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A Comprehensive Understanding of Machine and Material Behaviors during Inertia Friction Welding

Tung, Daniel Joseph
http://orcid.org/0000-0001-5995-558X
http://rave.ohiolink.edu/etdc/view?acc_num=osu14925491745339

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Welding Engineering.
Inertia Friction Welding (IFW), a critical process to many industries, currently relies on trial-and-error experimentation to optimize process parameters. Although this Edisonian approach is very effective, the high time and dollar costs incurred during process development are the driving force for better design approaches. Thermal-stress finite element modeling has been increasingly used to aid in process development in the literature; however, several fundamental questions on machine and material behaviors remain unanswered. The work presented here aims produce an analytical foundation to significantly reduce the costly physical experimentation currently required to design the inertia welding of production parts. Particularly, the work is centered around the following two major areas. First, machine behavior during IFW, which critically determines deformation and heating, had not been well understood to date. In order to properly characterize the IFW machine behavior, a novel method based on torque measurements was invented to measure machine efficiency, i.e. the ratio of the initial kinetic energy of the flywheel to that contributing to workpiece heating and deformation. The measured efficiency was validated by both simple energy balance calculations and more sophisticated finite element modeling. For the first time, the efficiency dependence on both process parameters (flywheel size, initial rotational velocity, axial load, and surface roughness) and materials (1018 steel, Low Solvus High Refractory LSHR and Waspaloy) was quantified using the torque based measurement method. The effect of process parameters on machine efficiency was analyzed to establish simple-to-use yet powerful equations for selection and optimization of IFW process parameters for making welds; however, design criteria such as geometry and material optimization were not addressed. Second, there had been a lack of understanding of the bond formation during IFW. In the present research, an interrupted welding study was developed utilizing purposefully-designed dissimilar metal couples to investigate bond formation for this specific material combination. The inertia welding process was interrupted at various times as the flywheel velocity decreased. The fraction of areas with intermixed metals was quantified to reveal the bond formation during IFW. The results revealed a relationship between the upset and the fraction of bonded material, which, interestingly, was found to be consistent to that established for roll bonding literature. The relationship is critical to studying the bonding mechanism and surface interactions during IFW. Moreover, it is essential to accurately interpret the modeling results to determine the extent of bonding using the computed strains near the workpiece interface. With this method developed, similar data can now be collected for additional similar and dissimilar material combinations. In summary, in the quest to develop, validate, and execute a modeling framework to study the inertia friction weldability of different alloy systems, particularly Fe- and Ni-base alloys, many new discoveries have been made to enhance the body of knowledge surrounding IFW. The data and trends discussed in this dissertation constitute a physics-based framework to understand the machine and material behaviors during IFW. Such a physics-based framework is essential to significantly reduce the costly trial-and-error experimentation currently required to successfully and consistently perform the inertia welding of production parts.
Wei Zhang (Advisor)
John Lippold (Committee Member)
David Phillips (Committee Member)
265 p.
Engineering; Materials Science
Inertia Friction Welding; Inertia Welding; Efficiency; Modeling; Bonding; Torque

Recommended Citations

Citations

  • Tung, D. J. (2017). A Comprehensive Understanding of Machine and Material Behaviors during Inertia Friction Welding [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu14925491745339

    APA Style (7th edition)

  • Tung, Daniel. A Comprehensive Understanding of Machine and Material Behaviors during Inertia Friction Welding. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu14925491745339.

    MLA Style (8th edition)

  • Tung, Daniel. "A Comprehensive Understanding of Machine and Material Behaviors during Inertia Friction Welding." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu14925491745339

    Chicago Manual of Style (17th edition)

osu14925491745339
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This open access ETD is published by The Ohio State University and OhioLINK.