Vanadium has an effect on gray iron similar to molybdenum, but the concentration must be limited to less than 0.15 percent if carbides are to be avoided. Even in such small amounts, vanadium has a beneficial effect on the elevated temperature properties of gray iron.

Steel Casting The beneficial effect of relatively small additions of tin (less than 0.10 percent) on the stability of pearlite in gray iron has been reported by Davis et all. The results of extensive use of tin in automotive engines has been reported by Tache and Cage[12]. Its use is particularly helpful in complex castings wherein some sections cool rather slowly through the Ar3 temperature interval. It has been found that additions of up to 0.05 percent antimony have a similar effect. In larger amounts, these elements tend to reduce the toughness and impact strength of gray iron, and good supervision over their use is necessary.

Aluminum Casting Although most gray irons contain some titanium and the effect of titanium on the mechanical properties has been investigated many times, it is only recently that Sissener and Eriksson[13] have reported the effect of titanium reduced from a titanium containing slag in an electric arc furnace. With titanium contents of 0.15 to 0.20 percent, the graphite flakes tend to occur as Type D graphite rather than predominantly Type A, which is generally considered desirable. They found that for irons with carbon equivalent of less than about 3.9 percent, the addition of titanium tends to lower tensile strength. but, for the higher carbon equivalent irons, tensile strength is improved. Increasing the titanium content of gray iron from about 0.05 to 0.14 percent through the use of a titanium bearing pig iron increased the strength of a hypereutectic iron in an ASTM Specification A 48 test bar A (7/8 in. diameter) from 22,000 to 34,000 psi. Further work is being done with titanium additions.

Stainless Steel Casting Normally. nitrogen is not considered as an alloying element and generally occurs in gray iron as a result of having been in the charge materials. Morrogh[14] has reported that at higher nitrogen levels the graphite flakes become shorter and the strength of the iron is improved. Gray irons usually contain between 20 and 92 ppm (0.002 to 0.008 percent) nitrogen. If the nitrogen approaches or exceeds 100 ppm, unsoundness may be experienced if the titanium content is insufficient to combine with the nitrogen.