Abstract
AbstractThe solidification microstructure of an Fe–Mn–C–Al high-Mn steel with added Nb was studied by optical microscopy and scanning electron microscopy. The results showed that the size of the columnar and equiaxed grains in the solidified structure of the high-Mn steel without added Nb was large. When Nb was added, the size of the equiaxed and columnar grains in the solidification structure of the high-Mn steel decreased. The twin-induced plasticity in the high-Mn steel with added Nb clearly refined the grain size of the solidified structure and simultaneously increased the equiaxed crystallization rate. The high-melting-point second-phase particles increased the heterogeneous nucleation rate, which was beneficial for grain refinement. A large amount of Nb precipitates from the solidification process increased the equiaxed crystallization rate of the solidified microstructure. The increased crystallization rate affected the growth direction of the columnar and equiaxed grains during solidification and indirectly decreased the probability of crack formation, which improved the quality of the twin-induced plastic steel.
Highlights
The solidification microstructure of an Fe–Mn–C–Al high-Mn steel with added Nb was studied by optical microscopy and scanning electron microscopy
The research shows that the addition of niobium to the high-Mn twinninginduced plasticity (TWIP) steel can play a role in grain refinement and crack reduction and provide reference for producing the high-quality TWIP steel
When the Nb content was increased (Figure 2(d)), the grain size of the TWIP steel was further reduced and the average size was only 1.25 mm. These results show that Nb strongly influenced the grain refinement
Summary
Abstract: The solidification microstructure of an Fe–Mn–C–Al high-Mn steel with added Nb was studied by optical microscopy and scanning electron microscopy. The results showed that the size of the columnar and equiaxed grains in the solidified structure of the high-Mn steel without added Nb was large. When Nb was added, the size of the equiaxed and columnar grains in the solidification structure of the high-Mn steel decreased. The twin-induced plasticity in the high-Mn steel with added Nb clearly refined the grain size of the solidified structure and simultaneously increased the equiaxed crystallization rate. The increased crystallization rate affected the growth direction of the columnar and equiaxed grains during solidification and indirectly decreased the probability of crack formation, which improved the quality of the twin-induced plastic steel. The nonmetallic inclusions distribute into a network, whereas molten steel solidifies, which increases the brittleness of the material and tends to break the casting during the solidification process. The research shows that the addition of niobium to the high-Mn TWIP steel can play a role in grain refinement and crack reduction and provide reference for producing the high-quality TWIP steel
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