Method of manufacturing high chromium martensite steel pipe having excellent pitting resistance
US6136109A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1998 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | Oct 28, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high-Cr martensite steel pipe having excellent pitting resistance and method for manufacturing the same, which involves forming a pipe of steel including C: about 0.03 wt % or less, Si: about 0.5 wt % or less, Mn: about 0.5-3.0 wt %, Cr: about 10.0-14.0 wt %, Ni: about 0.2-2.0 wt %, Cu: about 0.2-1.0 wt % and N: about 0.03 wt % or less with the balance being Fe and incidental impurities, and having a value X shown as defined in the following formula (1) of about 12.2 or more. The pipe is quenched after austenitizing it at a temperature substantially equal to an A.sub.C3 point or higher, and the pipe is annealed in a temperature range from about 550.degree. C. or higher to a temperature lower than an A.sub.C1 point. EQU value X=(Cr%)+3(Cu%)-3(C%) (1) The high-Cr martensite steel pipe made by this method exhibits excellent pitting resistance and overall surface corrosion resistance even in an environment containing a carbonic acid gas, and further exhibits excellent weldability and toughness in the welding-heat-affected zones.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.