In this paper, technology margin experiment of hollow cathode fusion are we
lding (FAW) and penetrating are welding (PAW) is presented in detail. The a
dvantages of PAW, compared with FAW, are better weld formation, narrower we
lds, as well as a larger welding technology margin. Technological experimen
t and hydraulic test for the Ti alloy pressure vessels with PAW are describ
ed. Also, the weld formation control on Ti alloys is preliminarily analyzed
. Finally, conclusions are addressed.