A series of reserved TIG welding experiments are carried out on a 3 mm thick 304 stainless steel plate. A clear image of the front fusion hole is captured by the CMOS vision detection system. By MATLAB image processing tool

the image processing algorithm in line with the characteristics of the fusion hole image is designed

the fusion hole-gap edge is gained

and the widths of the fusion hole and gap are calculated. The results show that the welding parameter window with stable fusion hole is relatively narrow

and the fusion hole can only maintain 4～5 s without adjustment in most cases. When the welding speed is constant

the welding current and the reserved gap are the important factors affecting the size of the fusion hole. Other parameters remain unchanged

the width of the fusion hole increases as the welding current increases;the width of the fusion hole also increases as the reserved gap increases

and shows a similar change rule.