Abstract:
The present invention has a structure capable of detecting the scattered-type penetrator having oxides each with the size of several µm sparsely and widely dispersed. Specifically, the structure includes a wave transmission unit 6 for transmitting an ultrasonic wave to the welded surface of the welded portion 2 in a pipe axial direction of the pipe 1 such that the beam width of a transmission beam 8 is brought into a range from 0.5 mm to 2.5 mm, and a wave reception unit 7 for receiving at least a portion of the reflection wave (reception beam 9) at the welded surface. The wave transmission unit 6 and the wave reception unit 7 include transmission/reception units formed of different groups of transducer elements on at least one or more array probes 5 arranged in the circumferential direction of the pipe.
Abstract:
【課題】良好なねじ部(鋼管外面のねじ形状が規定のJIS形状であり、かつ鋼管内面の凹凸量が小さい)を備えた内面樹脂ライニング薄肉鋼管およびその製造方法を提供する。【解決手段】JIS G 3452の配管用炭素鋼管に対して、外径が同じで、厚さが100%未満78%以上であり、鋼管内面に樹脂ライニングを有し、鋼管端部に、鋼管外面にJIS B 0202またはJIS B 0203に基づくねじを有するねじ部を備え、前記ねじ部における鋼管内面の凹凸量が最大高さRzで200.0μm以下であることを特徴とする内面樹脂ライニング薄肉鋼管。【選択図】図1
Abstract:
PROBLEM TO BE SOLVED: To overcome the difficulty of efficiently heating an electric resistance welded steel pipe across its entire wall thickness to a target temperature in a conventional heat-treatment (seam annealing) method of a welded part of the pipe. SOLUTION: A plurality of stands 15, each of which having induction coils 11a and 13a disposed at both inside and outside of the pipe 5, is disposed in a direction in which the pipe is passed, and the welded part is subjected to induction heating from both inside and outside of the pipe. At a stand between a first stand and a stand other than the last stand, the welded part is heated until the inside and outside temperatures of the welded part at the outlet side of the stand exceed an Ac 3 transformation temperature, and at the following stands, the welded part is heated so that the inside and outside temperatures of the welded part are kept at a prescribed temperature higher than the Curie point and that the center of thickness of the welded part reaches a target temperature. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method for manufacturing an electric resistance welded tube that is excellent in buckling resistance and hard to be affected by buckling due to an earthquake or a frozen soil. SOLUTION: The uppermost point 12 of the groove bottom of the lower roll of each fin pass stand is positioned higher than an extension line 15A formed by extending, to the downstream side, a downhill 15 of the bottom position of a material that is just before a first fin pass stand, and is separated more upward from the extension line 15A as the uppermost point 12 goes further to rear stages. Further, a downhill of the outer peripheral bottom position of the material in a squeeze is preferably positioned on or above an extension line 15B formed by extending, to the downstream side, a downhill of the bottom position of the material just after a final fin pass stand. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To solve a problem of not sufficiently improving buckling resistance property of an electric resistance welded tube by conventional technology. SOLUTION: In the manufacturing method of the electric resistance welded tube, a steel strip is roll formed while it is being passed, both abutted ends of the strip in a width direction are electric-resistance-welded to form a tube 10, heat treatment is applied to an electric resistance welded area, and then the tube is straightened. When straightening the tube, a rotary straightening machine 8 is used wherein distance between the stands of the rotary straightening machine is set to satisfy the range defined by a formula: L≠D×π×tanα×A, wherein L is the distance between the strands of the rotary straightening machine, D is the outer diameter of the tube, π is a circular ratio, α is the roll inclination angle of the rotary straightening machine, and A is a number within a range of (N/2)±0.025. COPYRIGHT: (C)2010,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method for manufacturing an electric resistance welded tube excellent in characteristics of a weld zone, in which excellent weld quality is maintained, by properly giving a tapered shape to the width direction end part of a strip material before electric resistance welding when manufacturing the electric resistance welded tube by abutting right and left end parts in the width direction of the strip material on each other and subjecting them to electric resistance welding. SOLUTION: After giving a tapered shape to the upper and/or lower face side of either of right and left end parts in the width direction of a strip material 20, electric resistance welding is conducted. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a pipe end joint position detection apparatus for correcting an error in a detection position due to the occurrence of a step generated in a joint position. SOLUTION: The pipe end joint position detection apparatus of a resin-coated pipe 3 comprises: an eddy current detector 1 for detecting the pipe end joint position 4 by using an eddy current after a resin is coated; a step quantity measurement instrument 2 for measuring the step quantity 5 generated at a pipe end before and after the pipe end joint position 4; and a correction calculator 8 for correcting a detection position signal of the pipe end joint position 4 only if a measurement result of the step quantity 5 is a fixed quantity or more. COPYRIGHT: (C)2011,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method for manufacturing a laser-welded steel pipe stably in a high yield by highly and precisely determining a laser welding situation and by changing a welding condition on the basis of the determined result. SOLUTION: The irradiating region of a laser beam irradiated from an outer face side at an edge portion is monitored from the inner face side of an open pipe. When a key hole penetrating to the inner face side of the open pipe is observed, the welding condition of the laser beam is continuously kept. When the keyhole penetrating to the inner face side of the open pipe is not observed, the welding condition of the laser beam is changed. Thus, the welding operation is performed while the keyhole penetrating through the open pipe from the outer face side to the inner face side is formed in the irradiating region of the laser beam. COPYRIGHT: (C)2010,JPO&INPIT