US 12,241,803 B2
Method for measuring residual stress
Mariko Matsuda, Takasago (JP); Tatsuhiko Kabutomori, Takasago (JP); and Hiroyuki Takamatsu, Kobe (JP)
Assigned to Kobe Steel, Ltd., Kobe (JP)
Appl. No. 18/000,464
Filed by Kobe Steel, Ltd., Kobe (JP)
PCT Filed Apr. 22, 2021, PCT No. PCT/JP2021/016328
§ 371(c)(1), (2) Date Dec. 1, 2022,
PCT Pub. No. WO2021/246080, PCT Pub. Date Dec. 9, 2021.
Claims priority of application No. 2020-096360 (JP), filed on Jun. 2, 2020.
Prior Publication US 2023/0304876 A1, Sep. 28, 2023
Int. Cl. G01L 5/00 (2006.01); G01L 1/25 (2006.01); G01N 23/2055 (2018.01); G01N 23/205 (2018.01)
CPC G01L 5/0047 (2013.01) [G01L 1/25 (2013.01); G01N 23/2055 (2013.01); G01N 23/205 (2013.01); G01N 2223/3303 (2013.01); G01N 2223/607 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for measuring a residual stress of a fillet portion of a metallic structure, the metallic structure comprising:
an axis portion; and
a flange portion protruding radially from the axis portion,
wherein the metallic structure comprises the fillet portion in a connection portion between the axis portion and the flange portion,
the method comprising:
calculating the residual stress by a cos α method, by using an X-ray stress measuring apparatus comprising:
an irradiation portion which delivers X-rays;
a two-dimensional detector which detects a diffraction ring generated by Bragg diffraction of the X-rays delivered from the irradiation portion to the fillet portion; and
a housing in which the irradiation portion and the two-dimensional detector are mounted,
wherein
in a case in which an angle of incidence of the X-rays is denoted by Ψ [°], a fillet radius of the fillet portion is denoted by R [mm], a fillet angle of the fillet portion is denoted by θ [°], a vertical width of the housing is denoted by W [mm], a width of a detection region of the two-dimensional detector is denoted by D [mm], a complementary angle of a Bragg angle is denoted by η [°], and an interval between the flange portion and an imaginary straight line which passes through a fillet center and is parallel to the flange portion is denoted by a [mm], formula 1 is satisfied:
D≤W  1
in a case in which Ψ≥0, an irradiation distance L [mm] of the X-rays, the irradiation distance L being based on the two-dimensional detector in the calculating, satisfies formula 2, and
in a case in which Ψ<0, the irradiation distance L in the calculating satisfies formula 3,

OG Complex Work Unit Math
wherein with respect to an imaginary straight line which passes through a measurement site and the fillet center, the angle of incidence Ψ is positive in a case of tilting toward the axis portion, and is negative in a case of tilting toward the flange portion.