Duplex stainless steel

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and one or two elements selected from group 1 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 1 elements
• Cu:
• 0.01-2.0%
• W:
• 0.01-1.5%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element selected from group 2 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 2 elements
• V:
• 0.01-0.50%
• Ti:
• 0.01-0.50%
• Nb:
• 0.01-0.50%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element selected from group 3 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 3 elements
• Ca:
• 0.0005-0.010%
• Mg:
• 0.0005-0.010%
• B:
• 0.0005-0.010%
• Zr:
• 0.01-0.50%
• Y:
• 0.001-0.20%
• Rare earth elements:
• 0.0005-0.010%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%. Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element each selected from group 1 and 2 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 1 elements
• Cu:
• 0.01-2.0%
• W:
• 0.01-1.5%
• Group 2 elements
• V:
• 0.01-0.50%
• Ti:
• 0.01-0.50%
• Nb:
• 0.01-0.50%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element each selected from group 1 and 3 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 1 elements
• Cu:
• 0.01-2.0%
• W:
• 0.01-1.5%
• Group 3 elements
• Ca:
• 0.0005-0.010%
• Mg:
• 0.0005-0.010%
• B:
• 0.0005-0.010%
• Zr:
• 0.01-0.50%
• Y:
• 0.001-0.20%
• Rare earth elements:
• 0.0005-0.010%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element each selected from group 2 and 3 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 2 elements
• V:
• 0.01-0.50%
• Ti:
• 0.01-0.50%
• Nb:
• 0.01-0.50%
• Group 3 elements
• Ca:
• 0.0005-0.010%
• Mg:
• 0.0005-0.010%
• B:
• 0.0005-0.010%
• Zr:
• 0.01-0.50%
• Y:
• 0.001-0.20%
• Rare earth elements:
• 0.0005-0.010%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.

A duplex stainless steel containing, by weight,

• Si:
• 2.0% or less, Mn:2.0% or less,
• Cr:
• 22.0-24.0%, Ni:
• 4.5-6.5%,
• Mo:
• 4.0-4.8%, Al:
• 0.001-0.15%,
• N:
• 0.25-0.35%,
• and at least one element each selected from group 1, 2 and 3 elements listed below, the remainder of Fe and inevitable impurities including 0.03% or less C, 0.05% or less P and 0.005% or less S, which has an RVS value defined by equation 1 below, 7 or less, and a PREW value defined by equation 2 below, greater than 40:
• Group 1 elements
• Cu:
• 0.01-2.0% Cu
• W:
• 0.01-1.5% W
• Group 2 elements
• V:
• 0.01-0.50%
• Ti:
• 0.01-0.50%
• Nb:
• 0.01-0.50%
• Group 3 elements
• Ca:
• 0.0005-0.010%
• Mg:
• 0.0005-0.010%
• B:
• 0.0005-0.010%
• Zr:
• 0.01-0.50%
• Y:
• 0.001-0.20%
• Rare earth elements:
• 0.0005-0.010%
• RVS=›1.100.times.(%Cr/52.0)+9.888.times.(%Mo/95.94)+2.045.times.(%W/183.85) !/1.738.times.(%Ni/58.71) 1
• PREW=%Cr+3.3.times.(%Mo+0.5.times.%W)+16.times.%N 2.