Abstract: Disclosed is a duplex stainless clad steel plate in which a duplex stainless steel plate as a cladding metal is bonded or joined to one or both surfaces of a base steel plate, in which the base steel plate comprises a predetermined chemical composition such that Nb/N is 3.0 or more and Ceq is 0.35 to 0.45, and the duplex stainless steel plate comprises: a predetermined chemical composition such that PI is 34.0 to 43.0; and a microstructure containing a ferrite phase in an area fraction of 35% to 65%, and in the microstructure, an amount of precipitated Cr is 2.00% or less and an amount of precipitated Mo is 0.50% or less.

Abstract: Disclosed is a duplex stainless clad steel plate in which a duplex stainless steel plate as a cladding metal is bonded or joined to one or both surfaces of a base steel plate, in which the base steel plate comprises a predetermined chemical composition such that Nb/N is 3.0 or more and Ceq is 0.35 to 0.45, and the duplex stainless steel plate comprises: a predetermined chemical composition such that PI is 33.0 to 38.0; and a microstructure containing a ferrite phase in an area fraction of 35% to 65%, and in the microstructure, an amount of precipitated Cr is 1.00% or less and an amount of precipitated Mo is 0.50% or less.

Abstract: Disclosed is a clad steel plate with further improved low temperature toughness along with excellent HIC resistance while ensuring a tensile strength of 535 MPa or more. A clad steel plate includes: a base steel; and a clad metal made of a corrosion resistant alloy bonded to one surface of the base steel, in which the base steel has: a chemical composition with appropriately controlled values of ACR and PHIC; and a steel microstructure in which bainite is present in an area fraction of 94% or more at a ½ thickness position in a thickness direction of the base steel, and with an average crystal grain size of 25 ?m or less, and shear strength at a bonded interface between the base steel and the cladding metal is 300 MPa or more.

Abstract: Disclosed is a clad steel plate with further improved low temperature toughness along with excellent HIC resistance while ensuring a tensile strength of 535 MPa or more. A clad steel plate includes: a base steel; and a clad metal made of a corrosion resistant alloy bonded to one surface of the base steel, in which the base steel has: a chemical composition with appropriately controlled values of ACR and PHIC; and a steel microstructure in which bainite is present in an area fraction of 94% or more at a ½ thickness position in a thickness direction of the base steel, and with an average crystal grain size of 25 ?m or less, and shear strength at a bonded interface between the base steel and the cladding metal is 300 MPa or more.

Abstract: Disclosed is a duplex stainless clad steel plate in which a duplex stainless steel plate as a cladding metal is bonded or joined to one or both surfaces of a base steel plate, in which the base steel plate comprises a predetermined chemical composition such that Nb/N is 3.0 or more and Ceq is 0.35 to 0.45, and the duplex stainless steel plate comprises: a predetermined chemical composition such that PI is 34.0 to 43.0; and a microstructure containing a ferrite phase in an area fraction of 35% to 65%, and in the microstructure, an amount of precipitated Cr is 2.00% or less and an amount of precipitated Mo is 0.50% or less.

Abstract: Disclosed is a duplex stainless clad steel plate in which a duplex stainless steel plate as a cladding metal is bonded or joined to one or both surfaces of a base steel plate, in which the base steel plate comprises a predetermined chemical composition such that Nb/N is 3.0 or more and Ceq is 0.35 to 0.45, and the duplex stainless steel plate comprises: a predetermined chemical composition such that PI is 33.0 to 38.0; and a microstructure containing a ferrite phase in an area fraction of 35% to 65%, and in the microstructure, an amount of precipitated Cr is 1.00% or less and an amount of precipitated Mo is 0.50% or less.

Abstract: A thick steel plate is provided by heating a continuously-cast slab, hot forging the continuously-cast slab using opposing dies having respective short sides differing such that when a short side length of a die having a shorter one of the short sides is taken to be 1, a short side length of a die having a longer one of the short sides is 1.1 to 3.0, allowing cooling to obtain a steel raw material, reheating the steel raw material, performing hot rolling of the steel raw material including at least two passes carried out, allowing cooling to obtain a thick steel plate, reheating the thick steel plate to at least the Ac3 temperature and no higher than 1050° C., rapidly cooling the thick steel plate to 350° C. or lower, and tempering the thick steel plate at at least 550° C. and no higher than 700° C.

Abstract: A cladding material for stainless steel clad steel plate, includes, by mass %, 0.03% or less carbon, 1.5% or less silicon, 2.0% or less manganese, 0.04% or less phosphorus, 0.03% or less sulfur, 22.0% to 25.0% nickel, 21.0% to 25.0% chromium, 2.0% to 5.0% molybdenum, 0.15% to 0.25% nitrogen, and the balance being iron and incidental impurities, wherein critical pitting temperature (CPT) after normalization as determined in accordance with ASTM G48-03 Method E is 45° C. or higher, and corrosion loss at a welded zone as determined by a corrosion test in accordance with NORSOK Standard M-601 is 1.0 g/m2 or less.

Abstract: A thick steel plate is provided by heating a continuously-cast slab, hot forging the continuously-cast slab using opposing dies having respective short sides differing such that when a short side length of a die having a shorter one of the short sides is taken to be 1, a short side length of a die having a longer one of the short sides is 1.1 to 3.0, allowing cooling to obtain a steel raw material, reheating the steel raw material, performing hot rolling of the steel raw material including at least two passes carried out, allowing cooling to obtain a thick steel plate, reheating the thick steel plate to at least the Ac3 temperature and no higher than 1050° C., rapidly cooling the thick steel plate to 350° C. or lower, and tempering the thick steel plate at at least 550° C. and no higher than 700° C.

Abstract: A stainless cladding steel plate with excellent sea water corrosion resistance includes a cladding metal including, in mass %, C: not more than 0.030%, Si: 0.02 to 1.50%, Mn: 0.02 to 2.0%, P: not more than 0.040%, S: not more than 0.030%, Ni: 22.0 to 25.0%, Cr: 22.0 to 26.0%, Mo: 3.5 to 5.0% and N: 0.10 to 0.25%, the balance being Fe and inevitable impurities, the cladding metal satisfying relation (1) and being such that amounts of chromium and molybdenum present as precipitates are not more than 0.3 mass % and not more than 0.2 mass %, respectively, Cr+3.3Mo+16N?40 ??(1) wherein chemical symbols indicate amounts in mass % of the respective elements.

Abstract: A base metal for a high-toughness clad plate has a shear area of 85% or more in a ?20° C. DWTT test and includes, in terms of % by mass, C: 0.030% to 0.10%, Si: 0.10% to 0.30%, Mn: 1.30% to 1.80%, P: 0.015% or less, S: 0.003% or less, Mo: 0.05% to 0.50%, V: less than 0.010%, Nb: 0.010% to 0.060%, Ti: 0.005% to 0.020%, Al: 0.040% or less, Ca: 0.0010% to 0.0040%, N: 0.0030% to 0.0060%, and the balance being Fe and unavoidable impurities.

Abstract: A stainless clad steel includes a stainless steel having Pitting Index of 35 or more as a cladding material, wherein the ratio of Cr concentration/Fe concentration in a passivation film portion of the above-described cladding material to Cr concentration/Fe concentration in a parent phase portion of the above-described cladding material is 1.20 or more and, in addition, the amount of precipitation of a ? (sigma) phase of the surface of the above-described cladding material is 2.0% or less on an area ratio basis.

Abstract: A cladding material for stainless steel clad steel plate, includes, by mass %, 0.03% or less carbon, 1.5% or less silicon, 2.0% or less manganese, 0.04% or less phosphorus, 0.03% or less sulfur, 22.0% to 25.0% nickel, 21.0% to 25.0% chromium, 2.0% to 5.0% molybdenum, 0.15% to 0.25% nitrogen, and the balance being iron and incidental impurities, wherein critical pitting temperature (CPT) after normalization as determined in accordance with ASTM G48-03 Method E is 45° C. or higher, and corrosion loss at a welded zone as determined by a corrosion test in accordance with NORSOK Standard M-601 is 1.0 g/m2 or less.

Abstract: A base metal for high-toughness clad plate having excellent toughness at a welded joint contains, in terms of mass %, C: 0.030 to 0.10%, Si: 0.10 to 0.30%, Mn: 1.00 to 1.60%, P: 0.015% or less, S: 0.003% or less, V: less than 0.010%, and at least one selected from Mo: 0.05 to 0.50%, Nb: 0.010 to 0.060%, Ti: 0.005 to 0.020%, Al: 0.040% or less, Ca: 0.0010 to 0.0040%, and N: 0.0030 to 0.0060%, the balance being Fe and unavoidable impurities, in which a percent ductile fracture is 85% or more in a ?20° C. DWTT test and vE?20° C. is 100 J or more at a HAZ 3 mm position.