Characterization of residual stress as a function of friction stir welding parameters in oxide dispersion strengthened (ODS) steel MA956

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:647

Article

Brewer, L. N.¹  Bennett, M. S.¹  Baker, B. W.¹  Payzant, E. A.²  Sochalski-Kolbus, L. M.² 

[1] Naval Postgrad Sch, Monterey, CA 93943 USA

[2] Oak Ridge Natl Lab, Oak Ridge, TN USA

关键词: ODS steel;    Residual stress;    Friction stir welding;    X-ray diffraction;    Neutron diffraction;   

DOI  :  10.1016/j.msea.2015.09.020

来源: Elsevier

【 摘 要 】

Friction stir welding (FSW) can generate large residual stresses during solid state joining of oxide dispersion strengthened steels. In this work, a plate of MA956 steel was friction stir welded at three conditions: 500 rpm/25 mm per minute (mmpm), 400 rpm/50 mmpm and 400 rpm/100 mmpm. The residual stresses across these welds were measured using both x-ray and neutron diffraction techniques. The distribution and magnitude of the residual stresses agreed well between the two techniques. Longitudinal residual stresses up to eighty percent of the yield strength were observed for the 400 rpm/100 mmpm condition. The surface residual stresses were somewhat larger on the root side of the weld than on the crown side. Increases in the relative heat input during FSW decreased the measured residual stresses in the stir zone and the thermomechanically affected zone (TMAZ). Increasing the traverse rate while holding the rotational speed fixed increased the residual stress levels. The fatigue strength of the material is predicted to decrease by at least twenty percent with cracking most likely in the TMAZ. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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