Session: 03-08-01: Computational Modeling and Simulation for Advanced Manufacturing

Paper Number: 110852

110852 - Numerical Simulation of Rotary Friction Welding of a Titanium Alloy 

A two-dimensional model of continuous drive friction welding (CDFW) of Ti-6Al-4V tubes was developed using the ABAQUS modeling software. To avoid increasing the calculation cost, the heat transfer distance during the welding process is estimated, and the pipe length in the model is determined by the theory of heat transfer. The effect of interface temperature on frictional behavior was investigated during welding. The interface friction behavior changes with the increase of temperature during friction welding: The interface is mainly sliding friction behavior when the temperature is low; The interface friction behavior is mainly adhesive friction when the temperature is high (the friction pressure exceeds the yield strength of the material at this temperature). The yield strength of the material at high temperature is expressed by Arrhenius, and the constitutive equation has a good fitting effect on the high-temperature flow stress of the material. Using this constitutive equation, the calculation results are more accurate.  In addition, non-linear temperature-dependent material physical properties were considered. The thermal conductivity and specific heat capacity of Ti-6Al-4V increase with the increase of temperature. The effects of rotational speed, friction pressure and welding time on temperature field, stress-strain field, axial shortening and flash of the joint were studied. Results show that interface temperature rises rapidly early in the process, to reach a plateau later (over 1200 ℃); Take the process parameters of rotating speed 1500, axial pressure 55MPa, and welding time 2.6s as an example. 0~0.33s is the non-steady stage of the welding process. The welding temperature rises rapidly until 0.33s during this period, and the welding process begins to enter the steady-state stage. At this time, the welding interface flash also began to appear, and the weldment began to shorten. The flash is wrapped on the pipe wall and grows continuously as the welding progresses. The increase of weldment shortening increases almost linearly with the welding time caused by the welding entering the steady-state stage. The temperature of the welding interface tends to be stable so that the length of the weldment decreases with a constant shortening rate. The maximum plastic strain first appears near the interface flash, and then gradually extends to the interface center during the welding process. For constant welding time, temperature gradients and axial shortening increase with increasing rotating speed and friction pressure. In the unstable stage of the welding process, the higher the rotating speed, the greater the friction pressure, the earlier the appearance time of the welding interface flash, and the earlier the time of the weldment start to shorten. In the steady-state stage of the welding process, the higher the rotating speed, the greater the friction pressure, the higher the welding interface temperature, and the greater the final shortening of the weldment.; Following welding, the flash curls on the outer wall of the pipe, while the flash is symmetrical about the welding interface. Modeling results were validated with CDFW experiments.

Presenting Author: Achilles Vairis University of West Attica

Presenting Author Biography: Long research experience on friction welding processes with collaborations in China, the Russian Federation, South Korea, the UK, and Italy, which have produced joint publications on the subject. In addition, research work has focused on nano-materials, modeling of complex systems, and biomechanical systems, all of which have produced 91 journal papers, 67 conference papers, 1 book, 1 book chapter, and 4 patents. Publications have been cited over 2800 times with an impact of an h-index of 25 and an i-10 index of 56. Named in the top 2% of scientists worldwide as measured by the impact of their research publications, for 2020 and 2021 as well as for the whole career. Editor-in-Chief in the scientific journal Welding International published by Taylor & Francis.

Authors:

Wenxue Chen Northwestern Polytechnical University
Yaxin Xu Northwestern Polytechnical University
Achilles Vairis University of West Attica
Alexander Bikmeyev Northwestern Polytechnical University
Wenya Li Northwestern Polytechnical University