Investigation was performed on the effects of degree of restraint on thermal fatigue life of steels. Relations between strain amplitude, stress amplitude and cycles to failure were confirmed, using Coffin type thermal fatigue testing apparatus for some cast steels and 18Cr 8Ni stainless steel. Based on these relations then, the effects of restraint on thermal fatigue life and on some other factors were calculated.
The results indicate that, although the alleviation of restraint is effective to prolong the thermal fatigue life, the degree of the effects varies remarkably according to the kind of materials and the amount of strain amplitude.
