Abstract: An ultrasonic flaw detection device includes: a matrix array probe; an ultrasonic wave transmitting and receiving unit that controls the matrix array probe; and an evaluation unit that detects a planar defect based on the reflected ultrasonic waves received by the ultrasonic wave transmitting and receiving unit. The matrix array probe has a plurality of vibration elements arranged lattice-like, an array pitch of the vibration elements in the pipe axis direction is larger than a wavelength of ultrasonic waves transmitted and received, widths of the vibration elements in the pipe axis direction decrease outward in the pipe axis direction from a pipe axis direction center position of the matrix array probe, and the widths and center coordinates of the vibration elements in the pipe axis direction have been adjusted such that all of ultrasonic waves from the vibration elements overlap in a focal position control range for the ultrasonic waves.

Abstract: A detecting method of optically detecting a surface defect of a moving steel material includes an irradiation step of irradiating an examination target part with illumination light beams from different directions by two or more distinguishable light sources whose light emission durations are set based on at least an allowable positional displacement of an image, the two or more distinguishable light sources repeatedly emitting light such that their light emission timings thereof do not overlap each other; and a detection step of obtaining images by reflected light beams of the respective illumination light beams and detecting a surface defect in the examination target part by executing subtraction processing between the obtained images.

Abstract: An ultrasonic flaw detection device includes: a matrix array probe; an ultrasonic wave transmitting and receiving unit that controls the matrix array probe; and an evaluation unit that detects a planar defect based on the reflected ultrasonic waves received by the ultrasonic wave transmitting and receiving unit. The matrix array probe has a plurality of vibration elements arranged lattice-like, an array pitch of the vibration elements in the pipe axis direction is larger than a wavelength of ultrasonic waves transmitted and received, widths of the vibration elements in the pipe axis direction decrease outward in the pipe axis direction from a pipe axis direction center position of the matrix array probe, and the widths and center coordinates of the vibration elements in the pipe axis direction have been adjusted such that all of ultrasonic waves from the vibration elements overlap in a focal position control range for the ultrasonic waves.

Abstract: A surface inspection method for a steel pipe detects a surface defect on a hot steel pipe, and includes: an imaging step of imaging a self-luminous image of the hot steel pipe; a correcting step of making more uniform luminance variation in a circumferential direction of the self-luminous image and correcting the self-luminous image; and a detecting step of detecting a surface defect based on the self-luminous image corrected at the correcting step.

Abstract: A surface defect detecting method of optically detecting a surface defect of a steel material includes: an irradiation step of irradiating an examination target part with illumination light beams from different directions by using two or more distinguishable light sources; and a detection step of obtaining images by reflected light beams of the respective illumination light beams and detecting a surface defect in the examination target part by executing subtraction processing between the obtained images.

Abstract: A detecting method of optically detecting a surface defect of a moving steel material includes an irradiation step of irradiating an examination target part with illumination light beams from different directions by two or more distinguishable light sources whose light emission durations are set based on at least an allowable positional displacement of an image, the two or more distinguishable light sources repeatedly emitting light such that their light emission timings thereof do not overlap each other; and a detection step of obtaining images by reflected light beams of the respective illumination light beams and detecting a surface defect in the examination target part by executing subtraction processing between the obtained images.

Abstract: An ultrasonic measurement method includes: a measuring point setting step of setting an arbitrary measuring point near a weld portion inside of steel material and assuming a virtual reflecting surface that includes the measuring point and is parallel to a weld line direction; a focused beam setting step of transmitting ultrasonic waves of a shear wave mode and focusing onto the measuring point via a coupling medium at a predetermined incident angle with respect to the virtual reflecting surface; a detecting step of detecting reflected waves of the transmitted ultrasonic waves at a boundary between a base metal portion and the weld portion; and an evaluating step of evaluating a shape of the weld portion based on the reflected waves.

Abstract: A surface defect detecting method of optically detecting a surface defect of a steel material includes: an irradiation step of irradiating an examination target part with illumination light beams from different directions by using two or more distinguishable light sources; and a detection step of obtaining images by reflected light beams of the respective illumination light beams and detecting a surface defect in the examination target part by executing subtraction processing between the obtained images.

Abstract: A surface inspection method for a steel pipe detects a surface defect on a hot steel pipe, and includes: an imaging step of imaging a self-luminous image of the hot steel pipe; a correcting step of making more uniform luminance variation in a circumferential direction of the self-luminous image and correcting the self-luminous image; and a detecting step of detecting a surface defect based on the self-luminous image corrected at the correcting step.

Abstract: An ultrasonic flaw detection method to detect flaws on an inner surface of a metallic pipe using ultrasonic waves includes a waveform hold step that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward the inner surface and the metallic pipe are moved relative to each other, a signal analyzing step that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held, and a flaw detecting step that detects flaws on the inner surface based on the path length and the change rate of the path length.

Abstract: A method for manufacturing an electric resistance steel pipe having a good toughness at a welded portion is provided, the method being capable of stably manufacturing an electric resistance welded steel pipe having a desirable toughness at a welded portion although a steel strip serving as a base material has a dimensional variation. Groove shapes and are applied to edges and of an open pipe, an edge shape monitor continuously captures images of the edges and immediately before electric resistance welding, and the captured images are input to an arithmetic processing unit for image processing.

Abstract: An ultrasonic measurement method includes: a measuring point setting step of setting an arbitrary measuring point near a weld portion inside of steel material and assuming a virtual reflecting surface that includes the measuring point and is parallel to a weld line direction; a focused beam setting step of transmitting ultrasonic waves of a shear wave mode and focusing onto the measuring point via a coupling medium at a predetermined incident angle with respect to the virtual reflecting surface; a detecting step of detecting reflected waves of the transmitted ultrasonic waves at a boundary between a base metal portion and the weld portion; and an evaluating step of evaluating a shape of the weld portion based on the reflected waves.

Abstract: An ultrasonic flaw detection method to detect flaws on an inner surface of a metallic pipe using ultrasonic waves includes a waveform hold step that acquires and holds waveform data of an echo signal when an ultrasonic probe that generates ultrasonic signals toward the inner surface and the metallic pipe are moved relative to each other, a signal analyzing step that calculates a path length up to receiving an echo signal from the inner surface and a change rate of the path length based on the waveform data held, and a flaw detecting step that detects flaws on the inner surface based on the path length and the change rate of the path length.

Abstract: According to the present invention, penetrators can be adequately determined as flaws. In particular, a welded zone of a pipe is subjected to ultrasonic flaw detection at least in a pipe axial direction, and the quality of the pipe is evaluated using observed values in units of a predetermined area in a pipe thickness direction and the pipe axial direction. The length of one side of the predetermined area is an ultrasound beam width or more and a pipe thickness or less. The quality of the pipe can be evaluated while shifting the predetermined area in the pipe axial direction by using an average value of the observed values within the predetermined area. The length of one side of the predetermined area can be made an ultrasound beam width or more and a pipe thickness or less.

Abstract: A base material portion of an electric resistance welded steel pipe has a composition including C at 0.25 to 0.55%, Si at 0.01 to 1.0%, Mn at 0.2 to 3.0%, Al at not more than 0.1% and N at 0.0010 to 0.0100%, with the balance being represented by Fe and inevitable impurities, and the weld defect area, which is a projected area of a weld defect in an electric resistance weld zone, is less than 40000 ?m2.

Abstract: The present invention has a structure capable of detecting the scattered-type penetrator having oxides each with the size of several ?m 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: In an electric resistance welded steel pipe with excellent weld toughness for a line pipe, the area fraction of minute defects each having a maximum length of less than 50 ?m in a projection plane of an electric resistance welded seam is in the range of 0.000006 to 0.026, and the absorbed energy at ?40° C. measured by a method for an impact test of metallic materials is 315 J or more.

Abstract: An ultrasonic flaw detection is performed to a welded portion 2 of a pipe body 1, a defect detection threshold value is determined based on the signal intensity difference between the total area of the defects existing in the region of an ultrasonic beam on a welded surface and an artificial defect, and a quality control of the pipe body is performed based on the defect detection threshold value. An equivalent defect diameter is determined from the defect density on the welded surface of the welded portion of the pipe body in a pipe axis direction and the area of the ultrasonic beam on the welded surface based on the total area of the defects existing in the region of the ultrasonic beam, and the defect detection threshold value is determined based on the equivalent defect diameter and the signal intensity difference of the artificial defect.

Abstract: A method for detecting a crater end of a continuously cast product, including installing an ultrasonic shear wave sensor for transmitting an ultrasonic shear wave to the continuously cast product and receiving the transmitted ultrasonic shear wave in a continuous casting machine, detecting based on variations of an ultrasonic signal received by the ultrasonic shear wave sensor that the crater end of the cast product is matched with the installed position of the ultrasonic shear wave sensor, calibrating a physical property value used in a calculation based on a heat condition equation such that the crater end computed based on the heat condition equation using casting conditions at that time is matched with the installed position of the ultrasonic shear wave sensor, and after the calibration, determining the crater end by the calculation based on the heat condition equation under respective casting conditions by using the calibrated physical property value.

Abstract: Disclosed are an ultrasonic testing system and an ultrasonic testing technique for a pipe member capable of detecting minute flaws of several hundreds of microns or less located at positions in the wall thickness inside portion of a welded portion of a seam-welded pipe and the like without omission and further easily setting optimum conditions when the size of the pipe is changed. A transmitting beam, which is focused to the welded portion at an oblique angle, is transmitted using a part of the group of transducer elements of a linear array probe as a group of transducer elements for transmission, a receiving beam, which is focused at the focusing position of the transmitting beam at an oblique angle, is formed using the transducer elements of a portion different from the above group of transducer elements for transmission as a group of transducer elements for reception, and a flaw echo is received from the welded portion.