A method of analysing a component formed from a metal alloy to identify a possible defect, wherein the metal alloy comprises a first crystal grain region and the possible defect comprises a second crystal grain region aligned to a different axis to the first crystal grain region, the method comprising the steps of: obtaining a first image of the component illuminated using a first polarisation state of light, the first image comprising first polarisation data; obtaining a second image of the component illuminated using a second polarisation state of light different to the first polarisation state, the second image comprising second polarisation data; determining a difference in polarisation data for plural pixels of the first image between each pixel of the first image and a corresponding pixel of the second image; and identifying pixels corresponding to the second crystal grain region based on the difference in polarisation data.

A method of analysing a component formed from a metal alloy to identify a possible defect, wherein the metal alloy comprises a first crystal grain region and the possible defect comprises a second crystal grain region aligned to a different axis to the first crystal grain region, the method comprising the steps of: obtaining a first image of the component illuminated using a first polarisation state of light, the first image comprising first polarisation data; obtaining a second image of the component illuminated using a second polarisation state of light different to the first polarisation state, the second image comprising second polarisation data; determining a difference in polarisation data for plural pixels of the first image between each pixel of the first image and a corresponding pixel of the second image; and identifying pixels corresponding to the second crystal grain region based on the difference in polarisation data.

To provide a method for evaluating a corroded part, the method making it possible to specify only a waveform reflected by a corroded part and to evaluate the waveform. When a transmission unit (2) is moved on the surface of a metal pipe (60) and the distance between a corroded part (5) and the transmission unit (2) is changed, only a waveform portion A of ultrasonic waves reflected by the corroded part (5) moves toward the left or right along an X axis, and only the intensity of a noise waveform portion B included in a received wave changes upward or downward along a Y axis, which makes it possible to separate the waveform portion A and the noise waveform portion B of a longitudinal-wave surface wave reflected by the corroded part (5) and evaluate the waveform portion A in detail.

To provide a method for evaluating a corroded part, the method making it possible to specify only a waveform reflected by a corroded part and to evaluate the waveform. When a transmission unit (2) is moved on the surface of a metal pipe (60) and the distance between a corroded part (5) and the transmission unit (2) is changed, only a waveform portion A of ultrasonic waves reflected by the corroded part (5) moves toward the left or right along an X axis, and only the intensity of a noise waveform portion B included in a received wave changes upward or downward along a Y axis, which makes it possible to separate the waveform portion A and the noise waveform portion B of a longitudinal-wave surface wave reflected by the corroded part (5) and evaluate the waveform portion A in detail.

A corrosion monitoring device includes: a sensor unit that includes an insulating substrate, a stainless steel plate disposed on the insulating substrate and is configured of stainless steel, an aluminum piece joined to the stainless steel plate and configured of aluminum having a lower corrosion potential than the stainless steel and smaller electrical resistivity than the stainless steel, and extraction electrodes coupled to the stainless steel plate; and an ohm meter that measures an electrical resistance of the sensor unit when a current flows in the sensor unit.

A corrosion monitoring device includes: a sensor unit that includes an insulating substrate, a stainless steel plate disposed on the insulating substrate and is configured of stainless steel, an aluminum piece joined to the stainless steel plate and configured of aluminum having a lower corrosion potential than the stainless steel and smaller electrical resistivity than the stainless steel, and extraction electrodes coupled to the stainless steel plate; and an ohm meter that measures an electrical resistance of the sensor unit when a current flows in the sensor unit.

A method for measuring a residual stress, including irradiating a cast and forged steel product with X-rays; two-dimensionally detecting intensities of diffracted X-rays originating from the X-rays; and calculating a residual stress based on a diffraction ring formed by an intensity distribution of the diffracted X-rays, wherein the irradiating includes changing a condition for irradiation of the cast and forged steel product with the X-rays, the irradiating is a step of performing the changing each time the cast and forged steel product is irradiated with the X-rays, the calculating is a step of calculating the residual stress each time the cast and forged steel product is irradiated with the X-rays, and the method further includes averaging a plurality of residual stresses calculated in the calculating after the irradiating, the detecting, and the calculating are performed in this order a plurality of times.

A method of analysing a component formed from a metal alloy to identify a possible defect, wherein the metal alloy comprises a first crystal grain region and the possible defect comprises a second crystal grain region aligned to a different axis to the first crystal grain region, the method comprising the steps of: obtaining a first image of the component illuminated using a first polarisation state of light, the first image comprising first polarisation data; obtaining a second image of the component illuminated using a second polarisation state of light different to the first polarisation state, the second image comprising second polarisation data; determining a difference in polarisation data for plural pixels of the first image between each pixel of the first image and a corresponding pixel of the second image; and identifying pixels corresponding to the second crystal grain region based on the difference in polarisation data.

A fatigue level estimation method includes estimating a fatigue portion in a metal material, measuring a distribution of a misorientation in the fatigue portion, obtaining a specific area ratio of the fatigue portion based on the distribution of the misorientation in the fatigue portion, and obtaining an estimated fatigue level of the metal material based on at least one of the specific area ratio of the fatigue portion and a degree of change in the specific area ratio of the fatigue portion. The specific area ratio of the fatigue portion is a ratio of a specific area existing in a measurement area of the fatigue portion.

A plurality of captured images is acquired while changing a light illumination state. Each captured image is compared with a corresponding reference image to acquire a region where the captured image is darker than the reference image as a dark defect candidate region. From each of a plurality of captured images, a region where the captured image is lighter than the reference image is acquired as a lightness/darkness inverted region. Among the dark defect candidate regions, those that do not overlap by a prescribed criterion or more with any of the lightness/darkness inverted regions are excluded from defect candidates, and then the presence of a defect is acquired on the basis of the defect candidate regions. This suppresses over-detection of defects arising from, for example, grime on the surface during external appearance inspection.