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Title: Improving Fatigue Performance of AHSS Welds

Reported herein is technical progress on a U.S. Department of Energy CRADA project with industry cost-share aimed at developing the technical basis and demonstrate the viability of innovative in-situ weld residual stresses mitigation technology that can substantially improve the weld fatigue performance and durability of auto-body structures. The developed technology would be costeffective and practical in high-volume vehicle production environment. Enhancing weld fatigue performance would address a critical technology gap that impedes the widespread use of advanced high-strength steels (AHSS) and other lightweight materials for auto body structure light-weighting. This means that the automotive industry can take full advantage of the AHSS in strength, durability and crashworthiness without the concern of the relatively weak weld fatigue performance. The project comprises both technological innovations in weld residual stress mitigation and due-diligence residual stress measurement and fatigue performance evaluation. Two approaches were investigated. The first one was the use of low temperature phase transformation (LTPT) weld filler wire, and the second focused on novel thermo-mechanical stress management technique. Both technical approaches have resulted in considerable improvement in fatigue lives of welded joints made of high-strength steels. Synchrotron diffraction measurement confirmed the reduction of high tensile weld residual stresses by the two weldmore » residual stress mitigation techniques.« less
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. ArcelorMittal USA, Harriman, TN (United States)
  3. Colorado School of Mines, Golden, CO (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
VT0505000; CEVT230
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor (HFIR)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States