Kawasaki Steel Corporation

Jfe Steel Corporation

Hajime Takada

Yukinori Iizuka

Ikuo Yarita

Takashi Morii

Susumu Okada

Hideo Kuguminato

Yutaka Matsui

Takafumi Ozeki

Ryouichi Sugimoto

Akira Torao

Makoto Aratani

Masuto Shimizu

Kazuya Asano

Jun Kubota

Masato Iri

Fumihiko Ichikawa

Hidenori Miyake

Yasuo Tomura

Toshihiro Sasaki

The apparatus and method prevent inspection omission when ultrasonic flaw detection using a transducer array is applied to inspection of a test object being conveyed at a high speed. The method for inspecting a cross section of a test object using a transducer array comprised of many ultrasonic transducers arranged in one dimension includes the steps of transmitting ultrasonic waves from some or all of the ultrasonic transducers in the transducer array, receiving reflected waves generated by the transmitted ultrasonic waves using some or all of the ultrasonic transducers in the transducer array, converting the received signals into digital waveform signals, transforming the timing between the digitalized signal data received by each transducer element in at least one transducer group, which includes plural transducer elements selected from the transducer array, on the basis of the distances between the transducer element and spatially continuous focuses of receiving beam set to be formed in the test object; and summing all the timing-transformed signals received by transducer elements in the transducer group.

Method and apparatus for ultrasonic cross-sectional inspection

Even in measurement in which the measurement time is limited to a short time, soundness of a spot weld zone can be evaluated with high reliability without being influenced by a positional deviation between an ultrasonic probe and the spot weld zone and the coupling condition between an ultrasonic probe and a metal sheet. Specifically, ultrasonic waves propagating along the surface of a test object are transmitted in a plurality of directions from a plurality of wave sending positions outside the spot weld zone in metal sheets (), and ultrasonic waves propagating along the surface of the test object with propagation paths not including the spot weld zone and ultrasonic waves propagating along the surface of the test object with propagation paths including the spot weld zone are received at a plurality of wave receiving positions outside the spot weld zone to evaluate the soundness of the spot weld zone.

Ultrasonic method and apparatus for evaluating spot weld zone

The testing results, etc. of surface flaws such as cracks formed in or just below a surface of a body to be detected are displayed using colors within different color regions in the color space when displaying, on the basis of a preset threshold value, the test signal ranging in magnitude from zero to the threshold value and the test signal falling in magnitude beyond the threshold value while changing the color and/or the depth of color little by little within each of the color regions according to the magnitude of the test signal. This enables small flaw signals, etc. to be displayed without exception, thereby preventing small flaws, etc. from being overlooked.

Method of displaying signal obtained by measuring probe and device therefor

A method and apparatus for ultrasonic flaw detection of line focus type suitable for detection of flaws in nonmetallic materials included in an object. Ultrasonic transmitter and receiver elements of line focus type are opposed at a distance (L) with an object under test placed between them, and a maximum ultrasonic echo is obtained at a distance L expressed by: L &equals;0.75(FT&plus;FR)&minus;&lcub;(CS/CW)&minus;1&rcub;t where FT (mm) is the focal length in the medium of the ultrasonic transmitter element of line focus type, FR (mm) is the focal length in the medium of the ultrasonic receiver element line focus type, CS (m/sec) is the speed of ultrasound in an object under test, CW (m/sec) is the speed of ultrasound in the medium, and t (mm) is the thickness of the object under test.

Ultrasonic flaw detection method and instrument therefor

An ultrasonic testing method uses surface waves to prevent false detection of primary cracks, to lower the level of structural noises from grain boundaries, and to improve the detectability in the ultrasonic testing by surface wave testing of hot rolling rolls. A surface wave probe capable of transmitting and receiving a surface wave is provided with a piezoelectric element A, a resin wedge C disposed on the front surface of the piezoelectric element A and a damping block B disposed on the back surface. The surface wave probe is driven to produce a short pulse having a pulse length being at most 2.5 times the wavelength of the surface wave to be produced. A coupling liquid medium is supplied to the probe in accordance with the peripheral speed of the roll to be tested. Depending on the height of the reflected waves measured, the grinding allowance of the roll is determined, and the roll is ground according to the thus-determined grinding allowance. The roll may be tested while being partly ground, and the optimum grinding allowance of the roll may be determined.

Method and apparatus for ultrasonic testing of the surface of columnar structures, and method for grinding rolls by use of them

A flaw detecting method and apparatus for continuously testing a strip that is continuously carried through a liquid includes features for reducing air bubble generation in a liquid. The apparatus includes a liquid, carrying rolls for passage of the strip through the liquid, and ultrasonic testing probes arranged in the liquid for testing the strip. A carrying roll in contact with the liquid is fully immersed. Air bubble generation is inhibited to improve the testing reliability by at least one of (a) shielding the liquid dropping from the portion of the strip leaving the liquid, (b) reducing the dropping force of the liquid onto the liquid surface by inclining the strip, (c) installing the fully immersed carrying roll at a depth of at least 5 mm in the liquid, and (d) using a carrying speed of less than about 200 m/min. Upon manufacturing steel strips, testing is carried out in the stage of hot-rolled steel sheet, or, preferably, in pickling equipment.

Method and apparatus for detecting flaws in strip, method of manufacturing cold-rolled steel sheet and pickling equipment for hot-rolled steel strip

In measuring a distribution of crystal grains in metal sheet, an exciting frequency of ultrasonic wave is determined such that a wavelength of the ultrasonic wave propagated in a direction of the sheet thickness of the grains each having an aimed orientation is set at a value of twice the thickness of the sheet multiplied by about integers or about half integers, burst-like ultrasonic pulses having this frequency and including two or more waves are directed into the direction of the sheet thickness by use of an ultrasonic probe moving relatively with a body to be measured, multiple reflected waves generated from the bottom and top faces of the metal sheet upon the reflection from the sheet surface are caused to interfere with each other, the multiple reflected waves, which have interfered with each other, are detected, orientation of the grains in the metal sheet are estimated from the magnitudes in amplitude of the interferent multiple reflected waves thus detected, and the distribution of the grains in orientation in various portions, into which the ultrasonic wave is directed, is detected two-dimensionally.

Method of measuring distribution of crystal grains in metal sheet and

Growing community of inventors

Chiba, Japan

Hajime Takada