A correction method for measuring residual stress of irregular cross-section weldments with the contour method

Zhe Cai, Jan Roman Hönnige, Matthew Roy

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Reliable evaluation of residual stress (RS) is essential in structural integrity assessment for critical
components such as welded joints. Being able to provide a 2D cross-sectional stress map over a cutting
plane, the contour method (CM) is often used for assessing butt-welds and other components with
rectangular cross-sections. For components such as T-sections, sacrificial material is often employed to
render a rectangular cutting path to prevent cutting artefacts. This is because artificial stresses can appear
in back-calculated results when there are sudden changes in cutting length during wire electro discharge
machining (WEDM). Sacrificial material can be used to compensate, but this may be impractical for
large or irregular components, where a perfect match between sacrificial material and the original
component cannot be easily achieved. We demonstrate a new technique for CM analysis employing a
stress-free sample, realised on welded Ti-6Al-4V T-sections to evaluate cutting artefacts (CAs) and the
proposed correction method. It will be shown that back calculated stress calculated based on stress-free
samples can be considered as artificial stresses introduced during WEDM process. A correction on a
conventional CM analysis has been achieved by subtracting these artificial stresses from original CM
results. The total artificial stress introduced by cutting a variable cross-section component will be
presented, along with a discussion on this effect on quantifying stresses at weld roots employing the CM.
It has been found that this technique is capable of mitigating cutting artefacts, especially when applied
to components with complicated profile where changes in cutting length exist.
Original languageEnglish
Title of host publication ICRS 11 - The 11th International Conference of Residual Stresses
Place of Publication Nancy,France
Publication statusPublished - 20 Feb 2023

Keywords

  • Contour Method
  • Residual Stress
  • Irregular components
  • WEDM
  • Cutting Artefacts

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