US 11,898,995 B2
Method for evaluating crack in metal member and method for evaluating fatigue damage in metal member
Hiroaki Fukushima, Tokyo (JP); Yuichi Hirakawa, Tokyo (JP); Hiroaki Yoshida, Yokohama (JP); Masahiko Yamashita, Yokohama (JP); and Takeo Tokumoto, Yokohama (JP)
Assigned to MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP)
Appl. No. 17/612,070
Filed by Mitsubishi Power, Ltd., Kanagawa (JP)
PCT Filed Jul. 2, 2020, PCT No. PCT/JP2020/025995
§ 371(c)(1), (2) Date Nov. 17, 2021,
PCT Pub. No. WO2021/002424, PCT Pub. Date Jan. 7, 2021.
Claims priority of application No. 2019-125456 (JP), filed on Jul. 4, 2019.
Prior Publication US 2022/0349790 A1, Nov. 3, 2022
Int. Cl. G01N 3/06 (2006.01); G01N 33/2045 (2019.01); G01N 3/34 (2006.01)
CPC G01N 3/068 (2013.01) [G01N 3/34 (2013.01); G01N 33/2045 (2019.01)] 9 Claims
OG exemplary drawing
 
1. A method for evaluating a crack in a metal, the method comprising:
a first removal step of performing electrolytic treatment on a metal having an oxide scale layer formed on a surface thereof until a scale crack is generated in the oxide scale layer;
a second removal step of removing the oxide scale layer by performing the electrolytic treatment until the scale crack generated in the first removal step disappears; and
an evaluation step of measuring and evaluating a crack formed on a surface of a base material of the metal in which the scale crack has disappeared in the second removal step,
wherein the first removal step includes:
a step of performing the electrolytic treatment on the metal having oxide scale generated on the surface thereof;
a step of acquiring a first image by imaging the oxide scale; and
a step of determining whether or not the scale crack has been generated in the oxide scale on the basis of the first image by comparison of images, and
the second removal step includes:
a step of performing the electrolytic treatment on the metal in which the scale crack is generated;
a step of acquiring a second image by imaging the oxide scale; and
a step of determining whether or not the scale crack has disappeared on the basis of the second image by comparison of images.