Method of production of high-nitrogen ferritic heat-resisting steel
US5204056A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 31, 1992 |
| Grant date | Apr 20, 1993 |
| Priority date | — |
| Expiry date | Jul 31, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/001
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high-nitrogen ferritic heat-resisting steel comprises, in weight percent, 0.01-0.30% C, 0.02-0.80% Si, 0.20-1.00% Mn, 8.00-13.00% Cr, 0.50-3.00% W, 0.005-1.00% Mo, 0.05-0.50% V, 0.02-0.12% Nb and 0.10-0.50% N and is controlled to include not more than 0.050% P, not more than 0.010% S and not more than 0.020% O, the balance being Fe and unavoidable impurities. The steel may optionally comprise (A) one or both of 0.01-1.00% Ta and 0.01-1.00% Hf and/or (B) one or both of 0.0005-0.10% Zr and 0.01-0.10% Ti. A method of producing the steel comprises melting and equilibrating the steel components in an atmosphere of a mixed gas of a prescribed nitrogen partial pressure or nitrogen gas and thereafter casting or solidifying the melt in an atmosphere controlled to have a nitrogen partial pressure of not less than 1.0 ata and a total pressure of not less than 4.0 ata, with the relationship between the partial pressure p and the total pressure P.sub.t being EQU 10.sup.P <P.sub.t.sup.0.37 +log.sub.10 6.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.