GRAIN COARSENING BEHAVIOR OF V-Ti-N MICROALLOYED STEELS

The effects of chemical composition and cooling rate after solidication on the grain coarseningtemperature,T_(GC),of the V-Ti-N microalloyed steels have been investigated.It is shownthat the T_(GC) may be obviously raised by adding even a little Ti to the base steel so as to pre-cipitate a great deal of fine Ti-bearing particles of about 10 nm.The T_(GC) does not increasewith the cooling rate,as it is over a certain critical value.The T_(GC) is insensitive to any varia-tion of N content at simulated cooling condition of 150 mm continuous cast slab.TheT_(GC) may be dropped down about 100℃ by adding 0.33 wt-%Mo to the steels.The sensitivi-ty of T_(GC) to cooling condition relates to the Ti and V contents.