SEDL / STP / STP1122-EB / STP24165S

Failure Modes in a Type 316 Stainless Steel under Biaxial Strain Cycling

Zamrik, SY
The Pennsylvania State University, University Park, PA

Davis, DC
The Pennsylvania State University, University Park, PA

Kulowitch, PJ
The Pennsylvania State University, University Park, PA

Pages: 20    Published: Jan 1992

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Abstract

Discussed are the failure modes observed in a Type 316 stainless steel under biaxial high temperature low cycle fatigue (HTLCF) and creep-fatigue strain cycling. All tests were carried out in air at 621°C (1150°F) using thin-walled tubular type specimens specially designed for axial, torsional, and combined axial-torsional (biaxial) cyclic loadings. Results from HTLCF and creep-fatigue tests at six different biaxiality ratios (λ = Δγ^xy/Δε^xx): 0.0, 1.0, 2.0, 2.5, 3.6, and ∞, are given. At these biaxiality ratios, crack initiation in HTLCF is a shear process and crack propagation occurs mainly in a normal mode. With the introduction of creep through a combined in-phase tensile-torsional hold-time imposed on the biaxial HTLCF cycle, the direction of the crack propagation was found to be dominated by the axial creep-fatigue component. These results are compared with some multiaxial fatigue strain-based failure criteria.