The　microstructure　and　mechanical　properties　of　steel　play　important　roles　in　its　wear　resistance.　In　this　study,　low　alloy　medium　carbon　steel　was　prepared　by　alternating　quenching　in　water　and　air　for　up　to　3　cycles,　followed　by　air　cooling　(AC)　to　room　temperature　(RQ),　to　obtain　different　microstructures.　The　mechanical　and　impact　abrasive　wear　properties　of　the　steel　were　tested　under　different　alternating　cycles,　and　the　influence　of　the　microstructure　on　the　wear　properties　and　mechanism　was　analyzed.　The　microstructure　of　the　steel　gradually　changed　from　pearlite　and　ferrite　to　fine　bainite,　martensite,　and　retained　austenite　during　the　quenching　process　with　an　increase　in　the　water-air　alternation　cycles.　Compared　with　no　alternation　quenching　cycle,　the　steel　after　alternating　3　cycles　had　the　best　combination　of　hardness,　toughness,　and　wear　resistance;　that　is,　the　hardness　and　impact　toughness　increased　from　245　to　464　HV,　and　28–50　J/cm2,　respectively,　and　the　impact　wear　resistance　increased　from　4.99　g-1　to　12.31　g-1.　This　was　mainly　owing　to　the　multiphase　microstructure,　such　as　bainite/martensite,　increasing　the　dislocation　density　of　the　sample　and　improving　the　mechanical　properties　of　the　steel,　and　the　work-hardening　of　the　retained　austenite　in　the　wear　surface　under　the　impact　deformation,　which　improved　the　wear　resistance　of　the　steel.　©　2022　Elsevier　B.V.