A.砂料包埋不當(dāng) B.焊煤質(zhì)量差 C.火焰掌握不好 D.焊料放得位置不準(zhǔn) E.焊媒攤放面太廣
A.10% B.20% C.25% D.30% E.45%
A.10% B.20% C.25% D.30% E.35%