Research on Metallurgical Structure and Hardness of LY12 Aluminum Alloy Weld Zone under TIG and A-TIG

摘要

This paper studied and framed TIG and A-TIG welding procedure of LY12 aluminum alloy and analyzed the metallurgical structure and hardness of weld zone of TIG and A-TIG under different welding current. The result showed the strengthening phase which separated out from the basal body of TIG weld zone was obviously fewer than A-TIG and the strengthening phase of TIG obviously decreased when welding current increased. Compared with TIG weld zone, surface activating flux changed the metallurgical structure of A-TIG weld zone and the strengthening phase of A-TIG weld zone was more than TIG. The strengthening phase of A-TIG weld zone did not obviously decreased when welding current increased that implied the strengthening phase of A-TIG did not obviously dissolve into the basal body as TIG and only coarsened with the increase of welding current. The hardness experiment of weld zone showed that the hardness of A-TIG weld zone was higher than TIG and the hardness of 60%NaF+40%SiO_2 activating flux of A-TIG weld zone was higher than 40%NaF+60%SiO_2 activating flux.