Abstract:
Mg treatment was chosen to modify the inclusions, microstructure, and properties of M7 high-speed steel under pressure. The results showed that Mg can effectively improve the cleanliness of steel, as the content of T.O, S, and N decreased gradually as Mg content increased. And, while the proportion of large-size inclusions decreased significantly, the proportion of small-size inclusions increased gradually. In addition, the type of inclusions in steel changed along the regular Al2O3 -> MgO center dot Al2O3 -> MgO, MnS -> MgS, and these two changes were carried out at the same time. Mg treatment can also significantly refine the grain size and dendrite. The network structure of carbides in steel was broken, and the segregation phenomenon was obviously weakened. Finally, both the plasticity and impact toughness of the experimental steel have been improved.
