Cast steel material for pressure vessels and method of making a pressure vessel by using same
US6254697A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2000 |
| Grant date | Jul 3, 2001 |
| Priority date | — |
| Expiry date | Mar 16, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/54
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a cast steel material for pressure vessels which has improved impact resistance (weldability) and toughness while maintaining its creep rupture strength at a level equal to or higher than the excellent creep rupture strength currently possessed by CrMoV cast steel, as well as a method of making a pressure vessel (or cast steel article) by using this cast steel material which permits a pressure vessel to be made without requiring a material working step such as forging. Specifically, the present invention relates to a cast steel material for pressure vessels which contains C, Si, Mn, Ni, Cr, Mo, V, W, Nb and/or Ta, B, Ti, Al, N, O, P and S in predetermined proportions, the balance being Fe and incidental impurities, provided that the contents of Ti, Al, O and N satisfies the following relationship: EQU N-0.29{Ti-1.5((O-0.89Al)}.ltoreq.0.0060%, and to a method of making a pressure vessel wherein the aforesaid cast steel material is cast and then heat-treated under predetermined conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.