Method for producing duplex stainless steel pipe
US8293037B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2011 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Jul 18, 2031 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for producing a duplex stainless steel pipe having a minimum yield strength of 758.3 to 965.2 MPa, comprises first hot working and optionally solution heat treating a duplex stainless steel material pipe having a chemical composition consisting, by mass %, of C: 0.03% or less, Si: 1% or less, Mn: 0.1 to 4%, Cr: 20 to 35%, Ni: 3 to 10%, Mo: 0 to 6%, W: 0 to 6%, Cu: 0 to 3% and N: 0.15 to 0.60%, the balance being Fe and impurities. The pipe is then cold rolled under conditions that the working ratio Rd, in terms of the reduction of area, in the final cold rolling step falls within a range from 10 to 80%, and formula (1) is satisfied:Rd=exp[{In(MYS)−In(14.5×Cr+48.3×Mo+20.7×W+6.9×N)}/0.195] (1)wherein Rd is a reduction in area %, MYS is the targeted yield strength (MPa), and Cr, Mo, W and N are in mass %.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.