BENT STEEL PIPE AND METHOD FOR PRODUCING SAME

• Main Authors: OE, Taro, KAMITANI, Hiroki, SENDAI, Yusuke
• Format: Patent
• Language: English; French; German
• Published: 26.01.2022
• Subjects: ALLOYS; BLASTING; CHEMISTRY; 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; LIGHTING; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PIPES; PUNCHING METAL; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; THERMAL INSULATION IN GENERAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

A steel bend pipe (1) includes a straight pipe portion (2) and a bent portion (3) having a bending radius r not less than three times an outer diameter OD of the straight pipe portion (2), and has a chemical composition containing, in mass percent, C: 0.04 to 0.08%, Si: 0.05 to 0.50%, Mn: 1.00 to 1.70%, P: 0.015% or less, S: 0.002% or less, Cu: 0 to 0.50%, Ni: 0 to 0.50%, Cr: 0 to 0.50%, Mo: 0 to 0.50%, Sol.Al: 0 to 0.10%, Ca: 0 to 0.0050%, Nb: 0 to 0.050%, V: 0 to 0.10%, and Ti: 0 to 0.030%, with the balance being Fe and impurities, wherein Ceq (= C + Mn/6 + (Cr + Mo + V)/5 + (Cu + Ni)/15) is 0.35% or more, yield stresses of the straight pipe portion (2) and the bent portion (3) are 450 to 600 MPa, and Vickers hardnesses (HV10) of the straight pipe portion (2) and the bent portion (3) are 230 or less.