In　this　study　the　fume　formation　rate　(　FFR)　of　the　flux　cored　wire　for　mild　steel　produced　by　three　different　plants　was　investigated.　The　fume　chemical　composition　analysis　was　obtained　by　inductively　coupled　mass　spectroscopy　(　ICP)　and　X-ray　diffraction　(　XRD).　The　morphology　and　granularity　of　ferrite　powder　produced　by　different　production　processes　were　obtained　by　scanning　electron　microscope　(　SEM)　analysis,　and　their　effects　on　the　FFR　of　the　wire　and　explanation　are　also　included.　In　the　present　paper,　results　demonstrate　that　the　welding　fume　contains　mainly　the　oxides　of　ferrite　and　manganese　(　similar　to　50%)　with　remained　evaporations　of　slag.　The　ferrite　powders　produced　by　different　production　processes　have　different　morphologies.　The　morphology　of　ferrite　powders　has　limited　effect　on　the　FFR　which　fluctuates　orderly　on　a　small　scale　with　various　granularity　distributions　of　ferrite　powders.　The　FFR　is　lowered　when　the　granularity　of　ferrite　powders　retains　between　80　and　120　meshes　(　-210　+　130　mu　m).