The　purpose　of　this　study　was　to　clarify　the　effect　of　boron　content　on　the　microstructure　evolution,　mechanical　properties,　and　three-body　abrasive　wear　property　of　as-cast　Fe-Si-Mn-Cr-B　alloys,　and　to　reveal　the　wear　mechanism　of　Fe-Si-Mn-Cr-B　alloys.　The　results　indicated　that　the　microstructure　of　the　Fe-Si-Mn-Cr-B　alloy　was　mainly　composed　of　bainite,　retained　austenite　(RA),　M3B2,　and　M2B　(M　stands　for　the　metal　atom,　in　this　case,　it　refers　to　Fe,　Cr,　and　Mn).　With　the　increase　of　boron　content,　the　volume　fraction　of　the　boride　phase　increased,　the　morphology　of　the　boride　phase　was　dominated　by　fishbone,　the　microhardness　of　the　boride　phase　and　the　macrohardness　of　the　alloy　increased,　and　the　wear　resistance　of　the　alloy　was　significantly　enhanced.　Compared　with　the　0.5　wt.%　B　alloy,　the　macrohardness　of　the　2.0　wt.%　B　alloy　was　increased　by　19.5%,　the　maximum　microhardness　of　the　boride　phase　reached　1440　FIV02,　the　Charpy　impact　toughness　was　reduced　by　45%,　and　the　wear　resistance　was　increased　by　268%.　The　morphology,　content　and　distribution　of　the　boride　phase　play　a　key　role　in　improving　the　hardness　and　wear　resistance　of　the　alloy.　The　synergy　between　the　high-hardness　boride　phase　and　the　softer　metal　matrix　phase,　which　was　composed　of　bainite　and　RA,　gave　the　alloy　excellent　wear　resistance.　The　main　wear　mechanisms　of　the　alloy　were　abrasive　wear　and　fretting　wear.　(C)　2020　The　Authors.　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://creativecommons.org/licenses/by-nc-nd/4.01).