Effect of boron on the distribution and amounts of carbide phases in austenitic steel

1. Boron affects the amount, size, and distribution of the principal phases in heat resistant austenitic steel 1Kh14N18V2B-NbC and M23C6 carbides. 2. With up to 0.017% B the particles of NbC coalesce. The NbC stringers are replaced with coalesced spheroidal particles of NbC. 3. Boron reduces the amount of M23C6 precipitated during aging. 4. Boron forms borides, and eutectic at high temperatures (1300°C). The amount and composition of the borides and the eutectic depends on the boron content. With up to 0.017% B, boride phase of the M3B2 type is formed; with 0.017–0.1% B, M3B2 and M2B are formed, withover 0.1% B, M2B is formed.