Abstract: Investigation has been made on the relationship between microstructure and fatigue property in high strength low-carbon martensitic steel. The results of experiment show that experimental steel has an excellent fatigue strength and a good resistance to fatigue crack propagation when tempered at low temperature. The dominant microstructural feature that contributes to fatigue strength is dislocated martensite matrix and carbides in martensite, whereas for the rate of fatigue crack propagation, the contribution is the orientation difference between adjacent martensite packets, martensite lathes and retained austensite in the form of thin interlath film. The factors affecting deterioration of fatigue behavior in ,tempered martensite embritelement range have also been discussed.

Key words: 马氏体, 疲劳性能, 显微组织（金相学）