Characteristic Study Of Electron Beam Welding With Filler Wire Based On Visual Sensor

In this paper, the influence of welding process parameters on welding process ofelectron beam welding with filler wire has been study firstly. Then, the meltingdynamics of filler wire and the effects of filler wire on the dynamic behavior of weldingpool and keyhole have been study with the aid of CCD visual sensing system on theself-built test platform.The results showed that front feeding is more stable than rear feeding during EBWwith filler wire. And the front feeding is more easily adapt to the fluctuation during thewelding process. With the increase of wire feeding angle, the blocking effects of wire onelectron beam is waning and the penetration during the welding process is increasing.Meanwhile, the directivity of the feeding wire is better which is more suitable forwelding. A best weld appearance can be obtained when wire beam position located inthe interval of [-0.7mm,0.9mm]. Linear energy locating in interval of [-0.7mm,0.9mm] is a necessary condition for good weld appearance. And only the energy per unitvolume wire reaches42.45ηW/mm3can obtain good weld appearance. Front feedingwith large feeding angle, under the condition of a wire feeding rate of187cm/min, awelding speed of200mm/min, and a welding current of25mA were desirable forachieving optimal weld appearance.A systematic study of the filler wire melting dynamics based on the optimal resultshowed that the filler wire’s melting and transition behaviors can be divided into fivecategories, named as "Direct Transition","Molten Metal Bridge Transition ","SmallDroplet","Big Droplet", and "Mixed Transition". The welding process can be carriedout with high stability and the Beam-Wire-Weld Pool Coupling Model couples best onlywhen the filler wire transits into the welding pool by molten metal bridge.At last, the dynamic behavior of weld pool and keyhole of ’’ Molten Metal BridgeTransition "was studied. The results showed that the weld pool area of EBW with fillerwire increased and the keyhole area decreased relative to EBW without filler wire. Withthe increase of the wire feed rate, the molten pool area increases, the area of the keyholeincreased firstly and then decreases. Meanwhile,the fluctuation margin of welding pooland keyhole increase and the vibration frequency decreases.