STP648: Effect of Residual Stress from Welding on the Fatigue Strength of Notched 347 Austenitic Stainless Steel

    Albertin, L
    Senior engineer, Westinghouse Research and Development Center, and fellow engineer, Electro-Mechanical Division, Westinghouse Electric Corporation, Pittsburgh, Pa

    Eiffler, EE
    Senior engineer, Westinghouse Research and Development Center, and fellow engineer, Electro-Mechanical Division, Westinghouse Electric Corporation, Pittsburgh, Pa

    Pages: 9    Published: Jan 1978


    Abstract

    The fatigue strength of Type 347 stainless steel forging prepared according to ASTM Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service (A 182) was investigated in the notch-free and notched condition including a residual stress from an arc strike simulating a local weld. The notched specimens were 22.2 and 50.8 mm (0.875 and 2 in.) in diameter with a stress concentration factor, Kt, of 5.3. The notch-free specimens were standard R. R. Moore types. In the notch-free condition, the fatigue strength at 106 cycles was found to be 234.4 MPa (34 ksi). For the 22.2 and 50.8-mm (0.875 and 2-in.) diameter notched specimens, the fatigue strength was 124 MPa (18 ksi). In the case of 50.8-mm (2-in.) diameter notch specimens subjected to the heat of an arc strike, the endurance strength was 83 MPa (12 ksi). Thus, the endurance strength of heated specimens was reduced to two thirds that of unheated notched specimens. While the notch sensitivity index was 0.20 for the unheated specimens, it was 0.43 for the notched specimens containing a residual stress from the heat of an arc strike.

    Keywords:

    fatigue strength at ∼ cycles, austenitic stainless steels, welding, residual stress, notch sensitivity, fatigue tests, weldments.


    Paper ID: STP33398S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP33398S


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