The applicability of a recently introduced method will be discussed for the determination and -software- correction of alignment errors in XRD residual stress methods. For residual stress measurements with the omega-offset method the equatorial beam misalignment and the specimen displacement are relevant and the axial beam misalignment can be ignored. With the psi-tilt method the axial beam misalignment and the specimen displacement are relevant and the equatorial beam misalignment can be ignored. The two relevant alignment errors can be determined independently even when both errors are present. The method allows a free choice for the material of the stress-free reference sample. Each alignment error is described with only one distance parameter independent from the diffraction angle investigated or tilt angle applied. Hence, the alignment errors can be determined at one diffraction angle and applied over the complete 2θ range and other tilt angles than used for the determination of the errors. This will be demonstrated with measurements in the psi-stress set-up. The analysis and software correction of alignment errors makes the result fully independent of the alignment condition of the instrument. It allows comparison of stress results obtained in different laboratories and it is therefore a valuable addition to the international normalization procedure for XRD residual stress measurements.
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