Title of Invention

DUPLEX STEEL ALLOY

Abstract The present invention relates to a stainless steel alloy, closer determined a duplex stainless steel alloy with ferritic-austenitic matrix and with high resistance to corrosion in combination with good structural stability and hotworkability, in paricular a duplex stainless steel with a content of ferrite of 40-65% and a well balanced compositon that imparts material corrosion properties, which makes it is more suitable for use in chloride-containing environments than earlier been considered being possible. The total PRE- or PREW-number exceeds 44 a PRE-number on at least between 46 and 50 in both the austenite phase and the ferrite phase, whereby PRE = %Cr + 3,3%Mo + 16N and PREW = %Cr + 3,3(%Mo + 0,5%W) + 16N, wherein % considers weight-% and ratio between PRE(W)-value for the austenite phase and PRE(W)-value for the ferrite phase lies between 0,90 and 1,15. These purposes are fulfilled according to the present invention with duplex stainless steel alloys which contain (in weight-%) up to 0,03% C, up to 0,5% Si, 24,0-30,0% Cr, 4,9-10,0% Ni, 3,0-5,0% Mo, 0,28-0,5% N, 0-3,0% Mn, 0-0,0030% B, up to 0,010%, 0-0,03% Al, 0-0,010% Ca, 0-3,0% W, 0-2,0% Cu, 0-3,5% Co, 0-0,3% Ru, balance Fe and inevitable impurities.
Full Text

Documents:


Patent Number 200910
Indian Patent Application Number 00420/KOL-NP/2004
PG Journal Number N/A
Publication Date 19-Jan-2007
Grant Date 19-Jan-2007
Date of Filing 31-Mar-2004
Name of Patentee SANDVIK INTELLECTUAL PROPERTY AB
Applicant Address OF S-811 81 SANDVIKEN ,SWEDEB A SWEDISH COMPANY
Inventors:
# Inventor's Name Inventor's Address
1 SUNDSTROM ANN BARRSATRAGATAN 71,S-811 36 SANDVIKEN SWEDEN A SWEDISH COMPANY
2 NYSTROM, ANNA-LENA PERSBOGATAN 5, S-811 32 SANDVIKEN,SWEDEN
3 KANGAS, PASI KASRLAVAGEN 37, S-811 36 SANDVIKEN,SWEDEN
PCT International Classification Number C22C 38/44,38/46,
PCT International Application Number PCT/SE02/01564
PCT International Filing date 2002-09-02
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 0102931-3 2001-09-02 Sweden