Abstract
Results of uniaxial tensile, creep and high temperature (620°C) fatigue tests are presented for both tungsten inert gas (TIG) butt-welded, and non-welded, thin-section specimens of the nickel-base superalloy INCONEL 718 (IN718).
An efficient, distortion-mitigating welding procedure has been devised using ABAQUS finite element (FE) simulations of the arc welding process, and subsequently implemented to manufacture TIG butt-welded specimens. By avoiding out-of-plane distortions that previously hampered uniaxial testing, better test data has been obtained, leading to more reliable material data for IN718 welds, which can be used for more accurate life assessments for shell structures and components.
It has been confirmed that IN718 welds are significantly less ductile than the parent material, and although welded IN718 exhibits comparatively little loss of tensile strength, its creep and high temperature fatigue properties are severely compromised. The lower performance of the welded specimens is attributed to the microstructural differences when compared with the non-welded material.
Life predictions from a case study of a welded feature in an IN718 generic spoke structure, determined using three-dimensional quasi-static elastic-plastic and creep FE analyses, are demonstrated. Since the welds have been found to exhibit noticeably depleted mechanical properties, a multi-material analysis is necessary for accurate predictions. The effect of including a weld in a critical region is investigated for both constant (creep) and cyclic loading conditions at 620°C. Creep damage and Smith, Watson and Topper (SWT) strain parameter lifing methods are used, based upon material properties determined using the test specimen data.
An efficient, distortion-mitigating welding procedure has been devised using ABAQUS finite element (FE) simulations of the arc welding process, and subsequently implemented to manufacture TIG butt-welded specimens. By avoiding out-of-plane distortions that previously hampered uniaxial testing, better test data has been obtained, leading to more reliable material data for IN718 welds, which can be used for more accurate life assessments for shell structures and components.
It has been confirmed that IN718 welds are significantly less ductile than the parent material, and although welded IN718 exhibits comparatively little loss of tensile strength, its creep and high temperature fatigue properties are severely compromised. The lower performance of the welded specimens is attributed to the microstructural differences when compared with the non-welded material.
Life predictions from a case study of a welded feature in an IN718 generic spoke structure, determined using three-dimensional quasi-static elastic-plastic and creep FE analyses, are demonstrated. Since the welds have been found to exhibit noticeably depleted mechanical properties, a multi-material analysis is necessary for accurate predictions. The effect of including a weld in a critical region is investigated for both constant (creep) and cyclic loading conditions at 620°C. Creep damage and Smith, Watson and Topper (SWT) strain parameter lifing methods are used, based upon material properties determined using the test specimen data.
| Original language | English |
|---|---|
| Publication status | Published - 2009 |
| Event | Environmentally Friendly Aeroengine (VITAL) - Budapest, Hungary Duration: 9 Mar 2009 → 10 Mar 2009 |
Workshop
| Workshop | Environmentally Friendly Aeroengine (VITAL) |
|---|---|
| Country/Territory | Hungary |
| City | Budapest |
| Period | 9/03/09 → 10/03/09 |