Titanium inoculation has been shown to be capable of refining the as cast structure of AISI 4335 steel. This refinement consists of changing axed grains and reducing the spacing of the secondary dendrite arms. the structure from columnar to equi-When this steel is heat treated to high strength levels (250,000 psi tensile strength) by conventional quenching and tempering, the refined structure exhibits improved tensile ductility compared to the base or unrefined steel. The amount of improvement varies considerably with the solidification rate, sulfur level, and specimen orientation. In some cases, the reduction in area of the refined steel is nearly twice that of unrefined steel for similar conditions of melting, analysis, and specimen location.