Shape prediction of a hot formed component in nickel-base superalloys

Document identifier: oai:DiVA.org:ltu-76239
Keyword: Engineering and Technology, Materials Engineering, Metallurgy and Metallic Materials, Teknik och teknologier, Materialteknik, Metallurgi och metalliska material, Manufacturing, Surface and Joining Technology, Bearbetnings-, yt- och fogningsteknik, Anisotropy, Hot forming, Alloy 718, Haynes 282, Stress relaxation, Superalloy, Hållfasthetslära, Solid Mechanics
Relevant Sustainable Development Goals (SDGs):
SDG 9 Industry, innovation and infrastructureSDG 11 Sustainable cities and communities
The SDG label(s) above have been assigned by OSDG.ai

Abstract:

Current manufacturing processes of advanced aero engine components in nickel-base superalloys are performed at approximately 950 °C, with varying holding times, to reduce the amount of residual stresses, and thereby shape deviations, over the part. The aim of such procedures is to obtain the final geometry of the component within tolerance and avoid costly tryouts, which can be unfavorable to the competitiveness of the aerospace industry. In addition, a reduction in the forming temperature or holding time may significantly reduce the energy consumption and carbon dioxide (CO2) emissions while increasing the ecological sustainability of the process. In this work, the numerical study of a hot forming procedure of a double-curved component in Haynes® 282® is presented. The influence of the forming temperature and holding time on the predicted amount of springback at different stages of the hot forming procedure is assessed. The resulting shape distortions are compared with identical FE analyses in alloy 718 at 870 °C available in literature. The anisotropic properties of the material are determined at temperatures ranging from 20 to 1000 °C. A qualitative analysis of the different types of serrations present in the hardening curves between 300 and 900 °C is included in the study. Microstructural observations of selected specimens are correlated to the material-characterization tests. The thermo-mechanical data is used as input to the novel version of the Barlat Yld2000-2D material model in LS-DYNA. The results show that forming of Haynes® 282® at 870 °C produces high shape distortions over the part with values beyond the sheet thickness, in contrast to the response of alloy 718. A comparison of the stress-relaxation rate with available data in literature for alloy 718 at 870 °C reveals that Haynes® 282® relaxes about 50% slower than alloy 718, whereas reasonably analogous at 950 °C. An increase in the forming temperature to 950 °C significantly reduces the amount of springback. Therefore, it can be concluded that forming of Haynes® 282® requires a higher temperature than reported for alloy 718 to reach similar amount of springback. The presented studies indicate that the use of advanced anisotropic models together with the thermo-mechanical properties and stress-relaxation behavior of the material is of utmost importance to accurately predict the final geometry of lightweight components of interest to the aerospace industry.

Authors

Lluís Pérez Caro

Luleå tekniska universitet; Material- och solidmekanik; RISE IVF AB; Solid Mechanics
Other publications >>

Eva-Lis Odenberger

Luleå tekniska universitet; Material- och solidmekanik; RISE IVF AB; Solid Mechanics
Other publications >>

Fredrik Niklasson

GKN Aerospace Sweden AB
Other publications >>

Mats Oldenburg

Luleå tekniska universitet; Material- och solidmekanik; Solid Mechanics
Other publications >>

Record metadata

Click to view metadata