Method for measuring residual stress

Patent metadata

Field	Value
Publication number	US-2020340933-A1
Application number	US-201816961090-A
Country	US
Kind code	A1
Filing date	Dec 21, 2018
Priority date	Jan 29, 2018
Publication date	Oct 29, 2020
Grant date	—

Abstract

The present invention is a method for measuring a residual stress in a cast and forged steel product, the method using X-rays, 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 detected in the detecting, wherein, when the residual stress is measured for each of a plurality of measurement positions of the cast and forged steel product, the residual stress for each of the measurement positions is calculated in the calculating based on the diffraction ring for each of the measurement positions and an X-ray elastic constant which varies for each of the measurement positions.

First claim

1 . A method for measuring a residual stress in a cast and forged steel product, the method using X-rays, comprising:
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 detected in the detecting, wherein when the residual stress is measured for each of a plurality of measurement positions of the cast and forged steel product, the residual stress at each of the measurement positions is calculated in the calculating based on the diffraction ring at each of the measurement positions and an X-ray elastic constant which varies for each of the measurement positions.

2 . The method for measuring a residual stress according to claim 1 , wherein the X-ray elastic constant which varies for each of the measurement positions is determined based on at least one of: a half width of the diffracted X-rays originating from the X-rays, a chemical component of the cast and forged steel product, or a hardness of the cast and forged steel product.

3 . The method for measuring a residual stress according to claim 1 , wherein the measurement positions are arranged at intervals that fall within five times an irradiation diameter of the X-rays.

Assignees

• Kobe Steel Ltd

Inventors

• Matsuda Mariko
• Kabutomori Tatsuhiko
• Takamatsu Hiroyuki

Classifications

• G01L1/25 Primary

  using wave or particle radiation, e.g. X-rays {, microwaves}, neutrons (G01L1/24 takes precedence) · CPC title

• G01N2223/1016

  X-ray · CPC title

• G01N23/2055 Primary

  Analysing diffraction patterns · CPC title

• G01N23/205 Primary

  using diffraction cameras · CPC title

• G01N2223/624

  steel, castings · CPC title