High strength electric resistance welded steel pipe and method for producing high strength electric resistance welded steel pipe

• Main Authors: Ishitsuka, Tetsuo, Tsusue, Takashi, Kobayashi, Shunichi, Kawano, Hideto, Yoshida, Osamu, Iwamoto, Shuji
• Format: Patent
• Language: English
• Published: 05.05.2020
• Subjects: ALLOYS; BLASTING; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; 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; HEATING; JOINTS OR FITTINGS FOR PIPES; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; LIGHTING; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PIPES; PUNCHING METAL; ROLLING OF METAL; SOLDERING OR UNSOLDERING; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; THERMAL INSULATION IN GENERAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS; WELDING; WORKING BY LASER BEAM

Electric resistance welded steel pipe securing the high strength and high toughness demanded from oil well pipe in recent years. The metal structure in a region having a width of 0.5 mm in both the thickness directions from a reference point, when using a point defined as a point ¼ of the thickness in the thickness direction from the surface in the base material part of the steel as the reference point, consists of polygonal ferrite: 10 area % or less and a balance: bainitic ferrite. The thickness is 15 mm or more.