Abstract
The effect of Nb addition on the composition, morphology, quantity, and size of inclusions in Fe-Mn-C-Al steel was studied by SEM, EDS, and thermodynamic analysis. The research shows that the number of inclusions in Fe-Mn-C-Al high manganese steel decreases obviously after adding 0.04% element Nb, and some inclusions in the steel evolve into complex niobium inclusions. When the niobium content increases to 0.08%, the influence of niobium on inclusions in steel becomes more obvious. The precipitation temperature of inclusions in Fe-Mn-C-Al steel was analyzed by thermodynamics. The results show that the nucleation core of the composite inclusions is AlN, and then NbC and MnS precipitate locally on its surface. With the increase of Nb, the amount and volume fraction of NbC inclusions precipitated in steel increase.
Highlights
The results show that AlN was formed first in the liquid phase, and AlN could be used as heterogeneous core to form MnS (Se) inclusions, forming AlN-MnS(Se) complex non-metallic inclusions
It was found that the dominating inclusions in Fe-Mn-C-Al Twinning Induced Plasticity (TWIP) steels are MnS, AlN, MnO, and Al(O)N before adding Nb
Single-phase Nb inclusions and MnS-NbC niobium complex inclusions begin to precipitate in the steel
Summary
Gigacher et al [13,14] analyzed inclusions in as-cast Fe-(15~25) Mn-3Al-3Si TWIP steel by SEM and EDS, and they found that the main types (number ratio) of inclusions in TWIP steel were MnO-Al2 O3 -AlN (40%), MnO-Al2 O3 -MnS (10%), MnO-Al2 O3 -AlN-MnS (30%), and single-phase AlN (14%). Kang et al [19] studied the hot plasticity of TWIP steel and found that AlN precipitated at the austenite grain boundary, which seriously worsened the as-cast thermoplastic of TWIP steel. It is necessary to study and analyze systematically the type, quantity, and distribution of inclusions in Fe-Mn-C-Al TWIP steels with Nb, which is of great significance to the development of the inclusion control theory of twinning-induced plasticity steel
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
