Control of resistance heat and optimization of wire feeding parameters in laser hot wire welding

In laser hot wire welding process, it is necessary to choose wire feeding parameters to guarantee proper resistance heat for stable metal transfer and high-efficiency deposition. In this paper, the influence of resistance heat on wire transfer was observed by high speed imaging, and the wire temperature under the optimal resistance heat was measured by the infrared ratio temperature measure. The experimental results show that the position 30 mm away from the contact tube end could be used as characteristic point, whose temperature was measured as the criterion of the optimal resistance heat. A transient heat conduction model of the wire was established and the characteristic point temperatures under different feeding wire parameters were calculated by numerical simulation. The wire feeding parameters for the optimal resistance heat were predicted based on the simulated results. By comparing the optimal currents under different wire feeding rates, it was found that the ratio of the square of current and wire feeding rate kept constant, which was helpful to choose wire feeding parameters rapidly.