Prediction models for vanadium precipitation strengthening of ferritic steels have been available and used over the course of many years of vanadium microalloying experience. The basis and origin of a newly revised but proven strength prediction model is reviewed and explained. Inherent in the accuracy of the model is the requirement for the assessment of the available carbon and nitrogen to form V(C,N) precipitates. This paper discusses various situations where the amount of nitrogen and carbon in the ferrite may vary substantially, and how the availability of these elements can be significantly altered by the time of precipitation and the presence of other alloy elements, particularly Ti, Nb, and Al. Of these, the effect of the Al content (and prior processing history) seem to be most widely overlooked when evaluating and predicting the expected strengthening of the VN precipitate in polygonal ferrite.
Vanadium, Precipitation, Yield Strength, Nitrogen
Robert J Glodowski
Evraz – East Metals (NA), Chicago, Il, 60601 USA
Vanadium Microalloyed Steels: A Symposium in Memory of Michael Korchynsky, MS&T14, 12-16 October 2014, Pittburgh, PA, USA