Radial distribution of variable polarity plasma arc pressure

Molten pool and weld formation of variable polarity plasma arc(VPPA) welding are influenced greatly by VPPA pressure.Therefore,researches on VPPA pressure are meaningful.Furthermore,discussions about radial distributions of VPPA pressure can actually guide mechanical analysis and numerical simulation of VPPA and its molten pool.In this paper,the distribution of VPPA pressure along the radial distance at different welding currents was measured and discussed by U-tube barometer.It was concluded that the radial distribution of VPPA pressure still belonged to Gaussian distribution rather than exponential distribution.Furthermore,the analyzed results show that the VPPA pressure increases with the increase of welding current,but its increasing rate tends to slow.