FERRITIC STAINLESS STEEL AND METHOD FOR PRODUCING SAME, AND HEAT EXCHANGER EQUIPPED WITH FERRITIC STAINLESS STEEL AS MEMBER

• Main Authors: MATSUHASHI Tooru, TAMURA Yuuichi
• Format: Patent
• Language: English; French; German
• Published: 13.11.2019
• Subjects: ALLOYS; BLASTING; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OFGENERAL APPLICATION; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; HEAT EXCHANGE IN GENERAL; HEATING; LIGHTING; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL ENGINEERING; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS; WELDING; WORKING BY LASER BEAM

A ferritic stainless steel, which has excellent heat exchange properties, corrosion resistance and brazing property of the heat exchanger component, and a heat exchanger using the ferritic stainless steel are provided. The ferritic stainless steel includes, in a mass%, C: 0.030% or less, N: 0.020% or less, Si: 0.5% or less, Mn: 1.0% or less, P: 0.05% or less, S: 0.01% or less, Cr: 16% to 25%, Nb: 0.05% to 1.0%, Al: 0.003% to 0.20%, and a balance composed of Fe and unavoidable impurities. The Al oxide is present on the surface of the material, the surface coverage ratio by the Al oxide is 5% to 70%, the surface roughness in Ra measured by red laser is 0.010 µm to 0.15 µm, and the thickness from the surface to the point, which includes the value of a half peak of the Al content on the surface, satisfies 300 nm or less, the value of a half peak of the Al content being obtained from an elemental profile expressed by a cation ratio.