Device and method for co-axial and composite welding by adopting center negative pressure plasma arc and electron beam

The invention relates to a device and a method for co-axial and composite welding by adopting a center negative pressure plasma arc and an electron beam, and belongs to the technical field of welding equipment and method. Through an air extractor, a negative pressure state is formed in a hollow electrode placed in a plasma welding gun and the plasma arc central region below the hollow electrode; the electron beam generated by an electron beam welding gun co-axially penetrates through an inner cavity of the electrode and the central negative pressure region of the arc below the electrode through a negative pressure fixing chamber and the hollow electrode, and then the electron beam is focused on a welding workpiece; according to the electron beam and the peripheral coaxial plasma arc, the method for co-axial and composite welding by adopting the center negative pressure plasma arc and the electron beam is formed. According to the device and the method, a passage is provided for spreading the electron beam through the inner cavity of the hollow electrode and the negative pressure environment of the arc central region; the electron beam can be prevented from being crashed and impacted by atmosphere gas molecules; the energy density and energy conversion ratio of the electron beam are greatly improved; through compounding with the plasma arc, the shortcoming that the traditional electron beam welding has high requirements on processing and assembling welding joints is conquered, the welding gap adaptive capacity is improved.