GB/T 26140-2023Non-destructive testing - Standard test method for determining residual stresses by neutron diffraction (English PDF)

1 Scope

This document specifies a method for measuring residual stress in polycrystalline materials by neutron diffraction: This document is applicable to homogeneous, heterogeneous and containing different crystal

Phase material sample testing:

This document briefly describes the principles of the neutron diffraction technique and provides the following recommendations:

---Appropriate diffraction crystal plane selection for measurements that should be carried out for different types of materials;

--- Selection of sample orientation in suitable measurements;

---The selection of the volume to be measured is related to the grain size and stress state of the material to be tested:

This document specifies the procedure for accurately locating and aligning the detection site within the neutron beam, and the procedure for accurately defining the sample volume of the material used for the measurement:

process:

This document specifies the precautions for calibrating neutron diffraction devices and specifies the technical method for obtaining stress-free reference values:

This document specifies various methods for performing neutron diffraction measurements, provides procedures for analyzing results and determining their statistical correlation, provides

Recommendations for the determination of reliable estimates of residual stress from strain measurement data and for the assessment of the uncertainty in the results:

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text: Among them, dated references

For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document:

EN 13925-3:2015 X-ray diffraction for non-destructive testing of polycrystalline and amorphous materials Part 3: Apparatus (Non- ments)

3 Terms and Definitions

The following terms and definitions apply to this document:

ISO and IEC maintain the following terminology databases for standardization work:

---ISO online browsing platform, the URL is https://www:iso:org/obp;

3:1 neutron absorption neutron absorption

The phenomenon of neutrons being captured by atomic nuclei:

Note: See reference [1] for the table of nuclear capture cross sections:

3:2 correction alignment

The adjustment made to the position and orientation of the sample and all components of the apparatus so that measurements can be made accurately at the expected sample location: