Efficiency of the Inertia Friction Welding Process and Its Dependence on Process Parameters

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2017-07, Vol.48 (7), p.3328-3342
• Main Authors: Senkov, O. N., Mahaffey, D. W., Tung, D. J., Zhang, W., Semiatin, S. L.
• Format: Article
• Language: English
• Subjects: Angular velocity; Bearings; Characterization and Evaluation of Materials; Chemistry and Materials Science; Efficiency; Energy conservation; Energy conversion efficiency; Flywheels; Friction stir welding; Friction welding; Kinetic energy; Materials Science; Metallic Materials; Metallurgy; Moments of inertia; Nanotechnology; Nickel base alloys; Process parameters; Structural Materials; Superalloys; Surfaces and Interfaces; Thin Films
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-017-4115-9

It has been widely assumed, but never proven, that the efficiency of the inertia friction welding (IFW) process is independent of process parameters and is relatively high, i.e ., ~70 to 95 pct. In the present work, the effect of IFW parameters on process efficiency was established. For this purpose, a series of IFW trials was conducted for the solid-state joining of two dissimilar nickel-base superalloys (LSHR and Mar-M247) using various combinations of initial kinetic energy ( i.e ., the total weld energy, E o ), initial flywheel angular velocity ( ω o ), flywheel moment of inertia ( I ), and axial compression force ( P ). The kinetics of the conversion of the welding energy to heating of the faying sample surfaces ( i.e ., the sample energy) vs parasitic losses to the welding machine itself were determined by measuring the friction torque on the sample surfaces ( M S ) and in the machine bearings ( M M ). It was found that the rotating parts of the welding machine can consume a significant fraction of the total energy. Specifically, the parasitic losses ranged from 28 to 80 pct of the total weld energy. The losses increased (and the corresponding IFW process efficiency decreased) as P increased (at constant I and E o ), I decreased (at constant P and E o ), and E o (or ω o ) increased (at constant P and I ). The results of this work thus provide guidelines for selecting process parameters which minimize energy losses and increase process efficiency during IFW.