Effects of substituting W for Mo on mechanical properties, especially on Low Cycle Fatigue behavior in a quenched and tempered Martensitic steel(USS"T-1" Alloy) have been investigated. Tensile property of the alloys were about similar between the two alloys, whereas W containing alloy exhibited excellent impact resistance compared with Mo containing alloy.
Little difference in fatigue behavior was observed between them. Both alloys exhibited cyclic softening behavior under Quenched and Tempered condition.