US 11,913,895 B2
Method for detecting occurrence of cracks and the like, device for detecting occurrence of cracks and the like, and program for detecting occurrence of cracks and the like
Yosuke Takeuchi, Musashino (JP); Takuya Kamisho, Musashino (JP); and Masamitsu Watanabe, Musashino (JP)
Assigned to NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Appl. No. 15/734,654
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed May 28, 2019, PCT No. PCT/JP2019/021116
§ 371(c)(1), (2) Date Dec. 3, 2020,
PCT Pub. No. WO2019/235303, PCT Pub. Date Dec. 12, 2019.
Claims priority of application No. 2018-107429 (JP), filed on Jun. 5, 2018.
Prior Publication US 2021/0231596 A1, Jul. 29, 2021
Int. Cl. G01N 27/20 (2006.01); G01N 3/08 (2006.01)
CPC G01N 27/20 (2013.01) [G01N 3/08 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A method for detecting occurrence of a crack or the like, comprising:
a measurement step of, by a current measurement device, measuring a value of a current flowing through a steel material that is applied with tensile stress, the current generated by the steel material being subjected to a hydrogen charging process of immersing the steel material in an aqueous solution and applying a negative potential to the steel material; and
a determination step of, by a device for detecting occurrence of a crack or the like, using the measured current value to determine occurrence of a crack in the steel material when an amount of change in the current flowing through the steel material, a change rate of the amount of change in the current, or a change rate of the change rate of the amount of change in the current exceeds a threshold value,
wherein in the determination step, occurrence of a crack in the steel material is determined when the change rate of the amount of change in the current is less than a negative value of an absolute value of the threshold value, and occurrence of fracture in the steel material is determined when the change rate exceeds the absolute value of the threshold value.