Austenitic-ferritic duplex stainless steel sheet

An austenitic-ferritic duplex stainless steel sheet, comprising a chemical composition containing, in mass %,

• C:
• 0.100% or less,
• Si:
• 1.00% or less,
• Mn:
• 2.2% to 7.0%,
• P:
• 0.07% or less,
• S:
• 0.030% or less,
• Cr:
• 18.0% to 24.0%,
• Ni:
• 0.1% to 3.0%,
• Mo:
• 0.01% to 1.00%,
• Cu:
• 0.1% to 3.0%,
• Ag:
• 0.010% to 0.120%, and
• N:
• 0.15% to 0.30%, and
• at least one selected from the group consisting of
• B:
• 0.0010% to 0.0100%, and
• REM:
• 0.010% to 0.100%,
• with the balance consisting of Fe and inevitable impurities, wherein
• the austenitic-ferritic duplex stainless steel sheet satisfies the following formula (1),
• (30×[% B]+1.2×[% REM])/[% Ag]≥1.00 (1)
• where [% Ag], [% B] and [% REM] are the contents in mass % of Ag, B and REM in the chemical composition, respectively.