Gas flow waveform modulation variable polarity plasma welding method

A gas flow waveform modulation variable polarity plasma welding method belongs to the technical field of welding methods. According to the invention, a regular plasma arch welding device is added with a gas flow waveform controller and a plasma gas control execution unit; the waveform output of the plasma gas flow can be realized during the welding process by controlling the plasma gas control execution unit; and the plasma gas flow is synchronously changed with the current during the welding process of the variable polarity plasma, so that the control of stability of the welding process and piercing can be realized. According to the invention, the stability of piercing and the welding process of the variable polarity plasma can be greatly improved and the stability is improved, so the quality of weld seam is conducive to be increased.