Abstract: Influences by different temperatures on hot ductility of Inconel 600 alloy for heat exchanger service are studied.The results show that the alloy exhibits good hot ductility within the temperature range of 1 075~1 200℃, which is proved by the facts as described as follows.Obvious necking is observed at tensile fractures, which means a plastic fracture;the percentage reduction of area is above 90%, and reaches the maximum at 1 150℃;along with rising of the temperature, the necking phenomenon is getting more and more obvious, while more and more dimples are developed at the fracture, which means that the plasticity becomes better and better;when the temperature rises to 1 150℃, the fracture necking becomes the largest, and the dimple quantity gets to the maximum, and the dimple depth is also gets to the maximum;when the temperature rises to 1 175℃, the dimple quantity begins to be reduced, and likely, the thermal plasticity begins to drop;and when the temperature reaches 1 200℃, the tensile fracture is smooth, and free of any dimple, while grain boundary oxidation and local grain drop phenomenon are observed;the recrystallized grain quantity gradually increases along with increase of the deformation temperature within the range of 950~1 200℃;finally when the temperature reaches 1 050℃, the grains are basically of fine equiaxed crystals as evenly distributed, and complete dynamic recrystallization occurs with the alloy.