bends.