Effect by Ti on Thermal Fatigue Resistance and Oxidation Resistance of Cr35Ni5 Guide Plate

Investigated is the effect by Ti content on thermal fatigue resistance and oxidation resistance of the Cr35Ni5 guide plate.As a result it is identified that along with increase of the temperature,the number of the cold and hot circulation cycles as experienced by the specimens with different Ti contents are reduced,when cracks occurring on their surfaces.During the thermal fatigue test to the 0.9%Ti specimen as made at 600℃,cracks occurred after 10 hot and cold cycles.Compared with the specimen without Ti,the thermal fatigue resistance is doubled;and during oxidation test to the 0.9%Ti specimen as made at 900℃,after 50 hours of oxidation,the specimen weights 1.6 mg more via oxidation.Compared with the specimen without Ti,the post-oxidation weight is lessened by 0.7 mg,and the oxide film becomes denser.Adding an appropriate amount of Ti to the Cr35Ni5 material,Ti and C form TiC,and TiC is formed at a higher temperature,and is preferentially formed in the melt.It serves as a heterogeneous carbide nucleation base,and thus increases the nucleation rate,thereby refining the primary carbides,and then improving the structure,so as to eventually improve the heat fatigue resistance and oxidation resistance of the guide plate.