A.融化極氣體保護(hù)焊 B.鎢極氣體保護(hù)焊 C.以上都不對(duì)
A.弧長恢復(fù)時(shí)間越短越好 B.弧長恢復(fù)時(shí)間越長越好 C.與弧長恢復(fù)時(shí)間無關(guān)