Phase composition of heat-resistant ferritic and austenitic steels precipitation-hardened by intermetallic compounds

1. The main hardening phase in ferritic and austenitic steels alloyed with tungsten and molybdenum was Laves' phase. Depending on the alloying with tungsten or molybdenum, or both together, phases of the following type are formed: Fe2W, Fe2Mo, Fe2(W, Mo). 2. In the ferritic steels investigated a niobium carbonitride was formed in addition to Laves' phase. In the austenitic steels three phases were formed—Laves' phase, niobium carbonitride, and M23CP6 carbide. 3. The maximum amount of Laves' phase in steel 12Kh2MV8FB corresponds to the highest hardness. 4. The highest heat resistance of steel 12Kh2MV8FB resulted from tempering at 725–750°C.