STP1175: Technique to Eliminate Helium Induced Weld Cracking in Stainless Steels

    Wang, C-A
    Research Assistant, Materials Engineering, Auburn University, AL

    Grossbeck, ML
    Research Staff Member, Oak Ridge National Laboratory, TN

    Chin, BA
    Professor, Materials Engineering, Auburn University, AL

    Pages: 10    Published: Jan 1994


    Abstract

    Experiments have shown that Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 MPa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. The results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

    Keywords:

    Austenitic stainless steel, tritium doping and decay, GTA welding, HAZ cracking, helium bubble growth


    Paper ID: STP23970S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP23970S


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