PWHT (post weld heat treatment) is widely used to eliminate welding residual stress, but how to evaluate the effectiveness? what are the commonly used methods to measure welding residual stress in a component in or to be in service? Any standards?
Sin2(ψ)-2θ method was used to analyze the residual stress
https://www.sciencedirect.com/science/article/pii/S0921509322000016?dgcid=raven_sd_aip_email here you have a paper where they used it
https://link.springer.com/article/10.1007%2FBF03321387
https://af.booksc.eu/book/22095679/872bc6
Hi dear, for small samples, it is possible to use XRD as effective method to determine for calculating residual stress,however by measuring angular distortion, you can fell how much residual stress decrease or increase.then XRD method provide an quantity value of residual stresses while angular distortion just give a qualify value for comparing.
As already written above and suggested in the papers posted the most common technique is XRD analysis (X Ray Diffraction). Another powerful method is the Neutron diffraction having the disadvantage of being more expensive (you need a neutron stream) and it will activate your material.
Hi Wei,
There is some guidance on the level of reduction of residual stresses following PWHT in the British Standard BS 7910 (see https://shop.bsigroup.com/products/guide-to-methods-for-assessing-the-acceptability-of-flaws-in-metallic-structures/standard).
The following articles discuss the methods for dealing with residual stresses that a written into BS 7910.
https://www.twi-global.com/technical-knowledge/published-papers/effects-of-mechanical-loading-on-residual-stress-and-fracture-part-ii-validation-of-the-bs-79102013-rules
https://www.twi-global.com/technical-knowledge/published-papers/effects-of-mechanical-loading-on-residual-stress-and-fracture-part-i-background-to-the-bs-79102013-rules
https://www.twi-global.com/technical-knowledge/published-papers/finite-element-residual-stress-prediction-after-pwht-of-branch-pipe-connection
https://www.twi-global.com/technical-knowledge/published-papers/measurement-and-modelling-of-residual-stresses-in-offshore-circumferential-welds
https://www.hse.gov.uk/research/rrhtm/rr938.htm
Article Residual Stress Measurements in Offshore Wind Monopile Weldm...
https://bura.brunel.ac.uk/bitstream/2438/19658/1/FullText.pdf
Regards,
Simon
First of all, to evaluate the residual welding stress, you have to measure it by three different distraction techniques, distraction and distraction, now common X-ray diffraction, I recommend you to read this article
First of all, to evaluate the residual welding stress, you have to measure it by three different distraction techniques, distraction and distraction, now common X-ray diffraction, I recommend you to read this article
https://www.researchgate.net/publication/350413478_Prediction_and_numerical_simulation_of_residual_stress_in_multi-pass_pipe_welds
https://www.researchgate.net/publication/350413478_Prediction_and_numerical_simulation_of_residual_stress_in_multi-pass_pipe_welds
https://www.researchgate.net/publication/357861670_The_Effect_of_Heat_Input_Parameters_on_Residual_Stress_Distribution_by_Numerical_Simulation_You_may_also_like_Experimental_study_on_the_evolution_law_of_residual_stress_in_the_fatigue_process_of_induc
Dear Wei Peng,
From my knowledge, XDR is a good and effective method to measure residual stress.
All the best.
IDIR
You could also check the Blind Hole Drilling technique for components in service. The technique is a bit old-fashioned maybe and less accurate than XRD but the equipment can easily be carried on site. Also, take in mind that it is semi-destructive cause you drill a small hole on the sample. Maybe in some cases can be repaired with cladding or even not depending on the application. Good luck!
As the experts have already appointed, non-destructive techniques such as XRD, Magnetic Method and Ultrasonic Examination can be used. But it is recommended to do this tests in absense of other working and service stresses, in order to avoid interference with actual test results for residual stress in welded joints.
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