The exist style of niobium in 0.25% Si non-oriented silicon steel and the interaction mechanism

and the effect of Nb on microstructure and electromagnetic properties in the finished steel are studied. The results show that

for present work

the solution and precipitation of the niobium inclusions and the traditional inclusions can be improved by adding 0.008 3% niobium into the liquid steel. Thus

the average size of inclusions will obviously decrease from 152 nm to 64 nm

and the number of which will sharply increase from 1.7 x 10

7

/mm

3

to 8.4 X 10

7

/mm

3

. Among of which

the main niobium contained is Nb (C

N)

with size being hundreds of nanometer grades. They can pin the grain boundary and decrease the diffusi

on rate of grain boundary significantly

and then resulting the occurrence of the refinement grain size segregating and the island shape grains. Finally

the iron loss and magnetic induction of the finished steel are obviously deteriorated by 0.7 W/kg and 0. 03T

respectively. More over

the deterioration of iron loss and magnetic induction in steel will increase monotonically with increasing niobium content. The Nb inclusions lead to increase of iron loss P

15/50

by deterioration of hysteresis loss.