Method for manufacturing reference piece for x-ray measurement of residual stress and reference piece for x-ray measurement of residual stress

Patent metadata

Field	Value
Publication number	US-12480894-B2
Application number	US-201917441049-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Mar 25, 2019
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

A metal material other than strain-free iron powder can be used as a reference piece for X-ray measurement of residual stress. The metal material is manufactured by nanocrystallizing at least a portion of a surface of a metal material, and then removing inherent strain by annealing the metal material, thereby eliminating stress.

First claim

The invention claimed is:

1 . A manufacturing method for a reference piece for X-ray measurement of residual stress, comprising, after at least a portion of a surface of SCM (steel chromium molybdenum steel materials), SUP (spring steel steel materials), SPCC (normal steel), SPHC (general hot rolled steel materials), or S 10 C (carbon steel for machine structures) has been nanocrystallized by shot peening, stress is reduced while maintaining a micro state of nanocrystallized crystal grains by annealing the same and an orientation of metal crystal planes facing in the same direction generated by the manufacturing method is scattered by recrystallizing/micronizing the same by shot peening,
wherein the residual stress in the reference piece for X-ray measurement of residual stress is −55 MPa or greater and 55 MPa or less, and wherein the shot peening is implemented with an air acceleration device with a projection air pressure in a range of 0.05-1.0 MPa.

2 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein a certain number of crystal grains for obtaining reliability in the X-ray measurement of residual stress are present within a range of the X-ray measurement of residual stress by shot peening.

3 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein nanocrystals are present on the metal material surface in a range of 0-50 μm.

4 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein the shot peening is implemented with a projected material having a Vickers hardness (JIS Z 2244) in a range of HV 1200-3000, and a grain size number (JIS R 6001) in a range of 20-220.

5 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein the shot peening is implemented with a projected material having a Vickers hardness (JIS Z 2244) in a range of HV 1700-3000, and a grain size number (JIS R 6001) in a range of 30-100.

6 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein the projection air pressure is in a range of 0.1-0.5 MPa.

7 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , a number of times annealing is performed is from 3 to 5.

8 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein annealing is performed by using a bright annealing furnace.

9 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein annealing is performed to heat to 180-500° C.

10 . The manufacturing method for a reference piece for X-ray measurement of residual stress according to claim 1 , wherein annealing is performed to heat to 180-300° C.

Assignees

• Sintokogio Ltd

Inventors

• Kobayashi Yuji
• Matsui Akinori
• Saito Yuta

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• C21D7/06

  by shot-peening or the like · CPC title

• C21D9/00

  Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor · CPC title

• C21D1/00

  General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering · CPC title

• C21D1/30

  Stress-relieving · CPC title