Nkk Corporation

Yuji Matoba

Toshio Koshihara

Koji Ishihara

Tsutomu Kawamura

Akira Kazama

Takahiko Oshige

Yuzo Sagawa

Kimio Takehara

Rokurou Misawa

Toru Hirashima

Shunichiro Ishida

Haruhito Okamoto

A method for detecting a surface flaw which includes the steps of (i) irradiating polarized light to a surface of a sample to be inspected and determining ellipso-parameters (.PSI., .DELTA.) of reflected light from the surface of the sample; (ii) irradiating light to a same position as irradiated by the polarized light and determining the intensity (I) of reflected light from the surface of the sample; and (iii) determining a type and grade of a flaw on the surface of the sample based on the ellipso-parameters (.PSI.,.DELTA.) and the reflected light intensity (I). A surface flaw detecting apparatus includes (i) a first measuring device for irradiating polarized light to a surface to be inspected and measuring ellipso-parameters (.PSI.,.DELTA.) of reflected light from the surface; (ii) a second measuring device for irradiating light to a same position as irradiated by the polarized light and measuring the intensity (I) of reflected light from that position; and (iii) an output device for outputting a three-dimensional coordinate position of .PSI., .DELTA., I representing the reflected light from the surface, while sorting the position into a preset zone.

Method and apparatus for detecting surface flaws

A method and apparatus for detecting a defective portion on the outer surface not exposed of a pipe, which comprises: heating or cooling a pipe, the outer surface of which is not exposed, from the side of the inner surface thereof so that a difference in temperature is produced between a portion of the inner surface of the pipe corresponding to an accumulation of foreign matters or a thinner portion as a defective portion on the outer surface not exposed of the pipe and a portion of the inner surface of the pipe corresponding to a normal portion of the outer surface of the pipe; then shooting the inner surface of the pipe by means of a thermal imaging system while the difference in temperature still remains on the inner surface of the pipe to obtain a thermal image of the difference in temperature; and detecting the accumulation of foreign matters or the thinner portion as the defective portion on the outer surface of the pipe by means of the thus obtained thermal image.

Method and apparatus for detecting defective portion on outer surface of

A method for detecting a thinned out portion on the inner surface or the outer surface of a pipe, comprising heating or cooling a pipe to be tested from the outer surface or the inner surface thereof so that a difference in temperature is produced between two portions of the outer surface or the inner surface of the pipe corresponding to a thinned out portion and a normal portion of the inner surface or the outer surface of the pipe; shooting the outer surface or the inner surface of the pipe by means of a thermal imaging system to obtain a thermal image of the difference in temperature; and then calculating a differential value of a temperature distribution of the thermal image of the difference in temperature on a line passing the highest temperature point or the lowest temperature point in the thermal image of the difference in temperature. Then, two points of inflection are determined on both sides of the highest temperature point or the lowest temperature point of the temperature distribution for the thinned out portion, on the basis of the differential value of the temperature distribution; and then an extent of the thinned out portion is detected on the basis of a distance between the two points of inflection of the temperature distribution.

Method for detecting thinned out portion on inner surface or outer

A method and an apparatus for detecting a defective portion on the inner surface of a pipe, the outer surface of which is exposed, includes: heating or cooling a pipe, the outer surface of which is exposed, from the side of the outer surface thereof so that a difference in temperature is produced between a portion of the outer surface of the pipe corresponding to an accumulation of foreign matters or a thinner portion as a defective portion on the inner surface thereof, and a portion of the outer surface of the pipe corresponding to a normal portion of the inner surface thereof; then shooting the outer surface of the pipe by means of a thermal imaging system while the above-mentioned difference in temperature still remains on the outer surface of the pipe to obtain a thermal image of the difference in temperature; and detecting the accumulation of foreign matters or the thinner portion as the defective portion of the inner surface of the pipe by means of the thus obtained thermal image.

Method and apparatus for detecting defective portion on inner surface of

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Tokyo, Japan

Yuji Matoba