Corrosion of Type 310 Stainless Steel By Synthetic Fuel Oil Ash^★

In an investigation of the corrosion of Type 310 stainless steel in synthetic fuel oil ash, the minimum temperatures at which the steel was attacked by a mixture of V₂O₅ and Na₂SO₄ and by mixtures of V₂O₅ and NaVO₃ were determined. The minimum temperatures ranged from 1075 F for a mixture of 67 percent V₂O₅ and 33 percent NaVO₃ to 1220 F for a mixture of 88.5 percent V₂O₅ and 11.5 percent NaVO₃. An unidentified phase was produced at the interface between the steel and a vanadium compound or mixtures of compounds in the temperature range 1075 F to 1890 F. There was evidence that this phase penetrated into the steel at grain boundaries. Steel heated above 1700 F in contact with a vanadium compound or a mixture of these contained nodules of an unidentified phase at the grain boundaries. Spectrochemical analyses of the slag (fused synthetic mixture) indicated that it contained some of the components of the steel in the same proportions as they were present in the steel. 4.3.3