Experimental Investigations on Welding Stress Distribution in Thick Specimens After Postweld Heat Treatment and Ultrasonic Impact Treatment

2020 
This paper presents the welding residual stress distribution in thick specimens after postweld treatments (postweld heat treatment—PWHT, and ultrasonic impact treatment—UIT). Three specimens with a thickness of 40 mm were multipass butt-welded by the gas metal arc welding (GMAW). The surface stresses were evaluated by the hole-drilling (HD) and the x-ray diffraction (XRD) methods, while the internal stresses were determined by the contour method (CM). It is found that UIT has a local effect on the welding residual stress. It can convert the tensile welding stresses into compressive stresses and introduce about a 3-6 mm compressive stress layer at the treated surface with little effect on the stresses outside the treated region and the stress distribution in the interior weld zone. Additionally, UIT shows the same effect on the surface longitudinal and transverse stresses, which results in a similar distribution and magnitude of compressive longitudinal and transverse stresses on the treated regions. PWHT has a global stress release of the welding residual stress, resulting in almost uniform stress distribution in the specimen with the range from − 200 to 100 MPa. PWHT also causes the release of the compressive transverse stress in the interior.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    39
    References
    6
    Citations
    NaN
    KQI
    []