Improvement of Weld Quality in Electron Beam Welding by High-Voltage Power Supply Applications

Electron beam welding (EBW), as a high-energy-density welding technology, holds significant application value in aerospace and precision manufacturing. The performance of its core component—the high-voltage power supply—directly determines the stability and reliability of the electron beam, thereby influencing weld quality. This article explores how high-voltage power supplies, through precise control, optimize the weld formation process and reduce defects based on their technical characteristics.
The stability of the high-voltage power supply is fundamental to ensuring EBW quality. The accelerating voltage typically required for EBW ranges from 60 to 150 kV, with beam current stability better than 0.5% and a ripple coefficient less than 1%. Fluctuations in voltage or current can cause energy instability in the electron beam, leading to defects such as inconsistent penetration, porosity, and cracks. The adoption of high-frequency switching power supply technology based on inverters, combined with hybrid control strategies like PWM (Pulse Width Modulation) and PFM (Pulse Frequency Modulation), can effectively reduce switching losses and improve power supply response speed and stability, ensuring consistent energy transfer during electron beam workpiece bombardment.
Precise adjustment of high-voltage power supply parameters directly influences the optimization of the welding process. Research indicates that excessively high electron beam currents and welding speeds can cause rapid vaporization of aluminum alloys, forming pores and intermetallic compounds that reduce ductility. In contrast, using lower beam currents (e.g., 23–40 mA) and moderate welding speeds (e.g., 8 mm/s) stabilizes the weld pool formation and yields defect-free welds. Furthermore, techniques such as pulsed electron beam or variable-focus welding modes allow the power supply to output high peak power, increasing metal vapor reaction forces and enhancing keyhole effects, thereby improving penetration and weld uniformity.
Advancements in high-voltage power supply technology have also facilitated new processes such as active electron beam welding. By applying activators like SiO₂ and Cr₂O₃ on the welding surface, the flow characteristics of the molten pool can be altered, increasing penetration depth by more than twofold and improving weld formation. Additionally, the multifunctional integrated control of high-voltage power supports pre-welding treatments (e.g., defocused electron beam preheating and cleaning) and post-weld modification, further reducing tendencies for porosity and cracking.
In summary, performance enhancement and precise control of high-voltage power supplies are key to optimizing electron beam weld quality. With further integration of high-frequency inverter technology, intelligent control strategies, and new processes, high-voltage power supplies will continue to advance electron beam welding toward higher efficiency and reliability.