FERRITIC STAINLESS STEEL AND STEEL SHEET FOR HEAT PIPES, AND HEAT PIPE AND HIGH-TEMPERATURE EXHAUST HEAT RECOVERY SYSTEM

• Main Authors: NISHIDA YUKIHIRO, FUJIMURA YOSHITOMO, KAFUKU KAZUAKI, OKU MANABU, KOHARA KIMIO, MUKOBARA YUKI
• Format: Patent
• Language: English
• Published: 20.05.2010
• Subjects: ALLOYS; BLASTING; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; HEAT EXCHANGE IN GENERAL; HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS,IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT; HEATING; LIGHTING; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL ENGINEERING; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS

Provided is a ferritic stainless steel for heat pipes of high-temperature exhaust heat recovery systems, which comprises, in terms of % by mass, from 16 to 32% of Cr, at most 0.03% of C, at most 0.03% of N, at most 3% of Si, at most 2% of Mn, at most 0.008% of S, from 0 to 0.3% of Al, and at least one of at most 0.7% of Nb, at most 0.3% of Ti, at most 0.5% of Zr and at most 1% of V, and optionally at least one of at most 3% of Mo, at most 3% of W, at most 3% of Cu, at most 0.1% of Y, at most 0.1% of REM (rare earth metal) and at most 0.01% of Ca, with a balance of Fe and inevitable impurities, and which satisfies at least the following formula (1), formula (2) and formula (5): Cr+3(Mo+Cu) 20  (1) Cr+3(Si+Mn+Al−Ti) 20  (2) 0.037{(C+N)/(V+Ti+0.5Nb+0.5Zr)}+0.001 0.01  (5).