The microstructure of K416 B nickel-based superalloy prepared by adjusting the pouring temperature and cooling method were observed and analyzed

and the durability at 975 ℃ and 235 MPa were tested to investigate the influence of pouring temperature and cooling method on microstructure and durability of K416 B alloy. The results indicate that with increasing in the cooling rate

the interdendritic distance of the as-cast alloy can be reduced

and the eutectic structure and the size of γ′ are refined. The large-size eutectic γ′ can be obtained in the as-cast structure of the alloy by sand cooling

which is mainly composed of（γ+γ′） eutectic by single shell cooling. A higher pouring temperature can increase the grain size of as-cast alloy and decrease the size and content of residual eutectic between dendrites

which has little effect on size of γ′. The persistent fracture mechanism of the alloy during stress rupture at 975 ℃ and 235 MPa is dominated by cracks initiation and propagation along the grain boundary

the interface between eutectic and matrix and the interdendritic loose area.Among them

grain size obtained by casting and single shell cooling at 1 550 ℃ is larger

and content of interdendritic eutectic and shrinkage is low with fine and uniform γ′ phase

which is the main reasons for desirable durability.