ASTM E915-96(2002)

Standard Test Method for Verifying the Alignment of X-Ray Diffraction Instrumentation for Residual Stress Measurement

SIGNIFICANCE AND USE
This test method provides a means of verifying instrument alignment in order to quantify and minimize systematic experimental error in X-ray diffraction residual stress measurement. This method is suitable for application to conventional diffractometers or to X-ray diffraction instrumentation of either the diverging or parallel beam types.3 , 4  
Application of this test method requires the use of a flat specimen of stress-free material that produces diffraction in the angular region of the diffraction peak to be used for stress measurement. The specimen must be sufficiently fine-grained so that large numbers of individual crystals contribute to the diffraction peak produced. The crystals must provide intense diffraction at all angles of tilt, ψ, which will be employed (see Note 1).
Note 1—Complete freedom from preferred orientation in the stressfree specimen is, however, not critical in the application of the technique.
SCOPE
1.1 This test method covers the preparation and use of a flat stress-free test specimen for the purpose of checking the systematic error caused by instrument misalignment or sample positioning in X-ray diffraction residual stress measurement, or both.
1.2 This test method is applicable to apparatus intended for X-ray diffraction macroscopic residual stress measurement in polycrystalline samples employing measurement of a diffraction peak position in the high-back reflection region, and in which the , 2, and rotation axes can be made to coincide (see ).
1.3 This test method describes the use of iron powder which has been investigated in round-robin studies for the purpose of verifying the alignment of instrumentation intended for stress measurement in ferritic or martensitic steels. To verify instrument alignment prior to stress measurement in other alloys, base metal powder having the same crystal structure as the alloy should be prepared in similar fashion and used to check instrument alignment at the appropriate diffraction angle.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Apr-1996
• ICS: 19.100 - Non-destructive testing
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.13 - Residual Stress Measurement

Relations

• Replaces: ASTM E915-96 - Standard Test Method for Verifying the Alignment of X-Ray Diffraction Instrumentation for Residual Stress Measurement
• Effective Date: 10-Apr-1996
• Replaced By: ASTM E915-10 - Standard Test Method for Verifying the Alignment of X-Ray Diffraction Instrumentation for Residual Stress Measurement
• Effective Date: 01-Jun-2010
• Referred By: ASTM E2860-20 - Standard Test Method for Residual Stress Measurement by X-Ray Diffraction for Bearing Steels
• Effective Date: 10-Apr-1996
• Referred By: ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
• Effective Date: 10-Apr-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E915 – 96 (Reapproved 2002)
Standard Test Method for
Verifying the Alignment of X-Ray Diffraction Instrumentation
for Residual Stress Measurement
This standard is issued under the fixed designation E915; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope experimentalerrorinX-raydiffractionresidualstressmeasure-
ment. This method is suitable for application to conventional
1.1 This test method covers the preparation and use of a flat
diffractometersortoX-raydiffractioninstrumentationofeither
stress-free test specimen for the purpose of checking the
,
3 4
the diverging or parallel beam types.
systematic error caused by instrument misalignment or sample
3.2 Application of this test method requires the use of a flat
positioninginX-raydiffractionresidualstressmeasurement,or
specimenofstress-freematerialthatproducesdiffractioninthe
both.
angular region of the diffraction peak to be used for stress
1.2 This test method is applicable to apparatus intended for
measurement. The specimen must be sufficiently fine-grained
X-ray diffraction macroscopic residual stress measurement in
so that large numbers of individual crystals contribute to the
polycrystalline samples employing measurement of a diffrac-
diffraction peak produced. The crystals must provide intense
tion peak position in the high-back reflection region, and in
diffraction at all angles of tilt, c, which will be employed (see
which the u,2u, and c rotation axes can be made to coincide
Note 1).
(see Fig. 1).
1.3 Thistestmethoddescribestheuseofironpowderwhich
NOTE 1—Completefreedomfrompreferredorientationinthestressfree
has been investigated in round-robin studies for the purpose of
specimen is, however, not critical in the application of the technique.
verifying the alignment of instrumentation intended for stress
4. Procedure
measurement in ferritic or martensitic steels. To verify instru-
4.1 Instrument Alignment:
ment alignment prior to stress measurement in other alloys,
base metal powder having the same crystal structure as the 4.1.1 Align the X-ray diffraction instrumentation to be used
forresidualstressmeasurementinaccordancewiththeinstruc-
alloy should be prepared in similar fashion and used to check
instrument alignment at the appropriate diffraction angle. tions supplied by the manufacturer. In general, this alignment
must achieve the following, whether the u,2u, and c axes are
1.4 This standard does not purport to address all of the
variable or fixed (see Fig. 1):
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.1.1.1 The u,2u, and c axes shall coincide.
4.1.1.2 The incident X-ray beam shall be centered on the c
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. and2uaxes,withinafocusingrange,whichwillconformtothe
desired error and precision tolerances (see sections 5 and 6).
2. Referenced Documents
4.1.1.3 TheX-raytubefocalspot,the cand2uaxes,andthe
2.1 ASTM Standards: receiving slit positioned at 2u equals zero degrees shall be on
E11 SpecificationforWovenWireTestSieveClothandTest a line in the plane of diffraction. Alternatively, for instrumen-
Sieves tationlimitedtothebackreflectionregion,thediffractionangle
2u shall be calibrated.
3. Significance and Use
4.1.1.4 The proper sample position shall be established,
3.1 This test method provides a means of verifying instru-
using whatever means are provided with the instrument, such
ment alignment in order to quantify and minimize systematic that the surface of the sample is positioned at the u and c axes
, within the focal distance range which will conform to the
desired error and precision tolerances (see sections 5 and 6).
This test method is under the jurisdiction of ASTM Committee E28 on
4.1.1.5 The angle c must be determined accurately.
Mechanical Testing and is the direct responsibility of Subcommittee E28.13 on
Residual Stress Measurement.
Current edition approved Apr. 10, 1996. Published June 1996. Originally
published as E915–83. Last previous edition E915–90. DOI: 10.1520/E0915-
96R02. Hilley, M. E., Larson, J. A., Jatczak, C. F., and Ricklefs, R. E., eds., Residual
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Stress Measurement by X-ray Diffraction, SAE J784a, Society of Automotive
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Engrs., Inc., Warrendale, PA (1971).
Standards volume information, refer to the standard’s Document Summary page on “Standard Method for X-Ray Stress Measurement,” Committee on Mechanical
the ASTM website. Behavior of Materials, The Society of Materials Science, Japan, (20 April 1973).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E915 – 96 (2002)
FIG. 1 X-Ray Diffraction Stress Measurement Geometry and Angles Defined
4.2 X-Ray Optics: 4.4 Stress-Free Specimen Preparation:
4.2.1 When the Ka characteristic radiation doublet is used
4.4.1 Apermanentstress-freespecimenmaybepreparedby
for stress measurement, it is desirable to select incident and
mounting the powder on the face of a microscope slide or in a
receiving X-ray beam optics that will produce maximum
shallow powder tray (of the type used for powder diffraction
separation of the Ka −Ka doublet. Perform stress measure-
work on a diffractometer) using a 10% solution of nitrocellu-
1 2
ments on the stress-free specimen employing the Ka diffrac-
lose cement diluted with acetone as a suitable amorphous
tionpeakatall canglesinvestigated.Becauseresolutionofthe
binder. Place several drops of the solution on a clean micro-
Ka doublet may vary with the angle c, and because some
scopeslideorinasampletray,andsprinklethepowderintothe
instrumentationmaybeincapable(duetofixedX-rayoptics)of
binder. The powder may be spread and leveled with a second
obtaining resolution of the doublet, care must be taken not to
microscope slide. When a uniform flat surface has been
resolve the doublet at some c angles while blending the
produced by alternately wetting with the binder solution and
doublet into a single peak at other c angles.
wiping with a second slide, set the specimen aside and allow it
4.3 Selection of Powder for a Stress-Free Iron Specimen:
to dry for several hours. Excess amounts of the binder may
4.3.1 Useironpowderwithaparticlesizegreaterthan1µm
cause it to peel away from the surface of the microscope slide.
−5
(4 310 in.) (See Note 2.) Rewetting of the surface with acetone and redrying may
eliminate this difficulty. Make the surface of the specimen as
NOTE 2—Annealedarmcoironpowderof<45µm(3
...