AUSTENITIC STAINLESS STEEL TUBE HAVING EXCELLENT STEAM OXIDATION RESISTANCE, AND METHOD FOR PRODUCING SAME

• Main Authors: NISHIYAMA, YOSHITAKA, SETO, MASAHIRO, YOSHIZAWA, MITSURU, TANAKA, KATSUKI
• Format: Patent
• Language: English; French; German
• Published: 31.07.2013
• Subjects: ALLOYS; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; BLASTING; CHEMISTRY; DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OFGENERAL APPLICATION; ENGINEERING ELEMENTS AND UNITS; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEAT EXCHANGE IN GENERAL; HEATING; JOINTS OR FITTINGS FOR PIPES; LIGHTING; MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES,RIVETS, BOLTS OR WHEELS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; METHODS OF STEAM GENERATION; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PIPES; PUNCHING METAL; STEAM BOILERS; STEAM GENERATION; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; THERMAL INSULATION IN GENERAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS

There is provided an austenitic stainless steel pipe excellent in steam oxidation resistance. The austenitic stainless steel pipe excellent in steam oxidation resistance contains, by mass percent, 14 to 28% of Cr and 6 to 30% of Ni, and is configured so that a region satisfying the following Formula exists in a metal structure at a depth of 5 to 20 µm from the inner surface of the steel pipe: ± / ² × ´ / µ × 100 ‰¥ 0.3 where the meanings of symbols in the above Formula are as follows: ±: sum total of the number of pixels of digital image in region in which orientation difference of adjacent crystals detected by electron backscattering pattern is 5 to 50 degrees ²: the number of total pixels of digital image in region of measurement using electron backscattering pattern µ: analysis pitch width of electron backscattering pattern (µm) ´: grain boundary width (µm).