钒：改造未来

Nitrogen Strain Aging in Microalloyed Steels

Abstract:

•    The strain aging susceptibility of commercially produced steels can not be predicted from total nitrogen levels.
•    In vanadium microalloyed steels, higher levels of vanadium and nitrogen tend to reduce the risk of strain agmg.
•    The potential for strain aging in a production steel grade are dependent on processing and sampling procedures, in addition to chemistry considerations.
•    Simulating coil cooling of strip samples by reheating to 600°C and furnace cooling is very effective in eliminating strain aging in microalloyed steels, presumably through the complete precipitation of available free nitrogen.
•    Of the available nitride formers, only vanadium provides the additional benefit of increased strength when acting as a scavenger for free nitrogen.
•    To optimize the strengthening affect of vanadium additions and reduce the potential for strain aging, processing of V-N steels should be controlled for maximum precipitation by considering the time at temperature necessary for full precipitation. For strip steels, this means optimizing the coiling temperature, and insming all parts of the coil are exposed to the proper slow cooling time blow 600°C.