| During high-speed Gas Metal Arc Welding (GMAW), the backward flowing molten jet with high momentum in weld pool is considered to be responsible for the formation of humping bead. Therefore, any techniques which can slow down the backwards flowing molten jet is thought to be beneficial to suppress humping bead. Thus, it is of great significance to take low-cost and flexible techniques to manipulate the backward flowing molten jet. This means not only suppressing humping bead and achieving high speed welding, but also a much higher welding efficiency and stronger competitiveness.In this study, external magnetic field is applied to the weld pool. Taking advantage of the electromagnetic forces generated by the intersection of welding current and magnetic flux density, the flowing velocity, momentum and distribution of the backward molten jet will be adjusted and humping bead can be suppressed, leading to a high-speed GMAW process.Six magnetic field generators are developed and the measuring method of the magnetic flux density along the welding center line is determined. The influence of the material of workbench, air gap, shape of magnet core, excitation current and excitation methods on the distribution of magnetic flux density is analyzed.A high-speed GMAW experimental system is constructed, and the magnetic field generator is successfully coupled with the system.High-speed GMAW experiment has been conducted and the effect of magnetic field on bead shape, arc and weld pool behavior is analyzed. The mechanism of high-speed GMAW with magnetic field was preliminarily analyzed. Butt joint experiment was conducted, and the potential of magnetic-controlled high-speed GMAW process applying in industry is confirmed. |
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