Study Of Process And Characteristics For Underwater Consumable Electrode Arc Cutting

With the development of maritime strategy, building quantity of ships, coastal constructions, ocean platforms and submarine pipelines has increased greatly, which leads to an increase in the requirements of underwater cutting. There are many underwater cutting processes, which exits limitations. Because many equipments lost of high security and flexibility, as well as the high requirements and restrictive conditions of underwater equipment tooling and assembly under the depth of 60 meters. This paper introduces a new process of underwater consumable electrode arc cutting. It ignites the arc between the flux-cored wire and the test piece, uses arc heat to melt metal and blows away the melted metal simultaneously by the gas that flux core produced.This paper introduces the principle of underwater consumable electrode arc cutting process, designs the underwater cutting system, and then carries out underwater cutting experiments. The effect of underwater consumable electrode arc cutting process parameters on kerf shape was investigated, and the governing factors of underwater cutting arc stability was analyzed in this research. Furthermore, an alternating impulse signal was superimposed via coupling capacitor onto cutting arc by paralleling an ultrasonic frequency pulse generator with an ordinary cutting power supply, and an experimental system was constituted correspondingly. A number of cutting experiments were used to investigate the effect of the cutting process parameters (pulse current amplitude and pulse frequency) on kerf widths, bevel angle and straightness.Experimental results show that an integrated set of underwater consumable electrode arc cutting equipment which consists of high-power dc power supply, wire feeder, manipulating mechanism and water tank is stable. The cutting quality is decided by matching and optimizing among the three parameters of cutting current, arc voltage and cutting speed. In addition, the three parameters are closely related to cutting arc stability. The ultrasonic frequency pulse modulation strengthens the constricted degree and stiffness of the arc, and improves the kerf shape obviously.