In　this　work,　the　effects　of　oxygen　content　and　inclusions　on　the　microstructure　and　impact　toughness　of　the　metal-cored　wire　E120C-K4　deposited　metal　were　studied　by　changing　the　shielding　gas　ratio　and　Zr-Ti,　Ti-B　microalloying.　The　results　showed　that:　with　the　increase　of　oxygen　content　in　deposited　metal　of　metal　cored　wire　E120C-K4,　grain　size　of　microstructure　of　deposited　metal　increased,　which　is　similar　incontent　of　granular　bainite　as　well　as　the　size　and　content　of　inclusions,　impact　toughness　drastically　deteriorated.　Under　the　combined　effect　of　Zr　and　Ti,　the　proportion　of　inclusions　per　unit　area　in　the　deposited　metal　decreased,　the　average　particle　size　of　inclusions　fell　into　0.4-0.7　μm　range,　providing　a　large　number　of　potential　nucleation　spot　for　acicular　ferrite(AF),　so　improving　the　impact　absorbing　energy　of　deposited　metal.　©　2020,　Materials　Review　Magazine.　All　right　reserved.