Criteria for calculating low cycle fatigue strength of DZ22 superalloy under complex stress condition are considered.The fatigue life of the material under complex stresses can be predicted according to the criteria

provided its straight axial strengths and any straight axial S—N curve are available.For DZ22 as a kind of directionally solidified high temperature alloy

the low cycle fatigue comparative tests have been made between the uniaxial tension compression and tension torsion at 850℃ and show that the results of tests and calculations are in good agreement.