Nonmetallic Inclusions in Fe–26Mn–10Al–1.2Si–3Cr–3Ni–1.4C–0.1V Induction‐Melted Steel and their Influence on Fracture Under Hot Plastic Deformation

The work represents study of the nonmetallic inclusions formation and their influence on the fracture of induction‐melted Fe–26Mn–10Al–1.2Si–3Cr–3Ni–1.4C–0.1V steel in as‐cast state and under conditions of hot plastic deformation. The microstructure of steel in initial state is investigated, as well as cold and hot fractures. It is shown that the investigated steel has several types of noticeable defects after casting. The first one is represented by small Mn‐rich oxides and eutectic‐like areas, while the other one seems to be Al 2 O 3 films, which leads to microcrack formation. The reason for low deformability is also in a rough columnar grain structure, which points to slow crystallization and impurity movement to the grain boundaries. After 90 min annealing with further rolling from 1050 °C, steel remains prone to hot crack formation. It is mainly caused by initial structure, inclusions, and formation of carbides at the grain boundary, especially in near eutectic areas that contain S and P. XRD investigations show that hot crack surface contains N and C‐rich austenite, iron nitride, as well as Mn and Al oxides with complex Fe–Mn oxides.